Wyo. Code R. 020-0011-11
Chapter 11: Design and Construction Standards for Sewerage Systems, treatment works, disposal systems or other facilities capable of causing or contributing to pollution and mobile home park and campground sewerage and public water supply distribution systems
Effective Date: 03/23/2015 to 06/29/2018
Rule Type: Superceded Rules & Regulations
Reference Number: 020.0011.11.03232015
SEWERAGE SYSTEMS, TREATMENT WORKS, DISPOSAL SYSTEMS OR OTHER FACILITIES CAPABLE OF CAUSING OR CONTRIBUTING TO POLLUTION AND MOBILE HOME PARK AND CAMPGROUND SEWERAGE AND PUBLIC WATER SUPPLY DISTRIBUTION SYSTEMS
Section 1. Authority. ... 1 Section 2. Purpose. ... 1 Section 3. Intent. ... 1 Section 4. Definitions. ... 1 Section 5. Facilities and Systems Not Specifically Covered by These Standards. ... 4 Section 6. Engineering Design Report. ... 4 Section 7. Plans and Specifications Content. ... 6
WORKS, AND DISPOSAL SYSTEMS
Section 8. General. ... 9 Section 9. Design of Sewers. ... 9 Section 10. Pumping stations. ... 14 Section 11. General Treatment Plant Considerations. ... 19 Section 12. Pretreatment. ... 22 Section 13. Primary Treatment. ... 26 Section 14. Activated Sludge. ... 28 Section 15. Attached Growth Systems. ... 33
Section 16. Combination systems. ... 35 Section 17. Secondary settling. ... 35 Section 18. Lagoons. ... 38 Section 19. Tertiary treatment systems. ... 41 Section 20. Sludge Handling, Treatment and Disposal. ... 45 Section 21. Disinfection. ... 51 Section 22. Effluent Structures. ... 54 Section 23. Laboratory requirements. ... 54 Section 24. Operation and Maintenance Manuals. ... 56
Section 25. General. ... 59 Section 26. Discharge to Public Sewerage System. ... 59 Section 27. Domestic Wastes from Commercial/Industrial Facilities. ... 59 Section 28. Biological Treatment Ponds. ... 59 Section 29. Feedlots. ... 63 Section 30. Non-biological Treatment Ponds. ... 66 Section 31. Sedimentation Control Facilities. ... 70
SMALL WASTEWATER SYSTEMS
Section 32. Reserved. ... 72 Section 33. Reserved. ... 72 Section 34. Reserved. ... 72
Section 35. Reserved. ... 72 Section 36. Reserved. ... 72 Section 37. Reserved. ... 72 Section 38. Reserved. ... 72 Section 39. Reserved. ... 72 Section 40. Reserved. ... 72 Section 41. Reserved. ... 72 Section 42. Reserved. ... 72 Section 43. Reserved. ... 72 Section 44. Reserved. ... 72 Section 45. Reserved. ... 72 Section 46. Reserved. ... 72 Section 47. Reserved. ... 72
OF TREATED NON-DOMESTIC WASTEWATER
Section 48. General. ... 73 Section 49. Definitions Specific to Part E. ... 73 Section 50. Site Requirements. ... 73 Section 51. Pretreatment Water Quality Requirement. ... 75 Section 52. Reserved. ... 75 Section 53. Reserved. ... 75 Section 54. Reserved. ... 75
Section 55. Irrigation Water Quality. ... 75
Section 56. Effluent Quality. ... 77
Section 57. General. ... 81
Section 58. Sewage System Standards. ... 81
Section 59. Potable Water Supply Standards. ... 82
Section 60. Reserved. ... 84
Section 61. Reserved. ... 84
Section 62. Reserved. ... 84
Section 63. Reserved. ... 84
Section 64. Reserved. ... 84
Section 65. Reserved. ... 84
Section 66. Reserved. ... 84
Section 67. Reserved. ... 84
Section 68. Reserved. ... 84
Section 69. Reserved. ... 84
Section 70. Reserved. ... 84
Section 71. Authority and Purpose. ... 85
Section 72. Applicability. ... 85
Section 73. Definitions Specific to Part H. ... 86
Section 74. Compliance with Other Laws and Regulations. ... 88 Section 75. Compliance Period. ... 88 Section 76. Permits, Enforceability and Applications. ... 89 Section 77. Exclusions. ... 90 Section 78. General Management Practices. ... 90 Section 79. Site Isolation Requirements. ... 91 Section 80. Minimum Level of Wastewater Treatment. ... 92 Section 81. Treatment Reliability. ... 92 Section 82. Authorized Reuse. ... 92 Section 83. Monitoring. ... 93 Section 84. Noncompliance Actions, Reporting and Monitoring Requirements. ... 94 Section 85. Record Keeping. ... 94 Section 86. Reporting. ... 95 Section 87. Operation and Maintenance Manual. ... 95
These standards are promulgated pursuant to W. S. 35-11-101 through 3511-1207. Specifically, W. S. 35-11-302 requires the administrator to establish standards for the issuance of permits for construction, installation, or modification of any public water supply and sewerage system, treatment works, disposal system or other facility capable of causing or contributing to pollution.
The purpose of these standards is to:
(a) Ensure that the design and construction of sewerage systems, treatment works, disposal systems and other facilities capable of causing or contributing to pollution meet the purpose of the Environmental Quality Act.
(b) Prevent, reduce and eliminate pollution and enhance the waters of the State of Wyoming by ensuring design and construction of systems and facilities are capable of the required treatment and/or disposal and continued operation to protect the health, safety and welfare of the environment and its inhabitants.
These standards pertain only to permits required pursuant to Chapter III and IX, Wyoming Water Quality Rules and Regulations.
The design and construction standards included in these regulations are directed toward conventional wastewater and waste systems. These standards impose limiting values of design for which a construction, installation or modification permit application and plans and specifications can be evaluated by the Division.
The terms “shall” and “must” are used when practice is sufficiently standardized to permit specific delineation of requirements or when safeguarding public health or protection of water quality justifies such definite action. Other terms, such as “should”, “recommend”, and “preferred” indicate desirable procedures or methods which allow deviations provided the purpose of these regulations can be accomplished.
The applicant shall use the date referenced copy of other standards referred to in these regulations. Where no date is listed for the referenced standards, the standards used shall be those in effect when these regulations become effective.
The following definitions supplement those contained in W. S. 35-11-103 of the Wyoming Environmental Quality Act.
49 (a) “Affected land” means the area of land from which overburden is removed, or 50 upon which overburden, development waste rock or refuse is deposited, or both, access roads, 51 haul roads, mineral stockpiles, mill tailings, impoundment basins, and all other lands whose 52 natural state has been or will be disturbed as a result of the operations.
53 54 (b) “Campground” means a parcel or tract of land under the control of a person at 55 which sites are offered for the use of the public or members of an organization either free of 56 charge or for a fee, for the establishment of temporary living quarters for two or more recreational 57 units.
58 59 (c) “Commercial/industrial waste and wastewater facilities” means any facility 60 not defined as a municipal or single family residence facility.
61 62 (d) “Construction” shall encompass the materials used, installation procedures and 63 tolerances, and testing and disinfection requirements.
64 65 (e) “Feedlot” means the concentrated confinement of animals or poultry in pens or 66 houses for meat, milk, or egg production or the stabling of animals or poultry for a period of 45 67 days or more in a 12 month period when forage or crops are not grown in the area of 68 confinement.
69 70 (f) “Hazardous substance” means any matter of any description including 71 petroleum related products and radioactive material (substance) which, when discharged into any 72 waters of the state, presents an imminent and substantial hazard to public health or welfare. This 73 definition includes all materials (substances) so designated by the U. S. Environmental Protection 74 Agency in the Federal Register for March 13, 1978 (Part III), Water Programs, Hazardous 75 Substances.
76 77 (g) “Land application/treatment” means the application of wastes or wastewater to 78 the land at a predetermined rate for the purpose of disposal or treatment by any or all of the 79 following processes: degradation, plant uptake, assimilation or accumulation in the soil profile 80 from filtration.
81 (h) “Maximum daily demand” means the largest daily water use rate which would 82 occur during the calendar year.
83 84 (i) “Maximum hourly or peak hourly demand” means the largest water use rate 85 which would occur during any one hour during the year. The maximum hourly demand may or 86 may not occur during the maximum daily demand period.
87 88 (j) “Mobile home park” means a parcel or tract of land under the control of a 89 person upon which two (2) or more mobile homes are located on a continual or seasonal 90 nonrecreational basis, regardless of whether a charge is made therefore.
91 92 (k) “Off-channel” means the interception of a drainage way which collects runoff 93 only from disturbed areas.
94 95 (l) “On-channel” means the interception of a drainage way which collects runoff 96 from both disturbed and undisturbed areas.
97
98 (m) “Permanent pool level” means the elevation in a sedimentation pond or 99 sediment control structure below which the water will not be discharged by an outlet structure or 100 by pumping. 101 102 (n) “Pond/lagoon” means a manmade or natural basin which is intended for 103 containment, treatment or disposal of wastes or wastewater. 104 105 (o) “Rapid infiltration system” means a land treatment system in which treatment 106 is accomplished by the movement of large quantities of wastewater through a coarse or highly 107 permeable soil profile. 108 109 (p) “Recreational unit” means a tent or vehicular type structure, primarily designed 110 as temporary living quarters for recreational, camping, or travel use, which either has its own 111 motive power or is mounted on or drawn by a self-powered vehicle. A tent means a collapsible 112 shelter of canvas or other fabric stretched and sustained by a rigid structure(s) and used for 113 camping outdoors. 114 115 (q) “Seasonal high groundwater table” is the highest elevation reached by the 116 groundwater during the wet season of the year (usually spring or early summer). 117 118 (r) “Sedimentation control facility” means a pond or structure designed to capture 119 runoff from disturbed areas for the purpose of treating water for sediment and suspended solids 120 removal. 121 122 (s) “Slow rate land application system” means an irrigation system in which 123 wastewater treatment is achieved due to vegetative uptake and percolation of wastewater through 124 the soil profile by low application rates. 125 126 (t) “Sludge” is the accumulation of solids settled from wastewater in a septic tank, 127 aerobic unit, clarifier, or equivalent. 128 129 (u) “Soil” means all unconsolidated material overlaying bedrock. 130 131 (v) “Toxic characteristics (or wastes)” means those characteristics (or wastes) 132 which are due to the presence of: substances or combinations of substances including disease 133 causing agents which, after discharge and upon exposure, ingestions, inhalation or assimilation 134 into any environmentally significant organism, either directly from the environment or indirectly 135 by ingestion through food chains, may cause death, disease, behavioral abnormalities, cancer, 136 genetic malfunctions, physiological malfunctions (including malfunctions in reproduction) or 137 physical deformation in such organisms or their offspring. This definition shall include all 138 substances designated as toxic or hazardous by the U.S. Environmental Protection Agency in the 139 Federal Register for December 24, 1975, (Part IV), Water Programs, National Interim Primary 140 Drinking Water Regulations; Federal Register for May 19, 1980, (Section 261), Hazardous Waste 141 Management System: Identification and Listing of Hazardous Waste; and the Federal Register 142 for July 16, 1982, Part V, National Oil and Hazardous Substances Contingency Plan. 143 144 145 146
149 This section is provided to encourage new technology and equipment and provide a 150 process for evaluating and permitting designs which deviate from these regulations. The proposed 151 construction of facilities and processes not in compliance with these regulations will be permitted 152 provided that the facility, when constructed, can operate meeting the purpose of these regulations.
153 154 (a) Each application for a permit to construct a facility under this section shall be 155 evaluated on a case-by-case basis using the best available technology. The following information 156 should be included with the application:
157 158 (i) Data obtained from a full scale, comparable installation which demonstrates 159 the acceptability of the design and/or,
160 161 (ii) Data obtained from a pilot plant operated under the design condition for 162 a sufficient length of time to demonstrate the acceptability of the design and/or,
163 164 (iii) Data obtained from a theoretical evaluation of the design which 165 demonstrates a reasonable probability of the facility meeting the design objectives; and
166 167 (iv) An evaluation of the flexibility of making corrective changes to the 168 constructed facility in the event it does not function as planned.
169 170 (b) If an applicant wishes to construct a pilot plant to provide the data necessary to 171 show the design will meet the purpose of the act, a permit to construct must be obtained.
173 Section 6. Engineering Design Report.
174 175 (a) Scope and purpose. An engineering design report which describes existing 176 conditions, problems, and the proposed solution is required for each project.
177 178 (b) Sewerage systems. The engineering design report shall include:
179 180 (i) A description of the service area including scaled vicinity plan map(s) of 181 the project with regard to adjacent and proposed development, elevations, and topographic 182 features.
183 184 (ii) Current and projected average, maximum day and peak flows for the 185 design of the project, per capita design flows, extraneous flows, and industrial and/or commercial 186 waste flows.
187 188 (iii) Downstream impact on existing sewers, lift stations and treatment 189 facilities. This information shall include existing population, waste loads, existing flows and 190 capacity of downstream facilities.
191 192 (iv) A letter of acceptance from the municipality, sewer district, or owner of 193 any affected downstream sewerage, treatment or disposal facilities.
195 (c) Treatment works and disposal systems. The engineering design report shall 196 include: 197 198 (i) A description of the facility site and location, including scaled site plan 199 and: 200 (A) Present and projected facility property. 201 202 (B) Flood protection indicating predicted elevation of 25- and 100- 203 year flood stages. 204 205 (C) Present and proposed access. 206 207 (D) Distances from current habitation. 208 209 (E) Prevailing wind direction. 210 211 (F) Fencing and/or security. 212 213 (G) Topographic features and contours with indicated datum. 214 215 (H) Soil and subsurface geological characteristics. Location of soil 216 borings, rock elevations and groundwater elevations shall be indicated. Provide a soils 217 investigation report of the proposed site. 218 219 (ii) A detailed description of the service area for the project including scaled 220 plan showing land use and boundaries. 221 222 (iii) A detailed description of the disposal technique for effluent and solids. 223 For lagoons, indicate whether the discharge is continuous, seasonal, or nondischarging. 224 225 (iv) Effluent water quality considerations for design of the facility shall be 226 described to include: 227 228 (A) Surface discharge. An application shall be submitted to the 229 Water Quality Division for a National Pollution Discharge Elimination System Permit. 230 231 (B) Groundwater protection. Pursuant to Chapter VIII of the Water 232 Quality rules. 233 234 (v) Design conditions shall be described to include: 235 236 (A) Proposed effluent standards. 237 238 (B) Design population. 239 240 (C) Existing and projected flows and flow variations. 241 242 (D) Shock loads, with cause and frequency. 243
244 (E) Existing and projected wastewater characteristics including 245 BOD, suspended solids, and pH. 246 247 (F) Existing and projected flow, loads and characteristics of 248 industrial wastes and toxic Materials. 249 250 (G) Existing or proposed quantity and frequency of septage 251 discharges. 252 253 (H) Climate conditions at existing or proposed treatment facility site. 254 255 (I) Existing or proposed water supply. 256 257 (J) Theory of operation. 258 259 (K) Odor control features. 260 261 (L) Complete description of existing facilities. 262 263 (vi) Specific requirements of any pertinent approved Water Quality 264 Management Plan shall be included. 265
267 268 (a) All plans for sewerage works shall have a suitable title showing the following: 269 270 (i) Name of owner and location of project. 271 272 (ii) North arrow and drawing scale. 273 274 (iii) Name and seal or signature of the engineer. 275
276 Datum used shall be indicated. Plans shall contain a site plan of the proposed project with 277 topography and boundaries of the project.
278 279 (b) Sewers. Plans for interceptor sewers, outfall sewers, new collector systems, force 280 mains, sewer extensions, or any combination shall include:
281 282 (i) A detailed plan view at a legible scale of each sewer line showing all 283 existing and proposed streets, adjacent structures, physical features, existing and proposed 284 locations of utilities and a North arrow. The location and size of all sewer lines, manholes, 285 cleanouts, and other appurtenances shall be indicated. Pertinent elevations shall be indicated on 286 all appurtenances. 287
288 (ii) Profiles of all sewer lines shall be shown on the same sheet as the plan 289 view at legible horizontal and vertical scales, with a profile of existing and finished surfaces, 290 elevations of the sewer inverts at all manholes, and the slope of the sewer inverts at all manholes, 291 pipe size and material, and the slope of the sewer line. The location of all special features such as 292 inverted siphons, concrete encasements, casing pipes, elevated sewers, etc., shall be shown.
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(iii) Special detail drawings, scaled and dimensioned to show the following:
(A) Details of all sewer appurtenances such as manholes, cleanouts, inverted siphons, elevated sewers, encasements, casing pipes, force main thrust blocks, outfall structures, etc.
(B) The approximate bottom of the stream, the approximate elevation of the low and high-water levels, and other topographic features at all locations where the project is at streams or lakes.
(C) Cross section drawing of the sewer’s bedding.
(D) Additional features not otherwise covered by specifications.
(iv) Location of waterlines within 30 feet (9m) horizontally shall be shown on the plan. Water lines that intersect sewers shall be shown on the profile drawings. Public and/or private water wells within 30 feet (9m) of sewer lines shall be indicated on the plans.
(c) Pumping stations, treatment works and disposal systems. Plans shall be submitted showing the relation of the proposed project to the remainder of the system. Layouts and detail plans shall show the following:
(i) Site location and layout including topographic and physical features, proposed arrangement of pumping or treatment units, existing facilities, existing and proposed piping arrangements, access drive, power supply, fencing, embankments, outfall sewer, outfall structure, and receiving stream with direction of flow.
(ii) Schematic flow diagram(s) and hydraulic profile(s) for treatment works wastewater, sludge and effluent flows.
(iii) Plan and section view(s) of the wetwell and drywell of the pumping station with specific construction details, features and pertinent elevations.
(iv) Plan and section view(s) of each treatment facility process unit with specific construction details, features and pertinent elevations. Details of each unit should include, but are not limited to, inlet and outlet devices, baffles, valves, arrangement of automatic control devices, aeration equipment, motors, sludge scrapers, sludge disposal, electrical devices or other mechanical devices.
(d) Specifications. Technical specifications shall accompany the plans for new sewers, pump stations, treatment works, disposal systems, or additions/modifications to existing systems or facilities. Where plans are for extensions to sewer systems, the specifications may be omitted, provided it is stated that the work is to be constructed under specifications authorized by the Water Quality Division office. Specifications on file must conform to these regulations.
The specifications accompanying construction drawings shall include:
(i) Identification of construction materials.
342 343 (ii) The type, size, strength, operating characteristics, rating or requirements 344 for all mechanical and electrical equipment, including machinery, valves, piping, electrical 345 apparatus, wiring and meters; laboratory fixtures and equipment; operating tools; special 346 appurtenances; and chemicals where applicable. 347 348 (iii) Construction and installation procedure for materials and equipment. 349 350 (iv) Requirements and tests of materials and equipment to meet design 351 standards. 352 353 (v) Performance tests for operation of completed works and component 354 units.
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WORKS, AND DISPOSAL SYSTEMS
This part contains the minimum standards for the design and construction of sewerage systems, treatment works, and disposal systems for domestic and municipal wastewater. Soil absorption and land application systems are contained in other parts. All facilities shall comply with the purpose of this chapter.
(a) Separate sewers. Separate sewers shall be provided for collection of stormwater and wastewater. Roof, areaway, drive or foundation drains shall not be connected to sanitary sewers.
(b) Pipe materials.
(i) Wastewater characteristics. Pipe materials shall resist acid and alkaline solutions, organic solvents, and other wastewater constituents and environmental conditions encountered.
(ii) Pipe loadings. Pipe materials shall be chosen and the pipeline shall be designed to withstand all trench and superimposed surface live loads with a minimum factor of safety. Rigid pipes shall have a minimum factor of safety of 1.5, and flexible pipes shall have a minimum factor of safety of 1.25.
(iii) Soil characteristics. Pipe materials shall be chosen to resist corrosion due to aggressive soil characteristics by the soil it contacts. Iron or steel pipe shall be protected from corrosion with polyethylene encasement or cathodic protection.
(iv) Joints. Pipe joints shall be flexible, durable and designed to minimize infiltration/exfiltration and exclude roots.
(v) Performance tests. Piping shall be subjected to leakage tests. Leakage tests shall be infiltration, exfiltration, or air tests.
(A) Infiltration. Maximum of 200 gallons per inch diameter per mile per day (1200 liters/cm/km/day) with a minimum of two feet (0.6 m) of head over the top of the pipe.
(B) Exfiltration. Maximum of 200 gallons per inch diameter per mile per day (1200 liters/cm/km/day) with a minimum of two feet (0.6 m) of head over the top of the pipe.
(C) Air. Air tests shall conform to ASTM C-828-80. (D) Deflection. Maximum five percent deflection after flexible pipe is backfilled for 30 days. A mandrel of 95 percent of pipe diameter shall be used. No mechanical pulling of mandrel is permitted.
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(vi) Approved pipe material specifications. Type of commercial pipe approved for gravity sanitary systems include:
(A) Extra strength and standard strength vitrified clay pipe: ASTM C700-78a. (B) PVC sewer pipe and fittings: ASTM D3034-80, SDR35, ASTM F679-81, or ASTM F794-83. (C) ABS composite sewer pipe: ASTM D2680-80. (D) Reinforced plastic mortar pipe: ASTM D3262-81. (E) Asbestos cement nonpressure sewer pipe: ASTM C428-80. (F) Reinforced concrete sewer pipe: ASTM C76-82. (G) Concrete Sewer Pipe: ASTM C-14. (H) Ductile iron sewer pipe: ASTM A746-77.
Types of commercial pipe approved for pressure sanitary sewer systems include:
(I) PVC water pipe: ASTM D2241-80, or AWWA C900. (J) Asbestos cement pressure pipe: AWWA C400-80. (K) Ductile iron pipe: AWWA C151-81. (L) Glass Fiber-Reinforced Thermo-setting-Resin Pressure Pipe: AWWA C950-81.
(c) Collection piping design, construction and testing. A sewage collection line is any conduit that carries wastewater that originates from two or more separate buildings or from a single building that generates more than 2,000 gpd (7.6 m³/d) of average daily flow.
(i) Gravity system.
(A) Depth. Sewers shall be located to protect them from freezing and frost heave as prudently possible.
(B) Size. Sewers to be aligned straight shall be eight inch (20.3 cm) diameter or larger except six inch (15.2 cm) sewers may be used in cul-de-sacs, or other dead end locations where the sewer cannot be extended in the future. Eighteen-inch (45.7 cm) or larger sewers may be laid on curves. Lines shall be sized for 200 percent of maximum daily flow or more. In the absence of data deriving maximum daily flow, the chart on Figure 1-1 shall be used to deter mine maximum daily flow.
452 453 454 455
(C) Slope. Sewers shall be laid with uniform slope between manholes. Minimum slopes shall be:
| Sewer Size Inch (cm) | Minimum Slope in Feet Per 100 Feet (m/100 m) |
|---|---|
| 6 (15.2) | 0.60 |
| 8 (20.3) | 0.40 |
| 10 (25.4) | 0.28 |
| 12 (30.5) | 0.22 |
| 14 (35.6) | 0.17 |
| 15 (38.1) | 0.15 |
| 16 (40.6) | 0.14 |
| 18 (45.7) | 0.12 |
| 20 (50.8) | 0.11 |
| 21 (53.3) | 0.10 |
| 24 (61.0) | 0.08 |
| 27 (68.6) | 0.067 |
| 30 (76.2) | 0.058 |
| 33 (83.8) | 0.051 |
| 36 (91.4) | 0.046 |
456 457 458 459 460
Maximum slopes without the use of concrete anchors shall be 20 percent. The following spacing of concrete anchors shall apply to slopes greater than 20 percent:
| Slopes (percent) | Concrete Anchor |
|---|---|
| 20-35 | 36 ft (11 m) |
| 35-50 | 24 ft (7.3 m) |
| More than 50 | 16 ft (4.9 m) |
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(D) Velocity. Minimum velocities shall be 2 fps (0.6 mps) when flowing full. Velocities greater than 10 fps (3.0 mps) require special design considerations.
(E) Increasing size. All sewer pipe size changes shall be at manholes. Pipe size shall not be decreased in the direction of flow. The energy gradient line should be maintained when a smaller sewer joins a larger one.
(F) Excavation, bedding installation, backfill.
(I) Excavation. Trench width from the trench bottom to a point one foot above the top of the pipe shall be no less than the outside diameter of the pipe plus 8 inches (20.3 cm) but not more than 24 inches (61 cm) plus the pipe O.D. The trench bottom shall be excavated for the pipe bell. All rock shall be removed within six inches (15.2 cm) of pipe. The trench shall be dewatered for all work.
(II) Bedding. Bedding shall be designed in accordance with:
479 (1.) Rigid pipe. Types A, B, C (Water Pollution 480 Control Federation Manual of Practice No. 9) or ASTM C12-81. 481 482 (2.) Flexible pipe. Types I, II, III, ASTM D2321-74. 483 484 (III) Backfill. Backfill shall be performed without disturbing 485 pipe alignment. Backfill shall not contain debris, frozen material, unstable material, or large 486 clods. Stones greater than three inches (7.6 cm) in diameter shall not be placed within two feet 487 (0.6 m) of pipe. Compaction shall be to a density equal to or greater than the surrounding soil. 488 489 (ii) Force mains and pressure sewers. 490 491 (A) Depth. Force mains shall be located to protect them from 492 freezing and frost heave. 493 494 (B) Size. Force mains shall be four inches (10 cm) diameter or 495 greater. Pressure sewer collection system piping shall be one inch (2.4 cm) minimum. 496 497 (C) Velocity. Minimum velocity shall be 2.5 fps (0.76 mps). 498 499 (D) Air release. Air release facilities shall be provided at the high 500 point in the piping whenever the pipe crown elevation falls below the pipe invert elevation. 501 Access to air release manholes shall not be in traffic-ways. 502 503 (E) Cleanouts. Cleanouts shall be provided at 400 foot (122 m) 504 maximum spacing in pressure piping four-inch diameter or less. 505 506 (F) Pressure sewer systems. Pressure sewer collection systems shall 507 be preceded by grinder pumps or septic tanks. 508 509 (G) Pressure sewer collection system pumps. Pumps shall be 510 provided with isolation and check valves. If a septic tank is not provided before the pump, a 511 grinder pump shall be required. Pump holding sumps shall not be steel, iron, or coated metal. The 512 sump chamber shall be 50 gallon (189 liters) volume, minimum. 513 514 (iii) Service connections. A service connection is any conduit that carries 515 wastewater that is not defined as a sewage collection line. Service connections shall conform to 516 the requirements for sewage collection lines (Section 9(c)(i) and (ii)) with the following 517 modifications: 518 (A) Size: minimum size shall be four inches (10.2 cm). 519 520 (B) Slope: minimum slope shall be two feet/100 feet (2 m/100 m). 521 522 (C) Flow: flow shall be determined from a fixture unit count and the 523 sewage size based on flowing full. 524 525 (D) Connections: all service connections to sewage collection lines 526 shall be made with a wye or tee for new construction and a tapping saddle for connection to 527 existing collection lines.
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(d) Manholes and cleanouts.
(i) Location. Manholes shall be located at all changes in pipe size, vertical or horizontal alignment, pipe intersections, and the end of lines. Maximum spacing for various line sizes are as follows:
| Line Size (In) | (cm) | Maximum M.H. | Spacing |
|---|---|---|---|
| 15 or less | (38 or less) | 400 ft | 122 m |
| 16 - 30 | (40.6 - 76) | 500 ft | 152 m |
| 31 or more | (76 or more) | 600 ft | 183 m |
Terminal sewer cleanouts may be provided at the end of sewer lines if they are not more than 150 feet (45 m) from the nearest downstream manhole. The cleanout shall be constructed using 45 degree bends to the upturned pipe coming to the surface of the ground. The diameter of the cleanout shall be the same as the pipe size. Lampholes shall not be used.
(ii) Size. Minimum manhole interior size is four feet (1.2 m).
(iii) Drop manhole. Drop manholes must be constructed where the change in elevation between two lines is greater than 24 inches (0.6 m). Concrete encasement shall be provided around the drop pipe.
(iv) Invert. Manhole inverts shall be constructed to conform to the shape of the sewer. The bench shall drain to the invert. Connections to the manhole shall be watertight and allow differential settlement between the manhole and pipe. Minimum fillet height shall be one half of the pipe diameter.
(v) Cover. The manhole cover shall be suitable to withstand all loads, including impact loading without deformation, slip or rattle. The manhole cover shall be watertight in areas subject to flooding and a bolt-down type in areas subject to unauthorized dumping or vandals.
(vi) Steps. Access to manholes shall be with portable ladders, or with cast iron manhole steps spaced at 16 inches (40.6 cm) maximum.
(vii) Materials. Manholes shall be constructed watertight and durable using cast-in-place concrete, or precast concrete with gasketed joints. Where precast concrete bases are used, the first 12 inches (30 cm) of wall will be monolithically cast with the base.
(viii) Access. A 22 inch (56 cm) minimum diameter clear opening shall be provided on all manholes. All manholes shall be located to be accessible by motorized equipment for maintenance.
(e) Special structures.
(i) Inverted siphons. Inverted siphons shall have a minimum of two six-inch (15.2 cm) barrels. The inlet and outlet shall be arranged to cause only one pipe to be used during
572 normal flows. The minimum velocity shall be 3 fps (1 mps) at average flow, and occur at least 573 daily. The siphon shall be designed for flushing and maintenance.
574 575 (ii) Aerial crossings. Aerial crossings shall be designed to prevent freezing, 576 leaking, settlement, lateral movement, and damage from expansion/contraction. It shall be located 577 with proper vertical clearances for highway vehicles and the 100 year flood.
578 579 (iii) Stream crossings. Stream crossings shall be within 580 10° of the perpendicular direction of the stream. Pipe shall have a minimum cover of one foot in 581 rock, and three feet under other surfaces. The crossing shall be made with an inverted siphon or 582 without a grade change. Pipe materials shall be steel, cast iron, or ductile iron pipe.
583 584 (f) Potable water supply protection.
585 586 (i) Cross connections. There shall be no cross connections between sewer 587 lines and potable water lines.
588 589 (ii) Horizontal and vertical separation from water mains. Minimum 590 horizontal separation shall be ten feet (3 m) where the water main is less than 1.5 feet (0.46 m) 591 above the elevation of the sewer. Minimum vertical separation shall be 1.5 feet (0.46 m) at 592 crossing. Joints in sewers at crossing shall be located at least ten feet (3 m) from water mains. The 593 upper line of a crossing shall be specially supported. Where vertical and/or horizontal clearances 594 cannot be maintained, the sewer shall be placed in a separate conduit pipe.
595 596 Section 10. Pumping stations.
597 598 (a) Design conditions.
599 600 (i) Total dynamic head. The total dynamic head rating of pumping units 601 shall be based on pipe friction, pressure losses from piping entrances, exits, appurtenances 602 (bends, valves, etc.), and static head at the rated flow.
603 604 (ii) Grit. Where no grit removal is provided ahead of the pumping station, 605 equipment and piping design shall minimize the deleterious effects of grit in the sewage.
606 607 (iii) Screening. Screens or comminutors shall be provided ahead of pumps 608 where the average daily flow is in excess of 1.0 mgd (3,784 m3/d) to prevent solids larger than 2 609 ½ inches (6.4 cm) from entering the pump.
610 611 (iv) Minimum pump opening. Except for grinder pumps, raw sewage pumps 612 shall be capable of passing spheres of at least three inches (7.6 cm) in diameter. Pump suction and 613 discharge piping in all sewage and sludge services shall be no smaller than four inches in 614 diameter (10 cm).
615 616 (v) Pump cycle time. Intermittently operated pumps shall be designed to 617 start no more often than once every ten minutes at the minimum operating interval.
618
619 (vi) Removal of equipment. Pumping stations shall be designed to permit 620 removal of all items of equipment including pumps, valves, electrical and control equipment. 621 Equipment located in wetwells shall be removable without entering the wetwell.
622 623 (vii) Surge control. Piping systems shall be designed to withstand the 624 maximum possible surge (water hammer) from the pumping station, or adequate surge control 625 provided to protect the piping. Pressure relief valves are not acceptable surge control.
626 627 (viii) Net positive suction head. Pumps shall be selected so that the net positive 628 suction head required at maximum flow (NPSHR) is less than the NPSH available minus four feet 629 (1.2 m) based on the hydraulic conditions and altitude of the pumping station.
630 631 (ix) Uplift. The pumping station chambers shall resist hydrostatic uplift 632 pressures. Siting requirements.
633 634 (b) Siting requirements.
635 636 (i) Access. Pumping stations shall be located so that they are readily 637 accessible to operating and maintenance personnel at all times of day or night, and under all 638 weather conditions. Pumping stations shall be located off of traffic ways.
639 640 (ii) Flood protection. Pumping stations shall be designed so there is no 641 equipment or structural damage in the 100 year flood, and so the pumping station's operation is 642 uninterrupted by the 25 year flood.
643 644 (iii) Security. The pumping station shall be designed to discourage 645 unauthorized entry.
646 647 (c) Pumping station types.
648 649 (i) Dry wells.
650 651 (A) Access. Pumping station dry wells and equipment rooms shall be 652 accessible for equipment inspection, operation and maintenance. Ladder and stair dimensions, 653 locations of landings, and structural design shall comply with the Wyoming OHSA (1982). 654 Equipment shall be removable from pumping stations without making structural changes to the 655 station.
656 657 (B) Separation from wetwell. Dry wells and equipment rooms shall 658 be completely separated from wetwells with no hatches, untrapped drains, or other connecting 659 accessways.
660 661 (C) Dewatering. Dry pits and below-grade equipment rooms shall be 662 provided with sump pumps sized to remove infiltration of water during normal seepage and 663 leakage.
664 665 (ii) Wetwell design. Wetwells shall be designed to prevent vortexing and 666 unstable pump operation. Pumps shall be located below the minimum water level, except suction 667 lift pumps. Suction intakes shall be bell-mouthed. Provisions shall be made for isolating,
668 bypassing and/or dewatering portions of the wetwell for maintenance. Hopper walls of wetwells 669 shall be sloped at no less than 1.75 vertical to 1 horizontal.
670 671 (iii) Submersible pumping stations. Submersible pumping stations shall be 672 designed specifically for totally submerged operation and so that pumps may be readily removed 673 from the wetwell without dewatering the wetwell or disconnecting piping in the wetwell. 674 Submersible pumps shall have an adequate means of indicating motor seal failure. Electrical 675 equipment shall be suitable for Class 1, Division 1, Groups C and D hazardous environments, as 676 defined in the National Electrical Code (1982).
677 678 (iv) Suction lift. Pumping stations utilizing suction lift pumps shall have 679 adequate priming means to prime the pumps quickly and shall be designed for priming the pumps 680 when the water level in the wetwell is one foot (0.3 m) below the lead pump starting elevation in 681 the suction wetwell, and for maintaining prime when the wetwell level is one foot (0.3 m) below 682 the lead pump stopping level. Valving shall not be located in the wetwell.
683 684 (v) Pneumatic ejectors. Pneumatic ejectors shall be limited to design flows 685 equivalent to 25 residential connections. One standby compressor shall be provided.
686 687 (vi) Grinder pumps. Grinder pumps shall be limited to design flows 688 equivalent to 25 residential connections.
689 690 (d) Piping and valves.
691 692 (i) Suction.
693 694 (A) Suction intake. Suctions shall be located so the pump is below 695 the minimum water level. Suction intakes shall be bell-mouthed. Suction intakes shall be located 696 against the far wall from the wetwell inlet.
697 698 (ii) Piping.
699 700 (A) Size. Sewage and sludge piping shall be no smaller than four 701 inches (10.2 cm) diameter, except as required for metering, or where grinder pumps are provided.
702 703 (B) Velocity. Piping and pumping systems shall be designed to 704 maintain a minimum velocity of 2.5 fps (0.76 mps), and a maximum velocity of 5 fps (1.52 mps) 705 for suction piping.
706 707 (C) Design pressure. Piping shall be designed for the maximum 708 operating pressure and for the maximum value of any surges (water hammer) which may occur, 709 taking into account any surge protection provided.
710 711 (D) Restraints. Piping shall be blocked and otherwise restrained to 712 prevent damaging movement under the maximum anticipated pressure (including test pressure).
713 714 (E) Cleanouts. Cleanouts shall be provided in pump suctions.
715 716 (iii) Valves. Valves shall not be located in wetwells.
717 (A) Shutoff. Except on submersible pumps and suction lift pumps, a 718 shutoff valve shall be provided on the suction of all pumps. A shutoff valve shall be provided on 719 the discharge of all pumps, regardless of type or service.
720 721 (B) Check. All pumps shall be provided with a check valve located 722 between the pump and the discharge shutoff valve, except where arranged so that backflow is not 723 possible under normal operating conditions.
724 725 (C) Air release. Air release valves shall be provided at the high 726 points in piping whenever the pipe crown elevation falls below the pipe invert elevation. On 727 sewage lines, air or air and vacuum release valves shall be specifically designed for sewage 728 service.
729 730 (e) Reliability.
731 732 (i) Multiple units. Every pumping station shall have not less than two 733 pumping units. The number of units and their size shall be sufficient to permit pumping the 734 maximum design flow with the largest pumping unit out of service.
735 736 (ii) One of the following shall be provided:
737 738 (A) Alternative power source. Where the pumping station serves 739 more than 50 residential units, alternative power shall be provided. Alternative power shall be 740 permanently installed or portable engine generator sets, permanently installed or portable engine 741 driven pumps or a separate, independent utility source provided. Where manual starting is 742 required, sufficient storage shall be provided to allow notifying the operator and performing 743 whatever tasks are necessary to get the pumping station in service. Where permanently installed 744 engine driven equipment is provided, sufficient fuel shall be provided for at least eight hours 745 operation under the maximum flow condition. Where more than one pumping station is affected 746 by a power outage and portable equipment is planned for alternative power source, sufficient 747 portable equipment shall be provided to provide alternative power to all pumping stations under 748 maximum flow conditions.
749 750 (B) Generators. Generators shall be sized to permit starting the 751 largest pump in the pumping station with all other pumps except one running. If the generator is 752 not capable of starting all pumps simultaneously, suitable controls shall be provided to stagger the 753 pump starts to remain within the capabilities of the equipment. Generators shall be diesel-fired, 754 natural gas-fired or bottled gas-fired. The use of gasoline or digester gas-fired generators for 755 permanently installed standby service is unacceptable. Gasoline-fired portable generators are 756 acceptable.
757 758 (C) Engine driving pumps. Engine driven pumps shall be sized for 759 maximum design flow. Diesel, natural gas and bottled gas are acceptable fuels for portable 760 engines only. Digester gas is unacceptable for standby fuel. Quick connecting couplings shall be 761 provided for portable engine driven pumps.
762 763 (D) Storage. Wastewater storage may be provided in the form of 764 underground storage or surface ponds or tanks in lieu of alternative power supplies. Storage shall
765 be sized for the maximum anticipated power outage, but not less than 24 hours at average design 766 flow. Storage shall be water tight and arranged to drain back to the pumping station wetwell.
767 768 (f) Electrical.
769 770 (i) Equipment location. All electrical equipment, including motors, motor 771 starters and controls shall be located so as to be undamaged by the 100 year flood.
772 773 (ii) Controls. Controls shall include a separate start/stop device for each 774 pump or for each pumping position in the control sequence. Controls shall be arranged so that the 775 failure of any one control system component will affect only the operation of one pumping unit. 776 Manual override shall be provided for normal pump operating control.
777 778 (iii) Code requirements. All electrical work shall comply with the National 779 Electrical Code as adopted and amended by the Wyoming Department of Fire Prevention and 780 Electrical Safety. Electrical equipment in enclosed wetwells which may be subject to explosive 781 concentration of hazardous gases or flammable fluids, including all raw sewage wetwells, shall 782 comply with the NEC requirements for Class 1, Division 1, Groups C and D areas.
783 784 (iv) Alarms. An alarm system shall be provided for each pumping station. As 785 a minimum, alarms shall include high wetwell level and high water level in the dry well. For 786 pumping stations having a capacity of 0.5 mgd (1890 m3/d) or more, the alarm shall be 787 telemetered to a facility that is manned 24 hours a day. For pumping stations having a capacity of 788 0.5 mgd (1890 m3/d) or less, an audio and visual alarm shall be provided in a conspicuous 789 location.
790 791 (g) Safety.
792 793 (i) Ventilation. All accessible pumping station areas shall be ventilated. 794 Ventilation may be continuous or intermittent. If intermittent, ventilation in areas normally visited 795 by operating personnel shall be started automatically at not greater than 30 minute intervals. 796 Permanently installed dry well ventilation shall provide at least six air changes per hour if 797 continuous, and 12 air changes per hour if intermittent. Permanently installed wetwell ventilation 798 shall provide 12 complete air changes per hour if continuous, and 30 complete air changes per 799 hour if intermittent. Wetwell ventilation shall be positive pressure, forcing air into the wetwell 800 rather than exhaustion from it. All ventilation equipment shall be of a non-sparking design. 801 Intermittent ventilating equipment shall insure starting upon entry of operating personnel. 802 Wetwells may be ventilated by gravity means if normal access by operating personnel is 803 unnecessary. Wetwells that are accessed infrequently shall be designed to permit the use of 804 portable blowers that will exhaust the space and continue to supply fresh air during access 805 periods.
806 807 (ii) Hoists. Where required for removing equipment, hoists shall be rated for 808 not less than 50 percent more than the weight of the heaviest single item to be lifted by the hoist.
809 810 (iii) Lighting. Lighting levels shall be sufficient to permit safe operation and 811 maintenance of all equipment within the pumping station, but not less than 30 foot-candles. All 812 areas shall be lit in such a manner that the failure of one lighting fixture or lamp will not cause the 813 area to be completely dark.
814 (iv) Equipment guards. Provide shields to protect from rotating or moving 815 machinery.
816 817 (v) Warning signs. Provide warning signs for nonpotable water, electrical 818 hazards, chemical hazards, or other unsafe features. Warning signs shall be permanently attached 819 to the structure or appropriate equipment.
820 821 (vi) Safety. Comply with the Wyoming Occupational Health and Safety 822 Rules and Regulations.
823 824 Section 11. General Treatment Plant Considerations.
825 826 (a) Surface water protection. Discharges to surface waters shall meet or exceed 827 quality limitations in the National Pollution Discharge Elimination System Permit. Plant 828 configurations and piping shall be arranged to avoid the bypassing of process units that could 829 result in inadequately treated sewage reaching the receiving surface water.
830 831 (b) Groundwater protection. Seepage and/or discharge to groundwater shall comply 832 with Chapter VIII of the Water Quality Regulations. Plan configurations and piping shall be 833 arranged to avoid the bypassing of process units that could result in inadequately treated sewage 834 reaching the groundwater.
835 836 (c) Siting requirements.
837 838 (i) Isolation. Treatment facilities shall be located to minimize public and 839 private nuisances and health hazards on inhabited areas or residential areas. Where treatment 840 plant siting does potentially affect inhabited areas, appropriate measures to minimize nuisances or 841 hazards shall be incorporated in the design.
842 843 (ii) Flood protection. All treatment process structures, mechanical 844 equipment, and electrical equipment shall be protected from the 100 year flood. The treatment 845 facilities shall remain fully operational and accessible during the 25 year flood.
846 847 (d) Hydraulic and treatment reliability.
848 849 (i) Alternative power source. All treatment plants shall have an alternative 850 source of power to provide reliable pumping and disinfection of sewage if required. The 851 alternative source of power shall be sized to provide the capability to pump design maximum day 852 flow rates through the treatment process and to disinfect the sewage if necessary. Acceptable 853 alternative power sources include:
854 855 (A) A diesel, natural gas, or propane fueled engine generator.
856 857 (B) A second independent electrical supply.
858 859 (C) Storage of sewage and subsequent treatment
860 861 (ii) Bypass treatment units. Complete by-passing of treatment units is 862 prohibited. Provide means to bypass any duplicate process unit or single unit where adequate
863 downstream process capability is provided. Sewage shall be treated in parallel singular units and/or 864 subsequent processes.
865 866 (iii) Multiple units. For average design flows greater than 100,000 gpd (378 867 m³/d), more than one unit of each unit process shall be provided. For average design flows of 868 less than 100,000 gpd (378 m³/d), one unit of each unit process may be provided if electrical or 869 mechanical equipment or diffusers can be removed while the unit is in operation, or if the unit can 870 be compartmentalized to permit access. There shall be no provision to bypass the entire plant nor 871 shall bypass provisions be made that will allow inadequately treated sewage to reach the ground 872 or surface waters.
873 874 Where more than one parallel unit is provided, positive means of dividing the flow 875 proportionally between units shall be included (such as splitter weirs or valves and meters).
876 877 (iv) Multiple equipment. Mechanical process equipment shall be provided in 878 multiple units. All pumping functions shall include sufficient pumping capacity that the peak 879 flow can be pumped with the largest single unit not in service. Blowers and mechanical aerators 880 for process aeration shall include sufficient capacity that the maximum day design capacity can be 881 delivered with the largest single unit not in service. Other equipment shall have standby units 882 where their function is critical to the treatment process.
883 884 (e) Electrical.
885 886 (i) Equipment location. Service transformers and other critical electrical 887 equipment shall be located above the 100 year flood and above grade. Transformers shall be 888 located in a manner that they are remote from or protected by substantial barriers from traffic. 889 Motor controls shall be located in superstructures and in rooms that do not contain sewage, 890 chemical processes, or corrosive atmospheres.
891 892 (ii) Code requirements. All electrical work shall comply with the National 893 Electrical Code as enacted and amended by the Wyoming Department of Fire Prevention and 894 Electrical Safety. Areas in which the occurrence of explosive concentrations of hazardous gases or 895 flammable fluids can occur Class 1, groups C and D, Division 1 locations shall be designed for 896 hazardous locations in accordance with the National Electrical Code.
897 898 (f) Structural.
899 900 (i) Construction materials. Construction materials shall be selected, 901 apportioned, and/or protected to provide water tightness, corrosion protection, and resistance to 902 weather variations.
903 904 (ii) Coatings. Coatings used to protect structures, equipment and piping shall 905 be suitable for atmospheres containing hydrogen sulfide and volatile organics. Surfaces exposed 906 in chemical areas shall be protected from chemical attack. Concrete surfaces in confined spaces 907 containing sewage shall be protected. Paints containing lead or mercury shall not be used.
908 909 (iii) Geological conditions. Structural design shall consider the seismic zone, 910 groundwater and soil support. Soils investigations shall be made, or adequate previous soils 911 investigations shall be available to develop structural design.
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(g) Safety. The Wyoming Occupational Health and Safety Rules and Regulations shall be complied with. The following items shall also be provided:
(i) Instruction manuals. Instruction manuals shall be provided for all mechanical and electrical equipment describing operation, maintenance, and safety.
(ii) Handrails. In addition to all Wyoming OSHA requirements, barriers around treatment basins shall be provided.
(iii) Warning Signs. Provide warning signs for nonpotable water, electrical hazards, chemical hazards, or other unsafe features. Warning signs shall be permanently attached to the structure or appropriate equipment.
(iv) Equipment guards. Provide shields to protect from rotating or moving machinery.
(v) Lighting. Provisions shall be made to light walkways, paths, and other accessways around basins, in buildings and on the site. All areas shall be lit in a manner that the failure of one lighting fixture will not cause an area to be dark, or the loss of power will not cause a room or enclosed area to be dark.
(vi) Climate conditions. Design of facilities such as exposed stairs, walkways, and sidewalks shall include nonskid surfaces.
(h) Instrumentation.
(i) Location. A flow measuring device shall be provided for the plant effluent unless it is a mechanical plant where an influent flow measuring device will be acceptable.
(ii) Type. For plants having an average design flow of 50,000 gpd (189 m³/d) or more, the flow measuring device shall provide recording of instantaneous flow rate, enable calculation of average daily flow rate and have provisions for calibration and correction.
(iii) Controls. Automatic controls shall be designed to permit manual override.
(iv) Alarms. Conditions that may affect discharge quality or personnel or public safety shall be alarmed at an attended location.
(i) Sampling. Access shall be provided to sample untreated wastewater ahead of the treatment facilities prior to adding any process return flows, and sampling of the effluent after all treatment process units, but before discharge to the receiving stream. An automatic sampler that composites samples in proportion to the flow rate on the effluent shall be provided if required by the NPDES permit.
(j) Ventilation. All enclosed spaces shall be provided with forced ventilation, excepting pumping station wetwells, scum pits, anaerobic process units, and man-holes. In areas
961 where there are open sewage channels, wet pits exposed to the room or process units without gas 962 tight enclosures, ventilation shall be provided to maintain a higher pressure in the room than 963 atmospheric and shall provide 12 air changes per hour. In equipment rooms, ventilation shall be 964 provided to limit the temperature rise in the room to less than 15° F (8° C) above ambient, but not 965 less than six air changes per hour. Rooms housing chlorine storage and/or feeders shall have 966 provisions for exhausting the room contents in two minutes and continuous ventilation to provide 967 12 air changes per hour.
968 969 (k) Dewatering of treatment units. All treatment units, channels, housing screens, or 970 other embedded equipment, and wetwells shall be provided with drains or sumps that facilitate 971 draining the unit for access and maintenance. Drainage shall be to upstream process units. Basin 972 slabs shall be designed to successfully resist the hydrostatic uplift pressure or relief valves shall 973 be provided.
974 975 (l) Cold weather protection. All equipment including pumps, bar screens, grit 976 washers, electrical equipment and other equipment not required to be in or on open basins (such 977 as clarifier drives and surface aerators) shall be housed in heated, lighted, and ventilated 978 structures. Structure entrances shall be above grade. Piping shall be buried below frost level, 979 placed in heated structures, or provided with heat and insulated. Walkways shall be located away 980 from areas of spray and/or ice buildup.
981 982 (m) Chemical storage. All chemical storage shall be housed or buried. Areas 983 designated for storage of specific chemicals shall be separated from areas designated for other 984 reactive chemicals. Liquid storage containers shall be isolated from other portions of the structure 985 by a curb that will contain and/or drain ruptured tank contents. Concrete floors, walls and curbs in 986 chemical storage and feed areas shall be coated to protect the concrete from aggressive chemicals. 987 Floors in polymer feed and storage areas shall be provided with nonslip surfaces. Rooms for 988 chlorine storage and feed equipment shall be gas tight and be provided with entry from outdoors. 989 All toxic chemical storage areas shall be provided with lighting and ventilation that are switched 990 from outside the room, and windows to permit viewing the room from outside.
991 992 (n) Design capacities.
993 994 (i) Flow. In the absence of flow measurement information, the design 995 average daily flow shall be based on a per capita daily flow rate of 100 gallons (378 liters). 996 Allowances shall be made for return flows from digesters, sludge thickeners and the like, and the 997 infiltration and wet weather inflow into older sewer systems. Significant industrial waste flows 998 shall be added to the per capita flow rate.
999 1000 (ii) Organic loads. In the absence of wastewater strength data, domestic 1001 waste treatment design shall be based on a per capita daily BOD and suspended solids 1002 contribution of 0.22 lb (0.10 kg) and 0.25 lb (0.11 kg), respectively. The influence of sidestream 1003 return flows and significantly strong industrial wastes shall be considered and included in the 1004 design where applicable.
1006 Section 12. Pretreatment.
1008 (a) Flow equalization.
1010 (i) Storage requirements. Where mechanical plants experience large diurnal 1011 variations in flow rate which will cause mechanical, hydraulic, or biological process upsets, flow 1012 equalization shall be provided. 1013 1014 (ii) Location. Pretreatment facilities, such as bar screens, comminutors and 1015 grit chambers, and where possible, primary clarifiers should be located ahead of the equalization 1016 basin. 1017 1018 (iii) Drainage and cleaning. Provisions shall be made to isolate, drain and 1019 clean the basin(s). 1020 1021 (iv) Aeration and mixing. Aeration shall be sufficient to maintain a minimum 1022 of 2.0 mg/L of dissolved oxygen in the basin at all times. Air supply rates shall be a minimum of 1023 10 cfm/ 1,000 cubic feet (10 m3/min/1000 m3) of volume for primary treated wastewater and 20 1024 cfm/1,000 cubic feet (20 m3/min/1000 m3) of volume for raw or screened waste water. 1025 1026 (v) Controls. Controls shall be provided to control the flow rate from the 1027 flow equalization basin. Flow measurement devices shall be provided. 1028 1029 (b) Screens. 1030 1031 (i) Location. Coarse screens shall be the first unit in the treatment process. 1032 Screens shall be housed. The housing shall be heated and ventilated. Access shall be separated 1033 from other enclosed spaces. Housing shall be designed for hazardous location (National Electrical 1034 Code, Class 1, Groups C and D, Division 1 locations). 1035 1036 (ii) Capacity. The screen capacity shall be capable of handling the maximum 1037 anticipated peak hourly flow including inflow and infiltration. 1038 1039 (iii) Types. 1040 1041 (A) Mechanically cleaned. Bar screens shall be mechanically cleaned 1042 if the removal of the daily accumulation of screenings results in surging of the flow. Manually 1043 cleaned screens shall be provided in parallel channels to permit removal of the mechanically 1044 cleaned screen from service. Bars shall be between 45° and 90° measured from the horizontal. 1045 1046 (B) Manually cleaned. Manually cleaned bar screens shall be used 1047 for bypass of a mechanically cleaned screen or for treatment installations having an average 1048 design capacity of less than 100,000 gpd (378 m3/day). Bars shall be between 30° to 45° from the 1049 vertical. 1050 1051 (iv) Bar spacing. Clear spacing on mechanically cleaned bar screens shall 1052 range from 1/2 inch to 1 3/4 inches (1.27 cm to 4.45 cm). Manually cleaned screens shall have a 1053 range from one to 1 3/4 inches (2.54 cm to 4.45 cm) clear spacing. Coarse screens may have 1054 spacing greater than 1 3/4 inches (4.45 cm). 1055 1056 (v) Velocities. Maximum approach velocity at average flows for a 1057 mechanically cleaned screen shall be 3.0 fps (0.91 mps). Maximum velocity for a manually 1058 cleaned bar screen shall be 1.5 fps (0.46 mps). Minimum velocities shall be 1.25 fps (0.38 mps).
1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106
(vi) Channel. Channels shall be designed to eliminate deposition and permit draining. The channel shall contain a rock trap ahead of mechanically cleaned screens. Multiple channels shall be designed to allow uniform and equal flow to the screens. Slide gates shall be provided to permit isolating sections of channel containing screens.
(vii) Controls. Cleaning operation shall be controlled by one or several of the following methods.
(A) Timers. A timer to start the cleaning operation, and a device to stop the cleaning operation after one cycle.
(B) Differential head. Cleaning device starts and stops on differential head across screen.
(C) High level switch. Cleaning device starts on high level and runs for predetermined length of time.
All screens shall have manual override capability. All controls shall be suitable for use in hazardous location (National Electrical Code, Class 1, Groups C and D, Division 1 locations).
(viii) Handling. Screenings receptacles shall be designed to contain a minimum of one day's screenings. Manually cleaned bar screens shall include an easily accessible and safe working platform. All handling areas should be well drained.
(ix) Disposal. Screenings shall be disposed of in a manner approved by the Department of Environmental Quality, Solid Waste Management section. Grinding of screenings and return to the wastewater flow is not acceptable.
(c) Comminutors.
(i) Location. When used, comminutors shall be located downstream of a coarse screen. Where grit removal is provided, comminutors shall be located downstream.
(ii) Capacity. Comminution or screening capacity shall be adequate with the largest comminutor out of service.
(iii) Number of units. Wherever comminutors are used, a bypass, manually cleaned bar screen shall be installed.
(iv) Channel. Provide stop plates or similar devices to permit isolating a comminutor for maintenance. Provide drainage and washdown facilities. Where grit removal is not provided upstream, provide a gravel trap upstream of each comminutor.
(v) Bypass. An emergency bypass with a manually cleaned bar screen shall be provided. All flow exceeding the operating capacity of the comminutor(s) shall be automatically directed to the emergency bypass.
1107 (vi) Controls. The comminutor shall run continuously. All electrical controls 1108 shall be NEC Class 1, Groups C and D, Division 1 rated.
1109 1110 (d) Grit removal and disposal.
1111 1112 (i) Where required. Grit removal shall be provided either by providing for 1113 its accumulation in other process units or by removal in a specially designed basin. Where 1114 accumulation is provided in other process units, duplicate units shall be provided to permit 1115 removal of grit.
1116 1117 (ii) Location. Grit removal shall be placed after bar screens or racks, but 1118 before comminutors and other treatment units. Where grit removal facilities can be located at 1119 grade, they shall be upstream of raw sewage pumping stations. Grit basins may be located 1120 outdoors with proper precautions against freezing, but all grit conveying, washing and handling 1121 facilities shall be located indoors.
1122 1123 (iii) Capacity. Grit removal devices shall be designed to effectively remove 1124 grit at the peak instantaneous flow rate. The grit handling capacity shall be a minimum of 15 1125 cubic feet per million gallons (1.12 m³/10,000 m³).
1126 1127 (iv) Number of units. A minimum of one mechanically cleaned unit and a 1128 bypass pipe or channel shall be provided for plants serving separate sewers. Five hundred 1129 thousand gallons per day (500,000 gpd) (1891.5 m³/d) plants or smaller may have a manually 1130 cleaned unit and bypass. Plants larger than 1.0 mgd (3784 m³/d), shall have two mechanically 1131 cleaned units with capability to isolate each one.
1132 1133 (v) Type.
1134 1135 (A) Aerated.
1136 1137 (I) Air requirements. Air supply must be controllable and 1138 capable of varying from 10 to 40 cfm/1,000 cubic feet (10 to 40 m³/m³/1,000 m³) of basin. Air 1139 diffusers shall be located above the tank bottom and positioned for adequate mixing.
1140 1141 (II) Equipment requirements. The tank shall be sized for a 1142 three minute retention time at peak flows. Grit shall be collected to a hopper for removal by 60 or 1143 greater sloped sides or mechanical equipment. The inlet and outlet shall be designed to avoid 1144 shortcircuiting. Air diffusers shall be removable without taking the basin out of service.
1145 1146 (B) Gravity chamber. Horizontal channel grit basins shall have an 1147 outlet control weir and specially shaped channel to maintain velocities from 0.8 to 1.3 fps (0.24 to 1148 0.4 m/s) over the anticipated range of flows. Square basins shall be designed for an overflow rate 1149 of 30,000 gpd/sq ft (1220 m³/m³/d) at the peak instantaneous flow rate.
1150 1151 (vi) Method of grit removal. Grit removal facilities located in pits six feet 1152 (1.8 m) or deeper and for plants larger than 500,000 gpd (1891.5 m³/d) shall be provided with 1153 mechanical equipment for moving grit to ground level.
1155 Plants having an average design capacity less than 100,000 gpd (378 m³/d) may be 1156 provided with manually cleaned grit basins.
1157 1158 (vii) Drains. Each unit in the grit facility shall be capable of being dewatered.
1159 1160 (viii) Grit disposal. Grit disposal methods shall be approved by the Department 1161 of Environmental Quality, Solid Waste Management Office.
1162 1163 Section 13. Primary Treatment.
1164 1165 (a) Sedimentation.
1166 1167 (i) Number of basins. For plants having an average design capacity greater 1168 than 100,000 gpd (378.4 m³/d) and where primary settling is provided, multiple units capable of 1169 independent operation shall be provided.
1170 1171 (ii) Design parameters.
1172 1173 (A) Performance. Unless full-scale data is available, primary settling 1174 shall be assumed to remove one third of the influent BOD and 55 percent of the influent 1175 suspended solids. It is unacceptable to return waste activated sludge to the primary clarifier.
1176 1177 (B) Water depth. The minimum side water depth shall be seven feet 1178 (2.1 m).
1179 1180 (C) Surface overflow rates. Surface overflow rates shall not exceed 1181 1,000 gpd/sq ft (41 m³/m²d) of surface area at the average design flow nor 1,500 gpd/sq ft (61 1182 m³/m²d) of surface area at the maximum day flow rate. Maximum day flow is the highest flow 1183 over a 24 hour period that is projected to occur during the design year.
1184 1185 (D) Weir loading rates. Circular basins (or basins with center inlets) 1186 shall be provided with a full periphery weir. Rectangular basins shall be provided with end weirs 1187 that provide less than 80,000 gpd/ft (9,920 m³/m d) weir hydraulic loading at peak instantaneous 1188 flow rates.
1189 1190 (iii) Clarifier inlet and outlet.
1191 1192 (A) General. Clarifier inlet structures shall be designed to achieve the 1193 following:
1194 1195 (I) Dissipate the inlet kinetic energy.
1196 1197 (II) Distribute the flow evenly into the tank.
1198 1199 (III) Prevent short circuiting.
1200 1201 Inlet channels or piping shall be designed for minimum velocities of one fps (0.3 mps). 1202 Where minimum velocities are less, mixing, flushing or other means of resuspending solids shall 1203 be provided.
1204 Circular basins shall be provided with symmetrical baffling to distribute flow equally in 1205 all radial directions.
1206 1207 Rectangular basins shall be provided with inlet parts uniformly distributed along the 1208 entire end of the basin and shall be provided with baffles.
1209 1210 (B) Weirs. Weir plates shall be adjustable for leveling and sealed 1211 against the effluent channel.
1212 1213 (C) Baffles. Provide scum baffles at the water surface to intercept all 1214 floating materials and scum prior to the weir. Baffles should extend three inches (7.6 cm) above 1215 the weir plate elevation and eight inches (20.3 cm) below the water surface.
1216 1217 (D) Clarifier effluent channel.
1218 1219 (I) Size. The effluent channel shall be sized to prevent weir 1220 submergence at the peak hourly flow.
1221 1222 (E) Freeboard. The outer walls of sedimentation tanks shall extend at 1223 least six inches (0.15 m) above the surrounding ground and shall provide at least 12 inches (0.3 1224 m) of freeboard to the water surface. Where basin walls do not extend four feet (1.2 m) above the 1225 surrounding ground, a fence or suitable barrier to prevent debris from entering the basin shall be 1226 provided.
1227 1228 (F) Basin equipment and access. Provide walkways and accessways 1229 to collector drive units, effluent launders and manual skimmer. Handrail shall be provided.
1230 1231 (b) Fine screens.
1232 1233 (i) Number of units. A minimum of two units shall be provided. Multiple 1234 units shall be capable of independent operation. With the largest unit out of service, the remaining 1235 units shall be capable of passing the peak flow rate.
1236 1237 (ii) Flow distribution. Positive means of flow distribution shall be provided 1238 ahead of the screens to ensure even loading and hydraulic flows.
1239 1240 (iii) Design parameters.
1241 1242 (A) Performance. In the absence of pilot plant data, the removal 1243 efficiency of fine screens shall be assumed to be zero percent removal of BOD₅ and 15 percent 1244 removal of suspended solids.
1245 1246 (B) Preliminary treatment requirement. Prior to the fine screens, 1247 removal of large debris shall be provided by coarse screens. Comminution shall not be provided 1248 ahead of screens.
1249 1250 (iv) Screenings storage and disposal. Screens with openings of 0.10 inch (2.5 1251 mm) or more shall be disposed of directly to landfill in accordance with the requirements of the 1252 Department of Environmental Quality, Solid Waste Management Office. Screens with openings
1253 less than 0.10 inch (2.5 mm) shall discharge the screenings (primary sludge) to sludge handling 1254 system for organic stabilization.
1255 1256 (v) Cleaning and maintenance. Provide facilities to permit regular cleaning 1257 of screens with a high pressure, hot water or steam system.
1258 1259 (vi) Controls. For rotating screens, each screen or series of screens shall be 1260 provided with an overflow. An alarm shall be provided when overflowing.
1261 1262 (c) Sludge handling.
1263 1264 (i) Sludge removal. Mechanical sludge collection equipment is required for 1265 all primary settling basins. The sludge collection rake arms or flights and the drive assembly shall 1266 be designed to withstand the maximum anticipated loads and move sludge to the hopper.
1267 1268 (ii) Scum removal. Provide scum collection and removal facilities for all 1269 primary settling basins. Scum shall be removed from the liquid process and not returned.
1270 1271 (iii) Sludge hopper. The minimum side slope of the hopper shall be 1.7 1272 vertical to 1.0 horizontal. Hopper bottoms shall have a maximum dimension of two feet (0.61 m). 1273 The sludge removal pipe shall be flush with the hopper bottom, and have a minimum diameter of 1274 six inches (15.2 cm).
1275 1276 (iv) Scum box. The scum box shall be located outside and immediately 1277 adjacent to the scum collection point (beaching plate). The beaching plate shall be located on the 1278 opposite side of the basin from the prevailing wind. Provide for mixing the contents of the scum 1279 box, such as a mechanical mixer or air diffusion. Provide access and wash water for washing the 1280 scum box.
1281 1282 (v) Controls.
1283 1284 (A) Primary settling sludge facilities. Primary sludge and scum shall 1285 be removed using positive displacement pumps. Each basin shall have a separately activated and 1286 controlled pump. (The standby pumps may be shared by more than one basin.) Pumps shall be on 1287 timers and the pumps should be designed to initiate sludge removal two or more times per hour.
1288 1289 Include devices on the primary sludge piping for sampling the primary sludge flow.
1290 1291 (B) Primary screen sludge facilities. Where sludge pumping is 1292 provided, include a means to shut off the pump when insufficient material is being supplied to the 1293 pump suction. The controls for the pump shall be designed to match the pumping rate to quantity 1294 of sludge. Where conveyors are used, they shall run continuously and alarm when off.
1295 1296 Section 14. Activated Sludge.
1297 1298 (a) Pretreatment. Where primary clarification is not provided, screening of the raw 1299 sewage to remove debris larger than 3/4 inch (1.9 cm) shall be provided. The screened material 1300 shall not be returned to the plant process. Where primary clarifiers are not provided, cleanouts, 1301 grinders, or other similar provisions shall be made in the return sludge piping.
1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350
(b) Loading rates. Activated sludge systems shall be designed to accommodate peak day loadings at the design year. Permissible loadings are presented in the following table. Where raw sewage BOD5 is less than 200 mg/L, detention times may be reduced.
(i) Conventional, including complete mix, plug flow, step aeration
| Average Day | ||
|---|---|---|
| Detention (*) hrs. | Following primary clarifiers | 6 minimum |
| Without primary clarifiers | 9 minimum | |
| Organic Loading: | lb/1,000 cu ft/day (kg/1000 m³d) | 35 maximum (560 |
| MLSS, mg/L | 1,000 - 3,000 |
(ii) Contact stabilization.
| Detention (*) hrs, | ||
|---|---|---|
| Contact Zone | 0.5 - 3 | |
| Sludge Stabilization Zone | 6 minimum | |
| Average Day | ||
| Organic Loading () | lb/1,000 cu ft/day (kg/1000 m³d) | 50 (800) |
| MLSS, mg/L | ||
| Contact Zone | 1,000 - 3,000 | |
| Sludge Stabilization Zone | 5,000 - 10,000 |
(iii) Extended aeration, including oxidation ditch.
| Detention (*) hrs, | 16 minimum | |
|---|---|---|
| Organic Loading, | lb/1,000 cu ft/day | 15 maximum (240) |
| (kg/1000 m³d) | ||
| MLSS, mg/L | 1,000 - 3,000 |
(*) Based on average day raw sewage flow rate exclusive of recirculation flow.
() Based on contact zone and sludge stabilization zone combined.
(c) Number of basins. For all design average flows in excess of 0.1 mgd (378 m³/d), two or more aeration basins shall be provided. For flows less than 0.1 mgd (378 m³/d), one aeration basin may be provided if the aeration devices can be readily removed while the basin is in operation.
1351 (d) Configuration. The basin configuration shall promote mixing, transfer of oxygen, 1352 and minimize stagnant zones.
1353 1354 (e) Freeboard. The walls of the aeration shall extend above the normal water surface 1355 to provide a minimum freeboard as follows:
| Minimum Freeboard (*) | ||
|---|---|---|
| inches | cm | |
| 1359 Diffused air | 18 | 45.7 |
| 1360 Surface aeration | 48 | 121.9 |
| 1361 Submerged turbine | 18 | 45.7 |
| 1362 Brush aeration, less than 10 feet from aeration device | 48 | 121.9 |
| 1363 Brush aeration, 10 feet or more from aeration device | 18 | 45.7 |
| 1364 Surface aeration, where aeration | 36 | 91.40 |
| 1365 is 30 or more feet from basin wall |
1366 1367 (*) Vertical walls. For sloped walls, the runup effect shall be considered.
1368 1369 (f) Inlet and outlet conditions. Inlets may be submerged and shall be baffled or 1370 directed away from the outlet to minimize shortcircuiting. Outlets shall be of the overflow type to 1371 discourage buildup of foam and floatables on the aeration basins. Pipe and channels shall provide 1372 a minimum velocity of 0.5 fps (0.15 m/s).
1373 1374 (g) Aeration requirements.
1375 1376 (i) Carbonaceous BOD? . When it can be shown that nitrification will not 1377 occur in the activated sludge process, the aeration devices may be sized to meet only the 1378 carbonaceous oxygen demand. The oxygen provided by the aeration device shall be selected to be 1379 adequate for the projected maximum day loading. In the absence of other data, an oxygen 1380 requirement of two times the average design day BOD? to the aeration basin shall be used.
1381 1382 (ii) Nitrification. Where nitrification is required to meet the effluent 1383 requirements or where the process cannot be operated to prevent nitrification, the aeration 1384 requirements will be selected to provide oxygen for both carbonaceous BOD? and nitrification on 1385 the projected maximum day loading. In the absence of other data, an oxygen requirement of two 1386 times the average design day BOD5 plus 7.5 times the average day ammonia nitrogen to the 1387 aeration basin shall be used.
1388 1389 (iii) Minimum dissolved oxygen. Oxygen supply shall be selected to transfer 1390 the design quantity during the maximum day loading while maintaining an aeration basin 1391 dissolved oxygen of 2.0 mg/L. The oxygen supply shall be designed for the specific site 1392 considering all factors that affect oxygen transfer efficiency.
1393 1394 (h) Mechanical aeration. Mechanical surface aerators shall be designed to maintain 1395 all organics in suspension, enhance the oxygen transfer capability of the unit, and minimize mist 1396 and spray that escape the basin. Drive units shall be protected from freezing mist and spray.
1397 1398 (i) Diffused aeration.
1399
1400 (i) Diffuser requirements. The number and location of diffusers shall be 1401 selected to distribute the design air quantity for efficient aeration and mixing. Diffusers in a basin 1402 shall be grouped on control valves to permit varying the air supply to different parts of the basin. 1403 Oxygen transfer efficiencies used for design purposes shall be conservatively selected, based on 1404 experimentally determined transfer rates of generically similar diffusers. The effect of 1405 transferring oxygen to wastewater, in lieu of water, and the effect of altitude shall be considered. 1406 The aeration basin mid-depth shall be used to determine the oxygen saturation concentration. 1407 Differential head loss to individual diffuser inlets shall not be more than 0.2 psi (14 gm/cm2).
1408 1409 (ii) Blower requirements. Blowers shall be sized to provide the air 1410 requirements for the aeration basins and other plant uses of low pressure air. The inlet air to the 1411 blowers shall be filtered or otherwise conditioned to effectively remove dust and other particulate 1412 material. Removal of particulate material for fine bubble diffusers shall be designed for 95 1413 percent of 0.3 micron. Filters designed for blowers shall be easily replaceable. Blower intakes 1414 shall be located to avoid clogging from drifting snow. Blowers shall be housed. The housing shall 1415 be ventilated to prevent more than a 15° F (8° C) temperature rise with all blowers operating, 1416 excepting the standby blower. The housing, blowers, and blower piping shall be arranged to 1417 permit removal of individual blowers while all other blowers are operating. Noise attenuating 1418 materials shall be used in the building interior. Blower systems shall be designed to permit 1419 varying the volume of air delivered. Blower motors shall be of a size to operate the blower 1420 throughout the range of ambient air temperatures experienced at the plant site.
1421 1422 (j) Sludge recirculation and waste.
1423 1424 (i) Rates. Sludge recirculation from the secondary settling basin to the 1425 aeration basin shall be variable within 25 to 100 percent of the average design flow. Sludge 1426 wasting from the activated sludge process may be from the mixed liquor or the return sludge. 1427 Sludge wasting shall be variable to enable wasting ½ of the total system solids in one day to zero 1428 wasting.
1429 1430 (k) Equipment requirements.
1431 1432 (i) Return sludge. Return sludge pumping shall be variable. The return 1433 sludge rate from each secondary settling unit and the rate to each aeration basin shall be 1434 controllable. Pumps shall be housed in heated, ventilated space. The pump floor shall be sloped 1435 and drained. Valves shall permit isolating each pump. Pumps and piping shall be arranged to 1436 allow ready removal of each pump. Check valves shall be provided where backflow through the 1437 pump could occur. Check valves shall be located in the horizontal.
1438 1439 Pump suction and discharge shall be three inches (7.6 cm) minimum. Sludge piping shall 1440 be four inches (10.2 cm) or larger. Cleanouts and couplings shall be provided in sludge piping to 1441 enable cleaning the pipe or to remove pumping equipment. All pipe high points shall be provided 1442 with air releases. All sludge piping shall be metallic material. Should air lift pumps be used, the 1443 units shall be designed with a minimum of 80 percent static submergence.
1444 1445 (ii) Waste sludge. If separate waste sludge pumps are provided, the rate shall 1446 be controlled by timers or variable speed devices. Pumping units shall be housed in heated, 1447 ventilated space, with sloped and drained floors. Pump suction and discharge piping shall be three 1448 inches (7.6 cm) minimum. Sludge piping shall be four inches (10.2 cm) or larger, except short,
1449 easily removable sections that may be required to maintain velocities above one fps (0.3 mps), or 1450 for use in conjunction with meters.
1451 1452 (l) Metering.
1453 1454 (i) Return sludge. For treatment plants having an average day design 1455 capacity greater than 100,000 gpd (378 m³/d) the return sludge flow rate from each secondary 1456 settling unit and to each aeration basin shall be metered to indicate flow rate. Return sludge 1457 metering devices shall be suitable for liquids carrying grease and solids, and shall be accurate to 1458 within ±5 percent of the actual flow rate. Meters shall be readily field calibrated by plant 1459 personnel. Meters shall be arranged to avoid trapping air.
1460 1461 (ii) Waste sludge. For treatment plants having an average day design 1462 capacity greater than 100,000 gpd (378 m³/d), waste sludge flows shall be metered to indicate and 1463 totalize. Waste sludge meters shall meet the requirements described for return sludge meters.
1464 1465 (iii) Air flow. Low pressure air used for basin aeration and other plant uses 1466 shall be metered. Separate meters shall be used to indicate the flow rate to each aeration basin and 1467 to the ancillary uses made of the low pressure air. Indicators shall be located near the device used 1468 to control the air flow rate. Pressure gages shall be provided immediately downstream from each 1469 blower and immediately upstream of each aeration basin.
1470 1471 (m) Controls. Facilities for control shall be provided for:
1472 1473 (i) Control of flow split between parallel process units.
1474 1475 (ii) Control of return sludge flow rate to each aeration basin.
1476 1477 (iii) Control of waste sludge quantity.
1478 1479 (iv) Control of air flow rate to each aeration basin.
1480 1481 (v) Control of air distribution to different zones in aeration basin.
1482 1483 (vi) Control of energy imparted with mechanical aeration. Facilities for 1484 control shall include a meter or device to measure rate and a device to change the rate such as a 1485 valve or adjustable weir.
1486 1487 (n) Prefabricated treatment units. Prefabricated activated sludge units shall conform 1488 to the applicable requirements described.
1489 1490 (o) Ancillary facilities. Adequate nonpotable washdown water shall be provided 1491 around the aeration basins sludge pumping area and secondary settling basins. Sampling ports, 1492 pipes or other access shall be provided on aeration basin inlets, return sludge piping, waste sludge 1493 piping and secondary settling basins. Hoisting or other means of equipment removal shall be 1494 provided. All subgrade floors shall be drained.
1495 1496 1497
1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544
(a) Pretreatment and primary treatment requirements. Attached growth systems shall be preceded by primary settling or fine screening. If fine screening is provided, the screen size shall have 0.06 inch (1.5 mm) or smaller openings.
(b) Trickling filters.
(i) Loading rates. Applied organic loading rates on trickling filters, where not used in series with activated sludge, shall be limited to:
| Applied Liquid Rate to Surface of Filter | BOD Loading* | |||
|---|---|---|---|---|
| (gpm/sf) | (lpm/m) | (lb/1000ft³/d) | (kg/1000 m³/d) | |
| Rock Media | 0.1 | 4.07 | 10 | 160 |
| 0.2 | 8.15 | 12 | 192 | |
| 0.3 | 12.22 | 16 | 256 | |
| Plastic or Redwood Media | 20 | 320 |
*For more than a one-stage trickling filter, the volume of all stages shall be used.
(ii) Recirculation. Recirculated flow to stationary media attached growth systems shall be provided. Recirculated flow shall be sufficient to provide the following minimum wetting rates:
| Media | Minimum Wetting Rate | |
|---|---|---|
| (gpm/sf) | (lpm/m²) | |
| Rock | 0.1 | 4.07 |
| Plastic or redwood | 0.75 | 30.5 |
(iii) Media. Media may be rock or specially manufactured material made of redwood or plastic. Rocks shall be durable and free from thin, elongated, flat pieces and should have the following size distribution:
| Passing 6-inch (15.2 cm) screen | 100% by weight |
|---|---|
| Retained on 4-inch (10.2 cm) screen | 95 - 100% by weight |
Fabricated media shall be resistant to ultraviolet degradation, disintegration, erosion, aging, all common acids, alkalies, organic compounds, fungus and biological attack. Media shall be capable of supporting a man’s weight.
(iv) Flow distribution. Wastewater shall be applied to stationary media by a rotary distributor or a fixed nozzle distribution system that provides uniform distribution. Flow distribution between multiple units of stationary or rotating media systems shall be by weirs, meters and valves, or other positive flow split device.
1545 (v) Depth of media. Rock trickling filters depth shall be between 5 to 10 feet 1546 (1.52 to 3.04 m), and manufactured media filter depth shall be between 10 to 30 feet (3.05 to 9.15 1547 m).
1548 (vi) Underdrain system. The underdrainage system shall cover the entire floor 1549 of the filter. Inlet openings into the underdrains shall have an unsubmerged gross combined area 1550 equal to at least 15 percent of the surface area of the filter. Underdrains shall have a minimum 1551 slope of one percent.
1552 1553 Effluent channels shall be designed to maintain minimum velocity of two feet per second 1554 (0.61 mps). Drains, channels and pipe shall be designed to have maximum depth flow of 50 1555 percent.
1556 1557 (vii) Flushing. Provide valves and structurally capable walls to permit 1558 flooding rock media filters. Access shall be provided around the periphery of the underdrain 1559 system to allow flushing the underdrains.
1560 1561 (viii) Freeboard. The clearance between rotating distributor and the media 1562 shall be at least 18 inches (0.46 m). The surrounding wall shall extend 2.5 feet (0.76 m) above the 1563 distributor.
1564 1565 (ix) Ventilation. All trickling filters shall be provided with ventilation 1566 openings to the underdrain. Ventilation openings will be provided with dampers or other 1567 adjustable devices to permit adjusting the ventilation rate opening. Ventilation openings shall be a 1568 minimum of eight square feet (0.74 m²) per 1,000 lb (454 kg) BOD⁷⁄₂/day.
1569 1570 Forced ventilation providing 4,000 cfm (113 m³/min) per 1,000 lb (454 kg) BOD⁷⁄₂/day 1571 shall be provided for covered filters.
1572 1573 (c) Rotating biological contactors (RBC).
1574 1575 (i) Loading rates. The organic loading rate on the first stage of an RBC shall 1576 be limited to 140 lb BOD⁷⁄₂/1,000 cu ft (2240 kg/1,000 m³) of media per day. The organic loading 1577 rate on all stages of an RBC shall be limited to 45 lb/1,000 cu ft (720 kg/1,000 m³) of media for 1578 media having a specific surface area of 35 sq ft per cu ft (114.8 sq m/m³). When more than ½ of 1579 the media has a specific surface area of 50 sq ft per cu ft (164 sq m/m³), the organic loading may 1580 be increased to 50 lb/ 1,000 cu ft (800 kg/1,000 m³).
1581 1582 (ii) Number of stages. Rotating biological contactors shall be designed with 1583 a minimum of three stages in series. Baffles shall be provided between stages.
1584 1585 (iii) Velocities. The rotational speed of the contactors shall be designed to 1586 maintain at least two mg/L of dissolved oxygen in each stage at designed loading rates. Drive 1587 units shall provide a rotational speed of one rpm or more.
1588 1589 (iv) Draining. Provide drains from each contactor basin.
1590 1591 (v) Media materials. Media materials shall be special manufactured material 1592 suitable and durable for the rotating biological contactor process. Media shall be resistant to 1593 disintegration, ultraviolet degradation, erosion, aging, all common acids, alkalies, organic com
1594 pounds, fungus, and biological attack. Media shafts shall be designed for unbalanced loads and 1595 cycle fatigue.
1596 1597 (vi) Housing. The housing for the RBC'S shall be designed with openings or 1598 access to allow removal and replacement of entire shafts.
1599 1600 Section 16. Combination systems.
1601 1602 When more than one type of biological treatment process is used in series, the removal 1603 through each biological unit shall be calculated as if it were acting alone. No symbiotic effect will 1604 be included in the design calculation.
1605 1606 Pretreatment requirements for combinations of biological systems will be the same as for 1607 attached growth systems. Final settling and sludge handling will be the same as for activated 1608 sludge systems.
1609 1610 Section 17. Secondary settling.
1611 1612 (a) Secondary settling. Secondary settling is required after suspended growth and 1613 attached growth biological processes such as activated sludge, trickling filters and RBC's.
1614 1615 (b) Configuration. The largest dimension (either diameter or length) of a clarifier 1616 shall be 80 feet (24.4 m). Corner sweeps on circular equipment are not acceptable.
1617 1618 (c) Flow distribution. Positive flow splitting shall be provided ahead of multiple 1619 sedimentation basins to ensure proportional hydraulic flows and solid loadings to each basin. 1620 Flow splitting shall be achieved using positive means such as weirs or valves and meters.
1621 1622 (d) Clarifier inlet and outlet structures.
1623 1624 (i) Clarifier inlet structures shall be designed to dissipate the:
1625 1626 (A) Inlet kinetic energy. 1627 1628 (B) Distribute the flow evenly into the basin. 1629 1630 (C) Minimize hydraulic turbulence. 1631 1632 (D) Prevent short circuiting.
1633 1634 Inlet devices that promote flocculation are encouraged.
1635 1636 The inlet structure for rectangular tanks shall be the full width of the basin, for peripheral 1637 feed clarifiers it shall be the entire periphery, and for center feed basins it shall be at least 1638 20 percent of the tank diameter. Baffled scum relief ports shall be provided between the inlet 1639 structure and the clarifier.
1640
1641 (ii) Inlet conveyance pipe or channels shall be designed to maintain a 1642 minimum velocity of 0.5 fps (0.15 mps) at the design flow. Where channels provide less velocity, 1643 provide mixing, flushing, or other means of resuspending solids. 1644
1645 (iii) Clarifier outlet systems shall be designed to minimize vertical velocities 1646 and reduce the effect of density currents at the effluent weir. Weir level shall be adjustable. 1647
1648 (e) Freeboard. The outer walls of settling tanks shall extend at least six inches (0.15 1649 m) above the surrounding ground and provide at least 12 inches (0.3 m) of free board to the water 1650 surface. Where settling basin walls are less than four feet (1.22 m) above the surrounding ground, 1651 a fence or other debris barrier shall be provided on the wall. 1652
1653 (f) Design parameters. 1654
1655 (i) Surface overflow rates. 1656
1657 (A) Activated sludge. Settling basins following an activated sludge 1658 process shall be designed to both thicken the sludge and clarify the liquid flow entering the tanks. 1659 The overflow rate shall not exceed: 1660
| Design Flow | Peak Hourly Flow | |||
|---|---|---|---|---|
| gpd/ft2 | m3/m2/d | gpd/ft2 | m3/m2/d | |
| 1661 | Activated Sludge | 600 | 24.4 | 1,200 4 8.8 |
| 1662 | Separate | |||
| 1663 | Nitrification | 400 | 16.3 | 800 32.5 |
| 1664 |
1667 (B) Attached growth biological reactors. Overflow rates for settling 1668 basins following attached growth processes shall not exceed: 1669
| Design Flow | Peak Hourly Flow | |||
|---|---|---|---|---|
| gpd/ft2 | m3/m2/d | gpd/ft2 | m3/m2/d | |
| 1670 | Trickling Filters | |||
| 1671 | and RBC's | 800 | 32.5 | 1,200 48.8 |
| 1672 |
1675 (ii) Solids loadings. Solids loadings for settling basins following an activated 1676 sludge process shall not exceed: 1677
| Design Flow | Peak Hourly Flow | |||
|---|---|---|---|---|
| gpd/ft2 | m3/m2/d | gpd/ft2 | m3/m2/d | |
| 1678 | All Activated | |||
| 1679 | Sludge Processes | 28 | 136.7 | 50 244.1 |
| 1680 | Separate | |||
| 1681 | Nitrification | 25 | 122.1 | 40 195.3 |
| 1682 |
1685 (iii) Side water depth. Settling basins shall be deep enough to provide 1686 adequate distance between the sludge blanket and the effluent weirs to avoid disturbance of 1687 settled sludge. 1688
1689 The volume of the settling basin shall provide a minimum detention time of two hours at 1690 peak hourly flow rate. The peak hourly flow is the projected maximum flow over a one hour 1691 period during the design year. Peak hourly flow shall include all recycle flows entering clarifier. 1692
1693 (iv) Weir overflow rates and placement. Weir loading rates shall not exceed the 1694 following values:
| Design Flow | Peak Hourly Flow | |||
|---|---|---|---|---|
| gpd/ft2 | m3/m2/d | gpd/ft2 | m3/m2/d | |
| 1695 Launder and weir at | ||||
| 1696 outer wall | 12,000 | 149 | 20,000 | 248 |
| 1697 Launder and weir at | ||||
| 1699 | ||||
| 1700 3/4 point of radius or less | 18,000 | 223 | 36,000 | 446 |
| 1701 |
1702 1703 Where double weirs or serpentine type weirs are used, the weir length shall be computed 1704 as the length of the centerline of the launder. 1705
1706 (g) Baffles. Baffles shall be located at the water surface and in such a position as to 1707 intercept all floating materials (scum) prior to the weirs. Baffles shall extend three inches (7.6 1708 cm) above the weir level and 12 inches (0.3 m) below the water surface. In circular basins, the 1709 baffle shall be a minimum of six inches (0.15 m) inside the weir plate. In rectangular basins, the 1710 baffle shall extend across the width of the basin and upstream of the effluent weirs. 1711
1712 (h) Basin and equipment access. Walkways and access ways shall be provided to 1713 drive units, effluent launders, and manual scum devices. 1714
1715 (i) Sludge removal. Sludge collection and withdrawal equipment shall 1716 provide complete and continuous removal of settled sludge. Rapid sludge removal pipes shall 1717 return sludge to a well at the surface that enables visual observation of flow. Mechanical rakes 1718 shall move sludge to a hopper at the floor. The tip speed for circular mechanisms shall not exceed 1719 8 fpm (2.4 m/min) and straight line flight speed shall not exceed 1 fpm (0.3 m/min). 1720
1721 The return sludge removal pipes shall be at least four inches (10.2 cm) in diameter. The 1722 hydraulic differential between the clarifier water level and the return sludge level shall be 1723 sufficient to maintain a three fps (0.9 mps) velocity in each rapid return sludge withdrawal pipe. 1724 Each sludge withdrawal pipe shall be accessible for rodding or backflushing when the settling 1725 basin is in operation. 1726
1727 (ii) Scum removal. Provide effective baffling and scum collection and 1728 removal facilities for all secondary settling basins. Equipment shall include a mechanical, positive 1729 scum skimmer. 1730
1731 (iii) Sludge hopper. The minimum side slope of the hopper shall be 1.7 1732 vertical to 1.0 horizontal. Hopper bottoms shall have a maximum dimension of two feet (0.61 m). 1733 The sludge removal pipe should be flush with hopper bottom, and have a minimum diameter of 1734 six inches (0.15 m). 1735
1736 (iv) Scum box. Locate scum box outside settling tank and adjacent to the 1737 scum collection point. Provide method for mixing contents of scum box, such as air jets or
1738 surface wetting using waste sludge. Provide access and washwater for washing the scum box. The 1739 scum box shall be located on the side of the tank opposite the prevailing wind direction. 1740
1741 1742 Section 18. Lagoons.
1743 1744 (a) Design requirements.(ii) Wastewater loading rates.
1745 1746 (i) Location. Wastewater lagoons shall be located more than 500 feet (152 1747 m) from existing habitations.
1748 1749 (A) Facultative. The primary cells of a facultative (non-aerated) pond 1750 system shall be limited to a maximum BOD application of 40 lb/acre/day (44.8 kg/ha/d) at 1751 average design loading conditions.
1752 1753 (B) Aerated. Aerated lagoons shall be designed for an organic 1754 loading of less than 10 lb BOD /day/1,000 cu ft (160 kg/1,000 m³/d) for completely mixed 1755 systems, and less than two lb BOD5/day/1,000 cu ft (32 kg/1,000 m³/d) for aerated non- 1756 completely mixed systems. Aeration equipment shall be sized to maintain a minimum dissolved 1757 oxygen of two mg/L. Completely mixed systems are mixed to provide 1/4 hp/1000 cu ft 1758 mechanical mixing or 10 cfm/1000 cu ft of air mixing.
1759 1760 (C) Nonsurface water discharging ponds. Nonsurface water 1761 discharging ponds shall be designed on the basis of a water balance that considers evaporation 1762 and seepage. Water balance calculations shall be submitted with the plans and specifications. The 1763 BOD₅ loading for non discharging ponds shall not exceed 14 lb/acre/day (15.7 kg/ha/d) based on 1764 the average annual BOD₅.
1765 1766 (iii) Detention. Facultative lagoons shall be designed for a minimum detention 1767 time of 180 days.
1768 1769 The detention time in aerated lagoons shall be at least one and one half days for 1770 completely mixed primary cells, and seven days for non-completely mixed primary cells. 1771 Secondary cells shall increase the overall detention time to 30 days.
1772 1773 (iv) Storage. Nonsurface water discharging lagoons shall be designed to 1774 provide sufficient storage to retain all wastewater and rainfall during the wettest year of record 1775 during a ten year period of record. Seepage shall be controlled to maintain a minimum water 1776 depth of two feet (0.6 m) in the primary cell during the driest occurring year of a ten year period.
1777 1778 (v) Inlet.
1779 1780 (A) Location. The inlet pipe to the primary cell of a facultative 1781 lagoon shall be at least 30 feet (9.2 m) from any bank. It shall terminate at a point away from the 1782 outlet by a distance of at least equal to or greater than 2/3 of the longest lagoon dimension. In 1783 aerated systems, the influent line shall be located in the mixing zone of the aeration equipment.
1784 1785 (C) Apron. Provide a concrete apron at the inlet pipe termination 1786 with minimum dimensions of four feet by four feet (1.2 m by 1.2 m).
1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834
(D) Influent manhole. An influent man-hole shall be provided prior to the lagoons. The influent pipe in the influent manhole shall be at least six inches (0.15 m) above the normal operating water level of the primary lagoons.
(E) Flow distribution. Flow distribution for multiple primary cells shall be provided to effectively split hydraulic and solids proportionately.
(vi) Inlet and outlet structures.
(A) Location. Inlet and outlet structures shall be easily accessible by plant operators and located to minimize short circuiting within the cell. A level control structure shall be provided at the outlet of each cell.
(B) Level control. Provide controls to permit varying water levels between two feet and six feet (0.6 m to 1.8 m). Provide baffling at the outlet to prevent scum overflow. Multiple draw offs in the final cell shall be provided. At least one shall be located at the two foot (0.6 m) level.
(vii) Interconnecting piping.
(A) Location. Piping between lagoon cells shall connect to the preceding cell outlet control structure and discharge into the subsequent cell. The pipe shall discharge at least ten feet (3.05 m) from the toe of the slope on the lagoon bottom and shall terminate on the concrete apron that is at least four feet by four feet (1.2 m by 1.2 m).
(B) Elevation. The piping shall discharge at the floor of the lagoon.
(C) Material. Interconnecting piping shall be any acceptable pipe designed to resist low pressures and adequately protected from corrosion.
(b) Number of lagoons cells. A lagoon system with a total area greater than one acre (0.4 ha) shall have at least three cells in series. Smaller systems and nondischarge pond systems shall have at least two cells. The maximum size cell shall be 20 acres (8 ha).
(c) Lagoon configuration.
(i) Shape. Rectangular cells shall have a maximum length to width ratio of 5:1. No sharp corners nor dead-end coves are permitted.
(ii) Water depth. Facultative ponds shall be designed to have water depths of not less than two feet, nor more than six feet (0.61 m to 1.8 m). Aerated lagoons shall be designed to have water depths of not less than four feet nor more than 15 feet (1.2 m to 4.6 m).
(iii) Removal of lagoon cells from operation. Bypass piping for primary lagoon cells and aerated lagoon cells shall be provided.
1835 (iv) Lagoon freeboard. A minimum freeboard of two feet (0.6 m) shall be 1836 provided. Greater freeboard shall be provided for wave runup, where required.
1837 1838 (d) Construction requirements.
1839 1840 (i) Dike.
1841 1842 (A) Material. Dikes and embankments shall be of relatively 1843 impervious and stable material, and compacted to at least 95 percent of maximum density (ASTM 1844 D698-78). Embankment fill shall be free from organic material, rock larger than six inches (15.2 1845 cm) and construction debris. The area where the embankment is to be constructed shall be 1846 stripped of vegetation and roots.
1847 1848 (B) Top width. Dikes and embankments shall be constructed with 1849 minimum top width of eight feet (2.4 m).
1850 1851 (C) Slopes. Interior slopes shall be from three to four horizontal to 1852 one vertical, and shall be stable under varying water level conditions. Interior slopes that are 1853 surfaced with concrete paving or riprap may be constructed at slopes of two or more horizontal to 1854 one vertical. Exterior slopes shall be three or more horizontal to one vertical and shall prevent the 1855 entrance of surface water to the lagoon.
1856 1857 (ii) Seeding. Exterior slopes and interior slopes that are not riprapped shall 1858 be seeded with dryland grasses, unless another equivalent method for soil erosion control is 1859 provided.
1860 1861 (iii) Erosion control. Interior embankments except cells smaller than one acre 1862 shall be protected from wave action with riprap, paving, or other erosion resistant material, unless 1863 it is demonstrated that the ponds are sheltered from wind or where wind velocity is low and 1864 erosion will not occur.
1865 1866 (e) Lagoon sealing.
1867 1868 (i) Lagoon sealing. The seepage through the pond bottom and side walls 1869 shall not cause a violation of the groundwater standards as described in Chapter VIII (Quality 1870 Standards for Wyoming Groundwaters) of the Wyoming Department of Environmental Quality, 1871 Water Quality Rules and Regulations. Liners shall be required if the wastewater characteristics or 1872 site conditions will not insure the protection of the groundwater for which it is classified.
1873 1874 If the applicant cannot document that the facility poses no threat to groundwater and 1875 elects not to perform a subsurface study in accordance with Chapter III, Section 15 (a) and (b), 1876 then the groundwater shall be protected from contamination by the wastewater with a liner 1877 equivalent to three feet (1 m) of soil having a permeability of 10-7cm/sec or less. When an 1878 applicant performs a subsurface study, the requirements for the liner shall be determined based on 1879 the results of the study and the groundwater protection required. In no instance shall the 1880 maximum seepage rate exceed 1/8 inch per day (3.2 mm/day) in the primary pond(s).
1881 1882 Following construction of the lagoons, but prior to startup, a testing program shall be 1883 conducted to demonstrate the effectiveness of the sealing program. Should the testing program
1884 show the lagoon seal to be less effective than the above requirements, the seal shall be modified 1885 and retested until it succeeds.
1886 1887 (ii) Synthetic liners.
1888 1889 (A) Material. Synthetic liners shall be essentially impervious. The 1890 minimum lining thickness shall be 30 mils. The liner material shall be resistant to organic 1891 materials typical of sewage. The liner shall be resistant to sunlight or shall be covered with 12 1892 inches (30.5 cm) or more of soil at all locations including the lagoon bottom and side slopes.
1893 1894 (B) Liner stabilization. Where the seasonal high groundwater is 1895 above the bottom of the lagoon, the liner shall be stabilized to prevent it from rising.
1896 1897 (C) Appurtenances. A leak detection system and/or air release 1898 mechanism may be required.
1899 1900 (f) Aerated systems.
1901 1902 (i) Air requirements. Aerated ponds shall be designed to maintain 2 mg/L of 1903 dissolved oxygen or more throughout the pond contents.
1904 1905 (ii) Equipment requirements.
1906 1907 (A) Number. Surface aerators shall be provided at intervals of 200 1908 feet (61 m) or less. The lagoon shall be protected from erosion from the aeration equipment. At 1909 least two surface aerators or brush aerators shall be provided. With the largest unit out, the 1910 remaining units shall be capable of transferring the average day oxygen demand. Each diffused 1911 aeration system shall be provided with at least two blowers. With the largest blower out of 1912 service, the remainder shall be capable of supplying the design air flow rate.
1913 1914 (B) Removal. All equipment shall be accessible and removable from 1915 the edge of the lagoons. Provisions for dewatering shall be made for removal or repair of 1916 diffusers.
1917 1918 Section 19. Tertiary treatment systems.
1919 1920 (a) Phosphorus removal.
1921 1922 (i) Equipment requirements.
1923 1924 (A) Flash mixing. Chemical addition points shall be at points of high 1925 turbulence, such as Parshall flumes, hydraulic jumps, or separate mixing basins.
1926 1927 (B) Flocculation. Inlet and outlet design shall prevent short circuiting 1928 and turbulent destruction of floc. Minimum detention time shall be 20 minutes at the average 1929 design flow rate.
1930 1931 The velocity of flocculated water to settling basins shall be 0.5 to 1.5 fps (0.15 to 0.46 1932 mps). Changes in direction shall be with long radius elbows or curved channels.
1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979
(C) Chemical feed equipment. Storage shall be provided for at least 14 days of chemical supply. Liquid chemical storage tanks shall have a liquid level indicator, an overflow, and a receiving basin capable of holding 110 percent of the stored volume, or a drain capable of receiving accidental spills or overflows. Liquid chemical storage shall be provided with heat.
(b) Ammonia nitrogen reduction.
(i) Activated sludge. Ammonia nitrogen removal by activated sludge processes shall be designed with sludge retention time of at least 15 days and shall provide at least 16 hours of hydraulic detention time. Aeration requirements are described in Section 15.
(ii) Attached growth. Rock media trickling filters shall not be used for ammonia reduction. Fabricated media trickling filters used for ammonia shall be designed using a BOD loading of less than 14 lb/1000 cu ft (224 kg/1,000 m³) of media. Rotating biological contactors used for ammonia reduction shall be designed with hydraulic loadings less than 1.0 gpd/sq ft (40.7 L/m²/d) of media surface area. At least four stages shall be provided for ammonia nitrogen removal.
(iii) Lagoons. The design of facultative lagoons for ammonia removal shall provide a minimum detention of 180 days. Aerated lagoon systems may be designed for 160 days.
(c) Solids reduction.
(i) Filtration.
(A) Filtration rate. The maximum hydraulic loading for 24 inch (61 cm) or deeper media is 5 gpm/sq ft (292.5 m³/m²/d) of filter area. Filtration rates for shallower media shall be limited to 3gpm/sq ft (175 m³/m²d).
(B) Backwash requirements. Provide a minimum backwash rate of 20 gpm per square foot (1170 m³/m²/d) of filter bed for 24 inch (61 cm) or deeper media and 12 gpm/square foot (702 m³/m²/d) for shallower media; supply shall be filtered water. A rate of flow regulator on the main backwash line shall be provided. The total backwash water storage capacity shall be adequate for 20 minutes of continuous backwash.
Air scour or surface wash facilities are required. All surface wash devices shall be provided with a minimum flow rate of 0.5 gpm per sq ft (29.3 m³/m²d) water pressures of 50 psi (3.52 kg/cm²) or greater and use filtered water.
(C) Backwash waste handling and treatment. Waste filter backwash shall be collected in a surge tank and recycled to the treatment plant at a rate not to exceed ten percent of the average plant design flow rate. Waste backwash water may be returned to any point upstream of the biological treatment units.
1980 (D) Number of units. At least two units shall be provided. With one 1981 filter out of service, the remaining filters shall be capable of passing the maximum day design 1982 flow rate.
1983 1984 (E) Controls. Controls should be provided to remove a filter from 1985 service, backwash the filter, and return it to service. Where the control is automatic, there shall 1986 also be a means of manually overriding the operating equipment, including each valve essential to 1987 filter operation.
1988 1989 In addition, the following shall be provided:
1990 1991 (I) Sampling tap on filter influent and 1992 effluent.
1993 (II) Indicating and recording loss of head gauge.
1994 1995 (III) Flow rate indicating and control.
1996 1997 (IV) Means for feeding polymer as a filter aid at a controlled 1998 rate to filter influent water when chemically coagulated effluent is being filtered.
1999 2000 (ii) Microscreens.
2001 2002 (A) Pilot testing. Pilot plant testing on the fluid to be screened or 2003 data from other similar applications to demonstrate the suitability of the proposed filter fabric, 2004 fabric life, proposed loading rates, and other design criteria shall be provided.
2005 2006 (B) Loading rates. Flow equalization facilities shall be included in 2007 the design to moderate influent quality and flow variations.
2008 2009 The screening rate shall be selected to be compatible with available pilot plant test results 2010 and selected screen aperture, but shall not exceed 1.5 gpm/sq ft (87.8 m³/m²/d) for lagoon effluent 2011 or 5 gpm/sq ft (292.5 m³/m²/d) for activated sludge or attached growth effluents based on the 2012 maximum hydraulic flow rate applied to the units. The screening rate shall not exceed 0.75 lb/sq 2013 ft/day (3.7 kg/ m²/day). The effective screen area shall be considered the submerged screen 2014 surface area less the area of screen blocked by structural supports and fasteners.
2015 2016 (C) Backwash requirements. The backwash water shall be at least 2017 eight gpm/ linear foot (9 Lpm/m) of screen length at 60 psi (4.2 kg/cm² ), obtained from 2018 microscreened effluent.
2019 2020 (D) Controls. Each microscreen unit shall be provided with 2021 automatic drum speed controls with provisions for manual override.
2022 2023 (d) Rapid infiltration.
2024 2025 (i) Wastewater preapplication requirements. Rapid infiltration shall be 2026 preceded by settling or fine screening having 0.6 inch (1.5 mm) or smaller openings.
2027 2028 (ii) Hydraulic loading rates.
2029 2030 2031 2032 2033 2034 2035
(A) Permeability. Hydraulic capacity of the rapid infiltration site shall be based upon soil permeability, basin infiltration tests, or cylinder infiltrometer tests. Design loading rates based on these tests shall be as follows:
| Field Measurement | Annual Loading Rate |
|---|---|
| Basin infiltration test | 10% of minimum measure rate |
| Cylinder infiltrometer | 2% of minimum measured rate |
| Permeability | 5% of conductivity of most restricting soil layer |
2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073
(B) Precipitation. The total hydraulic load to the rapid infiltration basins includes precipitation. The one in ten year precipitation event should be used as the basis for design.
(C) Cold weather conditions. The design must recognize that drying rates, oxidation rates, nitrification and denitrification rates all decrease in cold weather. Cold weather loading rates shall be used to determine land requirements or cold weather storage shall be used. Provisions should be made to mow and disc basin surfaces in the fall to prevent ice from freezing the vegetation near the soil surface. Snow fences can be used to keep snow cover on the rapid infiltration basins to insulate the applied wastewater and soil.
(iii) Land requirements.
(A) Storage. A minimum of 14 days of storage shall be provided. Where applied sewage will be less than 4° C, 160 days of effluent storage shall be provided.
(B) Location. Rapid infiltration basins shall be located more than 500 feet (152 m) from existing habitation.
(iv) Basin size. Individual basin size shall not be greater than five acres (2.0 ha). Basin sizing should be based upon a maximum water depth of 12 inches (30.5 cm) in the rapid infiltration basins.
(v) Subsurface drainage. The capillary fringe above the groundwater mound shall not be closer than two feet (0.6 m) to the bottom of the infiltration basin. The distance to groundwater shall be at least five feet (1.5 m) below the soil surface within two days following wastewater application.
(vi) Groundwater monitoring. Refer to Chapter III, Section 15, of the regulations.
(e) Intermittent sand filters.
(i) Wastewater preapplications treatment requirements. Intermittent sand filters shall be preceded by settling or fine screens having 0.06 inch (1.5 mm) or smaller openings.
2074 (ii) Hydraulic loading rates. The maximum application rates shall be limited 2075 to:
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2079
2080
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2110
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2112
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2120
2121
(ii) Hydraulic loading rates. The maximum application rates shall be limited to:
| Maximum Application Rate | ||
|---|---|---|
| Source | gallons/acre/day | (m³/ha/d) |
| Primary Effluent | 130,000 | (200) |
| Secondary Effluent | 400,000 | (611) |
| Lagoon Effluent | 300,000 | (458) |
(iii) Media. The minimum sand depth shall be 24 inches (0.6 m). The sand must be free of cementing materials and clay or loam. The sand should have an effective size of not less than 0.2 mm and not greater than 0.5 mm, and a uniformity coefficient of less than 5.
Clean graded gravel shall be placed around the under drains and to a depth of at least 12 inches (0.3 m) over the top of the underdrains.
(iv) Underdrains. All intermittent sand filters shall be provided with underdrains. Underdrains shall be at least four inches (10.2 cm) in diameter. The under-drain pipe shall have a minimum slope of 5 feet per 1,000 feet (5 m/1,000 m).
The groundwater shall be at least two feet (0.6 m) below the bottom of the underdrain pipe.
(v) Number of units. Three or more filters shall be provided.
(vi) Dosing.
(A) In each dosage of an intermittent filter, the hydraulic capacity shall permit covering the bed to a depth of two inches (5 cm), within 20 minutes or less.
(a) Pumping.
(i) Design requirements. Sludge pumps shall be provided with a positive suction pressure at the pump impeller, rotor or plunger at dynamic conditions. Discharge pressure shall include static pressure difference and system friction losses based on the higher viscosity of the sludge than water.
(ii) Piping and valves.
(A) Minimum size. Sludge piping and valves shall at least four inches (10.2 cm) in diameter for pressure piping and six inches (15.2 cm) in diameter for gravity pipe. Pump suction and discharge shall not be less than three inches (6.6 cm) in diameter.
2122 (B) Minimum velocity. For sludge pipes larger than four inches 2123 (10.2 cm) in diameter, the minimum velocity shall be one fps (0.3 m/sec).
2124 2125 (b) Thickening.
2126 2127 (i) Types.
2128 2129 (A) Gravity. Gravity thickening shall only be used for primary 2130 sludge, digested primary sludge, lime sludge, or combinations of lime sludge, trickling filter 2131 humus and primary sludge.
2132 2133 (B) Dissolved air flotation. Dissolved air flotation shall only be used 2134 for combination of primary and biological sludges, waste biological sludges, and aluminum and 2135 iron salt sludges.
2136 2137 (ii) Design parameters.
2138 2139 (A) Influent solids concentration. The design for influent solids 2140 concentrations to gravity or flotation thickeners shall be 5,000 mg/L or less, except tertiary lime 2141 sludge.
2142 2143 (B) Operating schedule. Sludge thickening facilities shall have the 2144 capacity to treat the maximum amount of solids produced. Where intermittent operation is 2145 provided, sludge holding tanks ahead of and after the thickening process shall be provided.
2146 2147 (C) Solids loading. Solids loadings (solids applied to the thickener) 2148 on thickening devices shall be limited to the following maximum values.
2149
| Sludge Type | Gravity | Solids Loading lb/sq ft/day | Gravity | kg/m²/d Dissolved Air Flotation | |
|---|---|---|---|---|---|
| Dissolved Air Flotation | |||||
| Primary | 24 | NA | 117.2 | ||
| Digested primary | 20 | NA | 97.6 | ||
| Waste activated, without polymer with polymer | NA | 12 48 | 58.6 234.3 | ||
| Primary and trickling filter | 15 | -- | 73.2 | ||
| Anaerobically digested primary and activated | NA | NA | |||
| Primary and lime | 20 | NA | 97.6 | ||
| Tertiary lime | 60 | NA | 292.9 | ||
| Alum | NA | 12 | 58.6 |
2150 *NA - Not allowed.
2151
2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184
(D) Hydraulic loading. Gravity thickeners shall be designed for 400-800 gpd/ sq ft (16.3 m³/m²/d to 32.5 m³/m²/d) of surface area.
(iii) Number of units. Unless sludge storage capacity for three days is provided, there shall be at least two units of equal capacity provided for sludge thickening.
(iv) Controls. Controls for gravity and flotation sludge thickening operations shall include provision for influent flow rate control. Centrifuge thickening shall include adjustable manual controls for differential scroll speed, pool depth, and influent flow rate. Where chemical conditioning is required, chemical dosage rate shall have adjustable manual controls.
(v) Side stream waste characteristics. The flow, organic load, and solids load in the thickener return flow to the plant shall be included in the plant design loadings.
(vi) Odor control. Provisions shall be made for the continuous chlorination of gravity thickener influent. Any thickening installation for anaerobically digested sludge shall make provisions for enclosing zones where the sludge or decant is exposed to atmosphere, exhausting the zone at an adequate rate to prevent escape of gas, and treating the exhaust air for removal of odor causing agents.
(c) Aerobic digestion.
(i) Solids retention time. Solids shall be retained in the aerobic digester for 30 days for primary sludge and 20 days for waste sludge from conventional activated sludge systems. Waste activated sludge from extended aeration systems shall be retained for a minimum of 10 days.
(ii) Mixing and aeration requirements. Aeration requirements shall include the oxygen requirements for BOD stabilization, nitrification of ammonia nitrogen in the sludge, and nitrification of organic nitrogen in raw sewage solids and biological solids. A minimum dissolved oxygen of 2 mg/l shall be maintained. Minimum aeration requirements shall be:
| Sludge | CFM/1,000 lb solids/day | m³/min/1,000 kg/d |
|---|---|---|
| Extended Aeration | 300 | 18.7 |
| Conventional Activated Sludge | 800 | 50.0 |
| Primary Sludge | 2,100 | 131.0 |
The aerobic digester aeration shall be provided with nonclog diffused aeration. Mechanical surface aerators shall not be allowed. Aeration provisions shall be a minimum of 30 cfm/1,000 cu ft (30 m³/min/1,000 m³) of volume.
(iii) Number of digesters. Where aerobic digesters are used, two or more shall be provided for treatment plants having an average design capacity of 100,000 gpd or more. Multiple aerobic digesters shall be arranged to permit either parallel or series operation.
(iv) Supernatant removal and disposal. Supernatant shall be returned prior to the influent of the biological treatment process.
2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244
(d) Anaerobic digestion.
(i) Sludge characteristics. The minimum sludge concentration for feed to anaerobic digesters is four percent.
(ii) Number of digesters. Two or more digesters shall be provided for treatment plants having an average design capacity of 100,000 gpd (378.4 m³/d) or more.
(iii) Design requirements.
(A) Temperature. Primary anaerobic digesters shall be heated to provide a minimum temperature of 95°F (35°C). Controls shall maintain the digester temperature within ±5°F (±2° C).
(B) Mixing equipment. Digester mixing shall, as a minimum, provide control of scum accumulation at the gas/liquid interface. Mixing that is designed for increasing the effectiveness of the digester and thereby reducing detention time shall mix the entire tank contents. Mixing devices and their application rate that will be considered to provide high rate digestion are:
| Volume | Per 1,000 cf | Per 1,000 m³ |
|---|---|---|
| Slow speed turbine mixers | 0.25 hp | 6.7 kw |
| Draft tube mechanical mixers | 0.40 hp | 14.1 kw |
| External pumps and jet nozzles | 500 gpm | 66.7 m³/m |
| Gas mixing applied at bottom of digester | 10 cfm | 10 m³/m |
Less mixing may be provided; however, longer solids retention times than described below shall be required.
(C) Solids retention time. The minimum solids retention time for heated, primary digesters are:
| Unmixed | Completely mixed |
|---|---|
| 30 days | 10 days |
Solids retention time shall be the same as liquid retention time in the primary digester where waste activated sludge is anaerobically digested.
(D) Volatile solids loading. As an alternative design basis to solids retention time, heated primary digesters may be designed for the following maximum volatile solids loading:
| Unmixed |
|---|
| 0.1 lb/ft³/day (1.6 kg/m³/d) |
| Completely mixed |
|---|
| 0.3 lb/ft³/day (4.8 kg/m³/d) |
2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293
(iv) Sludge piping.
(A) Inlet. Except in completely mixed digesters, multiple inlets shall be provided. The piping shall provide the opportunity to heat undigested sludge prior to entering the digester.
(B) Sludge withdrawal. Except in completely mixed digesters, multiple withdrawal pipes shall be provided. One or more withdrawal pipes shall be from the digester floor.
(C) Supernatant withdrawal. The design basis for facilities using digesters for waste activated sludge shall assume no supernatant withdrawal. Piping for supernatant withdrawal may be provided. A minimum of three supernatant withdrawal levels shall be provided otherwise.
(v) Gas system. All portions of the gas system, including the space above the tank liquor, storage facilities, and piping shall be designed to be under greater than atmospheric pressure at all times.
(A) Piping. Gas piping shall be 2.5 inches (6.4 cm) diameter or greater. Piping from the digester shall be provided with a flame trap. Piping shall slope to condensate traps. Float controlled condensate traps are not permitted.
(B) Safety equipment. All necessary safety equipment shall be included. Pressure and vacuum relief valves, flame traps and other safety equipment shall be provided. Gas safety equipment and gas compressors shall be housed in a separate room with an exterior entrance.
(C) Metering. A gas meter with bypass shall be provided for measurement of total gas production.
(vi) Heating equipment. Sludge and digester contents shall be heated with an external heat exchanger. Where sludge is heated using digester gas, an auxiliary fuel supply shall be provided. Boilers using digester gas shall be designed to minimize corrosion and to facilitate burner replacement. All digester gas that is not beneficially used shall be incinerated in a waste gas burner.
(vii) Access. The roof of the digester and the top sidewall shall be provided with sealed access hatches.
(viii) Sampling. One and one-half inches (3.8 cm) or larger sampling ports shall be provided for inlet sludge, effluent sludge, supernatant and digester contents.
(ix) Supernatant disposal. Supernatant from secondary digesters or from subsequent thickening or dewatering facilities for digested sludge shall be treated independently or returned immediately preceding the biological process. Supernatant shall not be returned to the primary clarifier.
2294 (e) Dewatering.
2296 (i) Mechanical dewatering. Where provided, mechanical dewatering 2297 facilities shall include storage tanks for liquid sludge and shall provide for reliable use.
2298 2299 (ii) Drying beds.
2300 2301 (A) Gravity. Drying beds may be strictly evaporation or evaporation 2302 - percolation. Evaporation - percolation beds shall be provided with graded gravel and sand beds 2303 over perforated underdrain pipe. Evaporation beds shall be designed for the application of 1.5 feet 2304 (0.46 m) of sludge per year. Evaporation - percolation beds shall be designed for the application 2305 of four feet (1.2 m) of sludge per year. Storage of sludge in the beds or in separate basins shall 2306 provide 180 days of capacity. Percolate shall be returned to the plant ahead of the biological 2307 treatment process.
2308 2309 (B) Vacuum. The bed area for vacuum assisted open drying beds 2310 shall be based on the application of no more than 40 feet ( 12.2 m) of liquid per year. If the beds 2311 are housed, the bed area shall be based on the application of 80 feet (24.4 m) per year. Where 2312 beds are not housed, sludge storage shall be provided for 180 days of capacity. Polymer 2313 conditioning, chemical feed, chemical storage and facilities for mixing the polymer with the 2314 sludge shall be provided. Vacuum pumps, sump pumps, chemical feed equipment and motor 2315 control equipment shall be housed.
2316 2317 (iii) Filtrate disposal. Filtrate, centrate or underdrain liquid shall be returned 2318 to a point upstream of the biological treatment process. Centrate or filtrate shall not be returned 2319 upstream of the primary clarifier.
2320 2321 (f) Disposal.
2322 2323 (i) Degree of stabilization.
2324 2325 (A) Land application. Sludges shall be stabilized. Sludges that are to 2326 be used on public lands that are accessed by the public (parks, golf courses, cemeteries) or 2327 sludges that are to be made available to the public shall be composted or stabilized and stored for 2328 a period of at least one year. Sludges that are to be incorporated into the land shall be stabilized.
2329 2330 "Stabilized sludge" shall have reduced organic content and reduced pathogenic content. 2331 Stabilized sludge shall have less than 60 lb of BOD₅ per 1,000 lb (60 kg/1,000 kg) of dry weight 2332 sludge solids.
2333 2334 (B) Landfill. Sludge processed for incorporation into a landfill shall 2335 be (1) a solid or semisolid material that will not release water upon standing, and (2) has been 2336 subjected to anaerobic or aerobic digestion, or chemically treated with lime to a pH of 12.0 or 2337 chemically treated with chlorine to a free chlorine residual. Waiver of this requirement must be 2338 obtained from the Solid Waste Management Section of the Department of Environmental Quality.
2339 2340 (ii) Storage. Sludge storage shall be provided in lined earthen lagoons or 2341 structural tanks. The lagoon lining shall be designed to protect the groundwater pursuant to the 2342 requirements of Chapter VIII of the Water Quality Divisions rules and regulations. Sludge storage
2343 volume shall be sufficiently large to provide for independent operation of the sludge dewatering 2344 or disposal facilities from preceding liquid or sludge processes. 2345
2347
2348 (a) Chlorination/dechlorination. 2349
2350 (i) Chlorination. The disinfection capacity shall be sized to provide the 2351 coliform concentrations required by the discharge permit. Feeders shall be sized to provide the 2352 minimum dosage at the minimum flow rate and to the maximum dosage at the maximum flow 2353 rate. 2354
2355 (ii) Dechlorination. Dechlorination feeders shall be sized for the final 2356 effluent dechlorination dosage required by the discharge permit requirements. 2357
2358 (iii) Chlorination. 2359
2360 (A) Number of units. Feeders shall be able to supply, at all times, the 2361 necessary amounts of chemical at an accurate rate (±3%) throughout the range of feed. The 2362 number of units shall provide capacity for effluent disinfection with the largest unit out of service 2363 and a separate feeder or feeders for ancillary uses, such as prechlorination or intermediate process 2364 control chlorination. The number of feeders shall be selected to permit feeding chemicals over the 2365 range of required dosage while only varying a single feeder over a 10:1 range. 2366
2367 (B) Chemical storage. Chlorine shall be stored in a heated, ventilated 2368 space. Space shall provide at least 30 days of chemical supply, convenient and efficient handling, 2369 and dry conditions. Cylinders or other containers of chlorine gas should be isolated from 2370 operating areas and restrained in position to prevent upset. 2371
2372 (C) Piping. Piping systems carrying gaseous or liquid chlorine shall 2373 be schedule 80 black steel pipe with forged steel fittings. Bushings shall not be used. Vacuum 2374 piping for gaseous chlorine may be polyethylene tubing. 2375
2376 Gas piping between the chlorine pressure reducing valve of the chlorinator and the 2377 ejector shall be PVC or polyethylene. Piping for aqueous solutions of chlorine beyond the ejector 2378 shall be PVC, fiberglass, or steel pipe lined with PVC or saran. 2379
2380 (D) Maximum withdrawal. The maximum withdrawal rate of 2381 gaseous chlorine shall be limited to 40 lbs/day (18.1 kg/day) for 100 or 150 lb (45.4 or 68.0 kg) 2382 cylinders and 400 lbs/day (181 kg/day) for 2,000 lb (907 kg) cylinders, unless chlorine 2383 evaporators are used. 2384
2385 (iv) Dechlorination. 2386
2387 (A) Number of units. Dechlorination equipment shall be provided to 2388 permit feeding the design dosage with the largest unit out of service. Feeders shall be sized for a 2389 10:1 feed range. 2390
2391 (B) Chemical storage. Chemical storage shall be in a heated, 2392 ventilated room, separate from chlorine cylinder storage. Provisions for heating the storage area 2393 or the S0 cylinders shall be provided. Where used, bin storage shall be provided with desiccated 2394 vents.
2395 2396 (C) Piping. Piping for liquid or gaseous S0 shall be schedule 80 2397 black steel pipe with forged steel fittings. Bushings shall not be used. Piping for aqueous 2398 solutions of dechlorination chemicals shall be PVC, fiber glass, or steel pipe lined with PVC or 2399 saran. All valves for liquid and gaseous sulfur dioxide shall be as approved by the Chlorine 2400 Institute. Valves for aqueous solution of dechlorination chemicals shall be PVC or saran lined.
2401 2402 (D) Maximum withdrawal.
2403 2404 (I) The maximum withdrawal rate for sulfur dioxide from 2405 2,000 lb (907 kg) cylinders shall be 200 lb (90.7 kg) per day, unless sulfur dioxide evaporators 2406 are used.
2407 2408 (v) Makeup water. Water used for dissolving dry chemicals, diluting liquid 2409 chemicals or operating chlorine or S0 injectors shall be chlorinated and strained for filtered (65 2410 mesh) final effluent or potable water. Where potable water is used, backflow prevention shall be 2411 achieved by (a) a 6 inch (15.2 cm) air gap between the potable water supply pipe and the 2412 maximum water level of a receiving tank; or (b) an approved reduced pressure zone backflow 2413 preventer.
2414 2415 (vi) Mixing requirements. The feed point for chlorination or dechlorination 2416 chemical shall be at a location of high turbulence. At points of critical flow, specially designed 2417 static tube mixers or artificial mixing are required.
2418 2419 (vii) Contact basins.
2420 2421 (A) Detention time. The chlorine contact period shall provide a 2422 minimum of 15 minutes contact time at the peak hour design flow. The contact period shall be 2423 from the point of chemical injection into the flow to the outfall point or dechlorination feed point.
2424 2425 (B) Baffling. Baffling of the chlorine contact basin shall provide a 2426 length-to-width ratio of 5:1 or greater.
2427 2428 (viii) Controls. The minimum control for chlorination - dechlorination 2429 facilities shall include manual variation of feed rate and a portable chlorine residual monitor.
2430 2431 (b) Ozonation.
2432 2433 (i) Applied dosage rates. Ozonation system for disinfection shall provide a 2434 range of chemical feed as follows:
| 2435 | Secondary effluents | 5-15 mg/L |
|---|---|---|
| 2436 | Advanced treatment effluents | 5-10 mg/L |
| 2437 | ||
| 2438 |
2439 (ii) Piping. Injection equipment and piping in contact with ozonated air and 2440 air water emulsions shall be of stainless steel, Teflon or other material resistant to ozone. Valves 2441 carrying ozonized air shall be made of metal coated with ozone-resistant materials.
2442 2443 (iii) Mixing requirements. Ozone shall be fed to a contact tank along the 2444 length of the tank. The ozone contact tank shall be at least 15 feet (4.6 m) deep and provided with 2445 vertical serpentine baffles. Fine bubble diffusers shall be used in areas where the flow is 2446 downward.
2447 (iv) Detention time. The minimum contact time for ozone is 15 minutes at 2448 peak hourly flow. Ozone contact basins shall be covered and provided with means to collect and 2449 destroy unreacted ozone. The contact basin shall be designed to facilitate maintenance and 2450 cleaning without reducing the effectiveness of the ozonation process.
2451 2452 (c) Housing.
2453 2454 (i) Access. Where housing is specially designed for equipment, structures, 2455 rooms and areas containing chemical feed equipment used in disinfection, convenient access 2456 should be provided. Access to chemical feed rooms shall only be from the outside. Doors shall be 2457 provided with panic hardware, and open from the inside to the outside.
2458 2459 (ii) Heating and ventilation. Chemical feed rooms and chemical storage 2460 rooms shall be heated and ventilated. Ventilation shall exhaust continuously from near the floor 2461 to an outside area that will not contaminate an air inlet to any building. The exhaust shall be 2462 screened and turned downward. Continuous ventilation shall provide a complete air change six 2463 times per hour. Emergency exhaust ventilation shall provide a complete room air change 30 times 2464 per hour. The control for the emergency ventilation fan shall be on the outside of the room.
2465 2466 (iii) Visual inspection. A clear glass, gas-tight window shall be installed in an 2467 exterior door or interior wall of the disinfection chemical feed room.
2468 2469 (iv) Isolation. Chemical feed and storage rooms shall be gas-tight. 2470 Ventilation, plumbing and access shall be separated from other building parts. When ton 2471 cylinders are used for chlorine or sulfur dioxide storage, storage and feed rooms will be separate. 2472 Where powdered or granular chemicals are used, they will be stored in separate rooms from the 2473 feed room. Switches for fans and lights shall be outside the room at the entrance. Vents from 2474 feeders and storage shall discharge to the outside atmosphere above grade. Pipes and feed lines 2475 through interior walls shall be gas-tight.
2476 2477 (d) Safety.
2478 2479 (i) Leak detectors. A bottle of ammonium hydroxide shall be available for 2480 chlorine leak detection. For plants that store 1,000 lbs (454 kg) or more of chlorine, continuously 2481 monitoring leak detectors shall be provided that sound an alarm in the event of an escape of gas.
2482 2483 (ii) Repair kits. Repair kits approved by the Chlorine Institute shall be 2484 provided for plants using ton containers or tank cars.
2485 2486 (iii) Personnel equipment. Protective clothing, rubber gloves, and U.S. 2487 Bureau of Mines approved industrial canister gas masks shall be provided for each operator who
2488 will handle or prepare chemical solutions/mixtures. A respiratory protection program shall be 2489 available for all employees.
2490 2491 (iv) Emergency breathing apparatus. Industrial size canister gas masks of the 2492 type designed for chlorine gas and approved by U.S. Bureau of Mines shall be available at all 2493 installations where chlorine gas is handled. Pressure-demand, self- contained breathing apparatus 2494 shall be provided for repairing leaks to chlorine systems. A respiratory protection program shall 2495 be available for all employees.
2496 2497 (v) Instruction manuals. Instruction manuals for all elements of the 2498 disinfectant storage, preparation and application system shall be provided. These instruction 2499 manuals shall describe each component of the system, and provide a complete discussion of the 2500 operation and maintenance requirements.
2501 2502 Section 22. Effluent Structures.
2503 2504 (a) Location. The location of the effluent discharge shall be at least three miles from 2505 public water supply intakes.
2506 2507 (b) Protection from hazards. The outfall sewer shall be constructed and protected 2508 against the effects of floodwater, ice, debris, or other hazards as to insure its structural stability 2509 and freedom from stoppage. A manhole should be provided at the shore- end of all gravity sewers 2510 extending into the receiving waters.
2511 2512 Section 23. Laboratory requirements.
2513 2514 (a) Test procedures. Test procedures for analysis of monitoring samples shall 2515 conform to regulations published pursuant to Section 304(g) of the Federal Water Pollution 2516 Control Act (33 U.S.C. 466 et. seq.).
2517 2518 (b) Testing requirements. All treatment plants shall have capability to perform or 2519 contract for the self-monitoring analytical work required by discharge permits or ground water 2520 monitoring requirements. All plants shall in addition be capable of performing or contract out the 2521 analytical work required to assure good management and control of plant operation and 2522 performance. Plants operating under requirements of an industrial pretreatment program must 2523 have the capability of performing or must contract out the necessary testing to maintain the 2524 program as approved by the reviewing agency.
2525 2526 (c) Minimum requirements.
2527 2528 (i) Location and space. The laboratory shall be located away from vibrating 2529 machinery or equipment which might have adverse effects on the performance of laboratory 2530 instruments or the analyst and shall be designed to prevent adverse effects from vibration.
2531 2532 A minimum of 400 square feet (37.2 m²) of floor space shall be provided for the 2533 laboratory where an analysis program for a fulltime laboratory chemist is proposed. If more than 2534 two persons will be working in the laboratory, 100 square feet (9.3 m²) of additional space shall 2535 be provided for each additional person.
2536
2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585
(ii) Materials.
(A) Walls. Provide a durable, impervious surface that is easily cleaned.
(B) Doors. Two exit doors or openings shall be located to permit a straight egress from the laboratory; one exit shall be directly to outside of the building. Panic hardware shall be used. Interior doors shall have glass windows.
(C) Cabinets and bench tops. Cabinet and storage space shall be provided for dust-free storage of instruments and glassware.
Bench top height shall be 36 inches (0.91 m). Tops should be field joined into a continuous surface with acid, alkali, and solvent-resistant cements.
(D) Hoods. Fume hoods shall be provided where reflux or heating of toxic or hazardous materials is required.
(I) Fume hoods.
(1.) Location. A hood shall not be situated near a doorway, unless a secondary means of egress is provided.
(2.) Fixtures. All switches, electrical outlets, and utility and baffle adjustment handles shall be located outside the hood. Light fixtures shall be explosion proof.
(3.) Exhaust. Twenty-four hour continuous exhaust capability shall be provided. Exhaust fans shall be explosion proof.
(v) Sinks. The laboratory shall have a minimum of two sinks per 400 ft (37.2 m) (not including cup sinks). Sinks shall be double-well with drainboards and shall be made of epoxy resin or plastic. All water fixtures shall be provided with reduced pressure zone backflow preventers. Traps constructed of glass, plastic, or lead and accessibility for cleaning shall be provided.
(vi) Ventilation and lighting. Laboratories shall be separately air conditioned, with external air supply for 100 percent makeup volume. Separate exhaust ventilation shall be provided. Ventilation outlet locations shall be remote from ventilation inlets. Lighting shall provide 100 foot-candles at the bench top.
(vii) Gas and vacuum. If gas is required in the laboratory, natural gas shall be supplied. Digester gas shall not be used.
(viii) Water still. Distilled water shall conform to the Standard Methods for the Examination of Water and Wastewater, 15th Edition.
(ix) Emergency shower and eye wash. All laboratories shall be equipped with an emergency eye wash and shower.
2586 2587 (d) Portable testing equipment. Portable testing equipment shall be provided where 2588 necessary for operational control testing or industrial waste testing. Portable testing may be used 2589 for testing as necessary, provided the testing procedure meets the requirements of Section 304(g) 2590 of the Federal Water Pollution Control Act, if the results are to be used for permit reporting. Non- 2591 EPA certified procedures may be used for operational control or gross data generation.
2592 2593 Section 24. Operation and Maintenance Manuals.
2594 2595 (a) Where required. Plant operation and maintenance manuals are required for each 2596 new or modified treatment or pumping facility. The manuals shall provide the following 2597 information as a minimum:
2598 2599 (i) Introduction.
2600 2601 (ii) Description of facilities and unit processes through the plant from 2602 influent structures through effluent structures.
2603 2604 (iii) Plant control system.
2605 2606 (iv) Utilities and systems.
2607 2608 (v) Emergency operation and response.
2609 2610 (vi) Permit requirements and other regulatory requirements.
2611 2612 (vii) Staffing needs.
2613 2614 (viii) Index to manufacturer's manuals.
2615 2616 (b) When required. Draft operation and maintenance manuals shall be submitted to 2617 the Department of Environmental Quality at 50 percent completion of construction. Approval of 2618 the final operation and maintenance manuals is required prior to plant startup.
2619 2620 (c) Description and facilities. The description of facilities and unit processes shall 2621 include the size, capacity, model number (where applicable) and intended loading rate.
2622 2623 (i) Each unit. The manual shall describe each unit, including the function, 2624 the controls, the lubrication and maintenance schedule, as well as the following:
2625 2626 (A) Startup operations.
2627 2628 (B) Routine operations.
2629 2630 (C) Abnormal operations.
2631 2632 (D) Emergency or power outage operations.
2633 2634 (E) Bypass procedures.
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(F) Safety.
(ii) Flow diagrams. The manual shall provide flow diagrams of the entire process, as well as individual unit processes. The flow diagrams shall show the flow options under the various operational conditions listed above.
(d) Operating parameters. The O&M manual shall provide the design criteria for each unit process. The data shall include the number, type, capacity, sizes, etc., and other information, as applicable.
(e) Troubleshooting guide. Each equipment maintenance manual shall include a section on troubleshooting. These manuals are to be indexed in the plant O&M manual. The troubleshooting guide shall include a telephone number for factory troubleshooting assistance.
(f) Emergency procedures. The plant O&M manual shall detail emergency operations procedures for possible foreseeable emergencies, including power outage, equipment failure, development of unsafe conditions, oil and hazardous substances discharge into the plant, and other emergency conditions. The details shall include valve positions, flow control settings, and other information to insure continued operation of the facility at maximum possible efficiency.
The manual shall also detail emergency notification procedures to be followed to protect health and safety under various emergency conditions.
(g) Safety. The manual shall provide general information of safety in and around the plant and its components. Each unit process discussion shall include applicable safety procedures and precautions. For unit processes or operations having extreme hazards (i.e., chlorine, closed tanks, etc.) the discussion shall detail appropriate protection, rescue procedures, and necessary safety equipment.
(h) Compliance submittals. The O&M manual shall summarize the monitoring and the reporting requirements of the discharge permit. These requirements will be modified from time-to-time, and should, therefore, be placed in an appendix to the O&M manual.
(i) Maintenance manuals. Maintenance manuals shall be required for each piece of equipment. These manuals must meet the requirements of the engineer and contractor for installation and startup of equipment. The information included in the manufacturers' manuals shall not be included in the O&M manual.
(i) General content of manuals.
(A) Neatly typewritten table of contents for each volume, arranged in a systematic order.
(B) Product data.
(C) Drawings.
2684 (D) Written text as required to supplement product data for the 2685 particular installation. 2686 2687 (E) Copy of each warranty, bond and service contract issued. 2688 2689 (ii) Manuals for equipment and systems. 2690 2691 (A) Description of unit and component parts. 2692 2693 (B) Operating procedures. 2694 2695 (C) Maintenance procedures and schedules. 2696 2697 (D) Service and lubrication schedule. 2698 2699 (E) Sequence of control operation. 2700 2701 (F) Parts list. 2702 2703 (G) Recommended spare parts. 2704
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This part contains the minimum standards for the design and construction of commercial/industrial wastewater facilities. The applicant shall demonstrate to the administrator that any discharge or seepage from the wastewater facility will not cause a violation of the surface and/or groundwaters of the state in accordance with Chapter I, 'Quality Standards for Wyoming Surface Waters' and Chapter VIII, 'Quality Standards for Wyoming Groundwaters.' Due to the wide variety of wastes, wastewater and site conditions, the latest available scientific information shall be used to demonstrate that violations will not occur.
The discharge of commercial/industrial wastewater to a public sewerage system shall be allowed provided a letter of verification from the public sewerage system manager is submitted to the Department of Environmental Quality stating that the municipal system is capable of handling the added organic and/or hydraulic loads. The applicant shall demonstrate (1) that the wastewater will not adversely impact the treatment works and/or discharge or (2) that pretreatment of the wastewater shall be provided to eliminate the adverse impacts. The design and construction of any pretreatment device shall reduce the pollutants to the limits imposed by the public sewerage system manager.
Commercial/industrial facilities which generate waste that is entirely domestic waste shall be designed in compliance with Part B of Chapter 11 or Chapter 25. When the commercial/industrial facility generates a combined domestic and commercial/industrial waste, the facility may be designed in compliance with Chapter 25 or Part B of this chapter provided the applicant can demonstrate that the commercial/industrial waste will not interfere or adversely impact the treatment works or the discharge.
This section includes the standards for ponds that accept commercial/industrial waste and wastewater that is primarily organic and utilizes biological organisms for treatment and do not meet the requirements of Section 27. The presence of toxic wastes, hazardous substances, and/or petroleum products shall not interfere or adversely impact the treatment process or disposal system.
(a) Location.
(i) Extraneous surface water and groundwater shall be excluded from entering the wastewater pond or entering the wastewater flow into the pond.
(ii) Ponds shall not be located within the ordinary high water mark of perennial rivers, streams, or creeks; nor in the bottoms of rivers, streams, creeks, draws, coulees, or other natural drainages into which natural runoff may flow and/or enter.
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(iii) Ponds shall be protected from structural damage during the 100-year flood event.
(b) Basis of design.
(i) Aerobic, facultative, and anaerobic ponds shall be designed based on the type, strength characteristics, and anticipated flow rates of the wastewater. Loading rates shall be determined on a case-by-case basis using the best available technology, reference, and/or pilot studies. The affect of any toxic wastes, hazardous substances, and/or petroleum products on the wastewater treatment works and disposal system shall be evaluated. All anaerobic ponds shall be followed by an aerobic process if the system discharges to surface waters of the state.
When seepage is considered part of the design, the potential effect of groundwater mounding on the seepage rate shall be evaluated.
(ii) In addition to the above, all nonsurface water discharging ponds shall be designed on the basis of a water balance that considers net evaporation and seepage. They shall be designed to provide sufficient storage for retention of all wastewater and rainfall during the wettest occurring year of a ten-year period. Seepage shall be controlled to maintain a minimum water depth of two feet in the primary cell during the driest occurring year of a ten-year period.
(c) Pond layout.
(i) Discharging treatment systems and ponds that require liners to protect groundwater shall consist of a minimum of two cells. The largest cell shall not contain more than 55 percent of the total waste volume at the design capacity.
(ii) Inlet structures shall be submerged and located to properly distribute the wastewater flow throughout the pond(s) and shall prevent short circuiting. Influent wastewater shall not erode or disturb the liner, seal, or dike. Submerged multiple inlets are recommended. The pipe shall discharge at least ten feet from the toe of the slope.
(iii) Outlet structures from discharging treatment systems shall be capable of multilevel drawoff and have an overflow device. Outlet structures shall prevent short circuiting, prevent floating debris from discharging, and keep outlet velocities at a minimum so as not to erode or disturb the receiving channel. Erosion control material shall be designed based on flow velocities and quantities. Ice formation shall neither stop the overflow nor damage the outlet structure.
(iv) All pipe protruding through a dike or embankment shall have adequate seepage controls. Capabilities shall exist to drain the ponds for maintenance purposes. By-pass piping for each individual pond cell shall be provided.
(v) A manhole or vented cleanout wye shall be installed prior to the entrance of the influent pipe into the primary pond(s) and shall be located as close to the dike as topography permits. The influent pipe invert should be at least six inches above the maximum operating level of the pond.
2803 (vi) The maximum water depth shall be six feet in the primary cell(s) of non- 2804 aerated aerobic or facultative systems. The maximum water depth shall be 15 feet in aerated cells. 2805 The maximum water depth for subsequent cells or other types of ponds shall be determined on a 2806 case-by-case basis. 2807
2808 The minimum water depth shall be three feet in the primary cell(s) and two feet in 2809 subsequent cell(s). Cells designed for high-rate infiltration may be allowed to be dry periodically 2810 provided that the applicant can demonstrate that vegetation will be controlled and a regular 2811 maintenance program is provided. 2812
2813 (vii) Free board shall be provided to protect embankments and dikes from 2814 overtopping from wave action, and shall be a minimum of three feet above the high water level. 2815 For ponds less than two acres, two feet of freeboard may be acceptable. 2816
2817 (d) Pond construction. 2818
2819 (i) Soils used in constructing the pond bottom and dike cores (not including 2820 the liner) shall be relatively incompressible, have a low permeability, and be free from organic 2821 material or trash. The soil shall be compacted at a water content that will insure structural 2822 stability, minimize hydraulic seepage, and minimize settling. The soil shall provide an adequate 2823 foundation for the liner, if used. 2824
2825 (ii) On ponds that are not specified to receive an artificial liner, no rocks 2826 larger than six inches in length shall be permitted in any of the designated embankment. 2827
2828 On ponds that are specified to be lined with an artificial liner, rocks larger than six inches 2829 in length shall not be placed within five feet of the interior slope of any pond embankment. 2830 Material containing by volume less than 25 percent of rock larger than six inches and less than 12 2831 inches in length may be placed in the remainder of the embankment. 2832
2833 (iii) Outer dike slopes shall not be steeper than one vertical to two horizontal. 2834 Flatter slopes may be required to maintain slope stability. Outer dike slopes shall prevent surface 2835 runoff from entering the ponds. 2836
2837 Inner dike slopes shall be sloped between one vertical to four horizontal and one vertical 2838 to three horizontal. Flatter inner slopes may be allowed where vegetation due to the shallower 2839 slopes will not interfere with treatment or the dike's integrity. Interior slopes surfaced with 2840 concrete paving or riprap may be constructed at slopes of one vertical to two horizontal. 2841
2842 (iv) The minimum top dike width shall be eight feet to permit access of 2843 maintenance vehicles. Top dikes wider than eight feet shall be required when necessary to assure 2844 structural stability. 2845
2846 (v) The pond bottom shall be sufficiently flat to insure a minimum water 2847 depth as required in Section 28 (c)(vi). 2848
2849 (e) Dike protection. 2850
2851 (i) Interior embankments shall be protected from wave action with riprap, 2852 paving, or other erosion resistant material. The following conditions may be exempted from the 2853 riprap requirements:
2854 2855 (A) Ponds of one surface acre or less;
2856 2857 (B) Ponds with an artificial liner;
2858 2859 (C) Embankments cut into natural slopes when a soil liner is not 2860 provided; or
2861 2862 (D) Ponds which are sheltered from wind or where winds are slow 2863 enough that significant erosion will not occur.
2864 2865 (ii) Exterior of dikes, top of dikes, and all interior dike surfaces where riprap 2866 or a seal is not provided shall be covered with topsoil and seeded with suitable dryland grasses to 2867 prevent erosion. A uniform coarse graded gravel may be substituted for the vegetation 2868 requirement.
2869 2870 (f) Liners.
2871 2872 (i) Seepage limits. The seepage through the pond bottom and side walls 2873 shall not cause a violation of the groundwater standards as described in Chapter VIII (Quality 2874 Standards for Wyoming Groundwaters) of the Wyoming Department of Environmental Quality, 2875 Water Quality Rules and Regulations. Liners shall be required if the wastewater characteristics or 2876 site conditions will not insure the protection of the groundwater for which it is classified.
2877 2878 If the applicant cannot document that the facility poses no threat to groundwater and 2879 elects not to perform a subsurface study in accordance with Chapter III, Section 15(a) and (b), 2880 then the groundwater shall be protected from contamination by the wastewater with a liner 2881 equivalent to three feet of soil having a permeability of 10-7 cm/sec or less. When an applicant 2882 performs a subsurface study, the requirement for the liner shall be determined based on the results 2883 of the study and the groundwater protection required. In no instance shall the maximum seepage 2884 rate exceed 1/8 inch per day in the primary pond(s).
2885 2886 (ii) Soil and bentonite liners. The specifications for a soil or bentonite liner 2887 shall be based upon the results of a preliminary testing program and shall contain at a minimum 2888 the type of material, optimum and acceptable range in water content, acceptable range for 2889 compaction, and maximum allowable particle size.
2890 2891 Soil or bentonite liners used to protect groundwater quality shall meet the following 2892 criteria: Written certification that the soil liner was constructed in accordance with specifications 2893 shall be provided by a Wyoming registered professional engineer or an independent soils 2894 laboratory. Tests for water content and density shall be taken during application of each lift. 2895 Additionally, either permeability testing of undisturbed core samples from the in-place seal, or 2896 detailed tests such as particle size distribution and Atterburg limits confirming that the soil used 2897 in the liner construction was the same soil initially tested, shall be provided. In all cases, at least 2898 one test shall be provided per acre per lift, except for core sampling of the in-place liner, where 2899 one core of the completed liner shall be tested per acre.
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(iii) Synthetic liners. The thickness requirements for synthetic liners shall be determined on a case-by-case basis but shall not be less than 30 mil. The type of liner shall be compatible with the wastewater characteristics. The synthetic liner shall have a permeability equivalent to that required in Section 28(f)(i).
Synthetic liners shall be anchored to prevent movement, slippage, and flotation. The synthetic liner shall be protected from degradation by ultraviolet light, ice damage and settling of underdrain trenches. An air venting system may be required beneath the synthetic liner to expel gases trapped during installation, produced by decomposing organic material, or produced by a fluctuating water table.
(iv) Uniformity. The pond bottom shall be smooth with a maximum tolerance of ± 6 inches.
(v) Prefilling. All ponds shall be prefilled to the two foot level to protect the liner, to prevent weed growth, to encourage rapid startup of the biological process and discourage odor, to reduce freeze up problems for late fall startups, to confirm the seal’s integrity and to maintain the water of the seal at or above optimum conditions. The raw wastewater shall not be used for prefilling purposes except for anaerobic ponds.
(vi) Exfiltration evaluation. All ponds designated with a maximum exfiltration rate shall be tested for exfiltration. A maximum exfiltration rate not in excess of the design rate shall be deemed acceptable. If the exfiltration rate is deemed excessive, the seal shall be repaired and the test procedure repeated. This procedure shall be repeated until the maximum exfiltration rate criteria is met. Results of all testing shall be submitted to DEQ.
(g) Miscellaneous. A permanent flow measuring device shall be installed at the outfall of discharging pond sites and shall measure the effluent under all climatic conditions. The accuracy of the flow measuring device must be within ten percent of the actual flow. Ponds with a maximum daily discharge of less than 50,000 gallons per day may be exempted from installing a permanent flow measuring device.
This section includes the standards for wastewater retention systems for feedlot runoff. The basic concept of retention systems is to intercept and collect runoff and wastes from the animal feeding area until it can be disposed of via land application. Although retention systems are usually the most economical method of treatment, other systems will be evaluated on a case-by-case basis.
(a) Location.
(i) Groundwater shall be excluded from entering the wastewater pond or the wastewater flow into the pond.
(ii) Ponds shall not be located within the ordinary highwater mark of perennial rivers, streams, or creeks. Ponds not containing hazardous or toxic wastes may be located within the ordinary high water mark of intermittent rivers, streams, creeks, draws,
2949 coulees, or other natural drainages provided a by-pass ditch is installed capable of passing the 24 2950 hour - 100 year precipitation event.
2951 2952 (iii) The wastewater retention system shall be as near to the animal feeding 2953 operation as possible to keep construction to a minimum. The retention ponds shall be located 2954 outside the pen area for safety and maintenance purposes. Sufficient space must be left between 2955 streams or drainage areas to allow construction of the necessary collection ditches and retention 2956 ponds.
2957 2958 (b) Basis of design. All livestock confinement areas, alleyways, etc., shall be graded 2959 to prevent accumulation of surface waters and to drain all contaminated water to the retention 2960 system. Collection ditches shall be provided when necessary to intercept contaminated water. The 2961 wastewater retention system shall be designed to contain the 25 year, 24 hour precipitation event. 2962 Wastewater in the retention pond shall be removed and disposed of as soon as possible after a 2963 precipitation event. The applicant shall demonstrate that equipment is available for removing the 2964 wastewater.
2965 2966 (i) Diversion ditches. The animal feeding area shall be protected with 2967 diversion ditches that will direct uncontaminated runoff from areas above and adjacent to the site 2968 away from the ponds and shall be capable of diverting the 25-year, 24 hour precipitation event.
2969 2970 (ii) Collection ditches. Collection ditches shall be constructed around the 2971 feeding area to intercept the contaminated runoff and transport it to the settling and/or retention 2972 pond. The depth shall be adequate to handle the design flow and shall have a bottom slope 2973 sufficient to produce a velocity of not less than two feet per second. Side slopes shall not be 2974 steeper than eight horizontal to one vertical.
2975 2976 (iii) Settling pond. A settling pond ahead of the retention pond is 2977 recommended to accumulate the solids in the waste flow and to simplify their removal and final 2978 disposal. The surface area shall be sized to reduce the flow velocity below one foot per second to 2979 allow settling of solids. The pond shall be between three to six feet deep to allow sufficient 2980 capacity for holding the solids and yet allow easy removal of the solids. The outlet structure shall 2981 minimize the overflow of solids into the retention pond.
2982 2983 (iv) Retention pond. The retention pond shall be capable of containing all 2984 runoff from the feeding area for the design storm until the contaminated runoff can be disposed. 2985 If a settling pond is not provided before the retention pond, the design volume shall be increased 2986 by 10 percent to accommodate collection of solids.
2987 2988 (c) Retention pond layout.
2989 2990 (i) The shape and depth shall facilitate ease of cleaning and maintenance. A 2991 minimum freeboard of 1.5 feet shall be required above the high water level of the spillway.
2992 2993 (ii) Spillways shall be provided on all retention ponds to pass flows in excess 2994 of the 25 year, 24 hour precipitation event. The spillway shall be placed above the design high 2995 water level.
2997 (d) Retention pond construction. The retention pond construction shall meet the 2998 following requirements:
2999 3000 (i) Soils used in constructing the pond bottom and dike cores (not including 3001 the liner) shall be relatively incompressible, have a low permeability, and be free from organic 3002 material or trash. The soil shall be compacted at a water content that will insure structural 3003 stability, minimize hydraulic seepage, and minimize settling. The soil shall provide an adequate 3004 foundation for the liner, if used.
3005 3006 (ii) On ponds that are not specified to receive an artificial liner, no rocks 3007 larger than six inches in length shall be permitted in any of the designated embankments.
3008 3009 On ponds that are specified to be lined with an artificial liner, rocks larger than six inches 3010 in length shall not be placed within five feet surface of the interior slope of any pond 3011 embankment. Material containing by volume less than 25 percent of rock larger than six inches 3012 and less than 12 inches in length may be placed in the remainder of the embankment.
3013 3014 (iii) Outer dike slopes shall not be steeper than one vertical to two horizontal. 3015 Flatter slopes may be required to maintain slope stability.
3016 3017 Inner dike slopes shall be sloped between one vertical to four horizontal and one vertical 3018 to three horizontal. Flatter inner slopes may be allowed where vegetation due to the shallower 3019 slopes will not interfere with treatment or the dike's integrity. Interior slopes surfaced with 3020 concrete paving or riprap may be constructed at slopes of one vertical to two horizontal.
3021 3022 (iv) The minimum top dike width shall be eight feet to permit access of 3023 maintenance vehicles. Top dikes wider than eight feet shall be required when necessary to assure 3024 structural stability.
3025 3026 (v) The pond bottom may be sloped to facilitate pumping but shall not 3027 exceed a 0.5 percent slope.
3028 3029 (e) Liners.
3030 3031 (i) Seepage limits. The seepage through the pond bottom and side walls 3032 shall not cause a violation of the groundwater standards as described in Chapter VIII (Quality 3033 Standards for Wyoming Groundwaters) of the Wyoming Department of Environmental Quality, 3034 Water Quality Rules and Regulations. Liners shall be required if the wastewater characteristics or 3035 site conditions will not insure the protection of the groundwater for which it is classified.
3036 3037 If the applicant cannot document that the facility poses no threat to groundwater and 3038 elects not to perform a subsurface study in accordance with Chapter III, Section 15(a) and (b), 3039 then the groundwater shall be protected from contamination by the wastewater with a liner 3040 equivalent to three feet of soil having a permeability of 10-7 cm/sec or less. When an applicant 3041 performs a subsurface study, the requirement for the liner shall be determined based on the results 3042 of the study and the groundwater protection required. In no instance shall the maximum seepage 3043 rate exceed 1/8 inch per day in the primary pond(s).
3044
3045 (ii) Soil and bentonite liners. The specifications for a soil or bentonite liner 3046 shall be based upon the results of a preliminary testing program and shall contain at a minimum 3047 the type of material, optimum and acceptable range in water content, acceptable range for 3048 compaction, and maximum allowable particle size. 3049
3050 Soil or bentonite liners used to protect groundwater quality shall meet the following 3051 criteria: Written certification that the soil liner was constructed in accordance with specifications 3052 shall be provided by a Wyoming registered professional engineer or an independent soils 3053 laboratory. Tests for water content and density shall be taken during application of each lift. 3054 Additionally, either permeability testing of undisturbed core samples from the in-place seal, or 3055 detailed tests such as particle size distribution and Atterburg limits confirming that the soil used 3056 in the liner construction was the same soil initially tested, shall be provided. In all cases, at least 3057 one test shall be provided per acre per lift, except for core sampling of the in-place liner, where 3058 one core of the completed liner shall be tested per acre. 3059
3060 (iii) Synthetic liners. The thickness requirements for synthetic liners shall be 3061 determined on a case-by-case basis but shall not be less than 30 mils. The type of liner shall be 3062 compatible with the wastewater characteristics. The synthetic liner shall have a permeability 3063 equivalent to that of Section 29(e)(i). 3064
3065 Synthetic liners shall be anchored to prevent movement, slippage, and flotation. The 3066 synthetic liner shall be protected from degradation by ultraviolet light, ice damage and settling of 3067 underdrain trenches. An air venting system may be required beneath the synthetic liner to expel 3068 gases trapped during installation, produced by decomposing organic material, or produced by a 3069 fluctuating water table. 3070
3071 (iv) Exfiltration evaluation. All ponds designated with a maximum 3072 exfiltration rate shall be tested for exfiltration. A maximum exfiltration rate not in excess of the 3073 design rate shall be deemed acceptable. If the exfiltration rate is deemed excessive, the seal shall 3074 be repaired, and the test procedure repeated. This procedure shall be repeated until the maximum 3075 exfiltration rate criteria is met. Results of all testing shall be submitted to the Department of 3076 Environmental Quality. 3077
3079 This section includes the standards for non-biological treatment ponds or ponds that 3080 accept commercial/industrial waste or wastewater that is primarily non-biological in nature and 3081 does not utilize biological organisms for treatment. Radio logical affects considered by the 3082 Nuclear Regulatory Commission (NRC) from non-surface discharging treatment works within a 3083 NRC licensed permit boundary are exempt from this section. 3084
3085 (a) Location. 3086
3087 (i) Extraneous surface water and groundwater shall be excluded from 3088 entering the wastewater pond or entering the wastewater flow into the pond. 3089
3090 (ii) Ponds shall not be located within the ordinary high water mark of 3091 perennial rivers, streams, or creeks. Ponds not containing hazardous or toxic wastes may be 3092 located within the ordinary high water mark of intermit tent rivers, streams, creeks, draws, 3093
3094 coulees, or other natural drainages provided a by-pass ditch is installed capable of passing the 24 3095 hour - 100 year precipitation event. All other ponds shall be protected from structural damage 3096 during the 100-year flood event.
3097 3098 (b) Basis of design.
3099 3100 (i) Ponds shall be designed based on the type of wastewater, the wastewater 3101 strength characteristics, and the anticipated flow rates. Loading rates shall be determined on a 3102 case-by-case basis using the best available technology, reference, and/or pilot studies. The affect 3103 of any toxic wastes, hazardous substances, and/or petroleum products on the wastewater 3104 treatment process and disposal system shall be evaluated.
3105 3106 Where seepage is considered part of the design, the potential effect of groundwater 3107 mounding on the seepage rate must be evaluated.
3108 3109 (ii) In addition to the above, non-surface water discharging ponds shall be 3110 designed on the basis of a water balance that considers net evaporation and seepage. Non- 3111 discharging ponds shall be designed to provide sufficient storage to retain all wastewater and 3112 rainfall during the wettest occurring year of a ten year period.
3113 3114 (c) Pond layout.
3115 3116 (i) Discharging treatment systems and ponds that require liners to protect 3117 groundwater shall consist of a minimum of two cells. The largest cell shall not contain more than 3118 55 percent of the total waste volume at the design capacity.
3119 3120 (ii) Inlet and intracell structures for discharging treatment systems shall 3121 prevent short circuiting, and shall not erode or disturb the liner, seal or dike.
3122 3123 (iii) Outlet structures from a discharging treatment system shall have an 3124 overflow device, prevent short circuiting, prevent floating debris from discharging, and keep 3125 outlet velocities to a minimum so as not to erode or disturb the receiving channel. Erosion control 3126 material shall be designed based on flow velocities and quantities. Ice formation shall neither stop 3127 the overflow nor damage the outlet structure.
3128 3129 (iv) All pipe protruding through a dike or embankment shall have adequate 3130 seepage controls. Capabilities shall exist to drain the ponds for maintenance purposes.
3131 3132 (v) A manhole or vented cleanout wye shall be installed prior to the entrance 3133 of the influent pipe into the primary pond(s) and shall be located as close to the dike as 3134 topography permits. The influent pipe invert should be at least six inches above the maximum 3135 operating level of the pond.
3136 3137 (vi) The maximum and minimum water depth shall be determined on a case- 3138 by-case basis. However, the design engineer must demonstrate that ponds with less than two feet 3139 water depth will not have vegetation problems.
3141 (vii) Free board shall be provided to protect embankments and dikes from 3142 overtopping from wave action, and shall be a minimum of three feet above the high water level. 3143 For ponds less than two acres, two feet of freeboard may be acceptable.
3144 3145 (d) Pond construction.
3146 3147 (i) Soils used in constructing the pond bottom and dike cores (not including 3148 the liner) shall be relatively incompressible, have a low permeability, and be free from organic 3149 material or trash. The soil shall be compacted at a water content that will insure structural 3150 stability, minimize hydraulic seepage, and minimize settling. The soil shall provide an adequate 3151 foundation for the liner, if used.
3152 3153 (ii) On ponds that are not specified to receive an artificial liner, no rocks 3154 larger than six inches in length shall be permitted in any of the designated embankment.
3155 3156 On ponds that are specified to be lined with an artificial liner, rocks larger than six inches 3157 in length shall not be placed within five feet of the interior slope surface of any pond 3158 embankment. Material containing by volume less than 25 percent of rock larger than six inches 3159 and less than 12 inches in length may be placed in the remainder of the embankment.
3160 3161 (iii) Outer dike slopes shall not be steeper than one vertical to two horizontal. 3162 Flatter slopes may be required to maintain slope stability. Outer dike slopes shall prevent surface 3163 runoff from entering the ponds.
3164 3165 Inner dike slopes shall be sloped between one vertical to four horizontal and one vertical 3166 to three horizontal. Flatter inner slopes may be allowed where vegetation due to the shallower 3167 slopes will not interfere with treatment or the dike's integrity. Interior slopes surfaced with 3168 concrete paving or riprap may be constructed at slopes of one vertical to two horizontal.
3169 3170 (iv) The minimum top dike width shall be eight feet to permit access of 3171 maintenance vehicles. Top dikes wider than eight feet shall be required when necessary to assure 3172 structural stability.
3173 3174 (e) Dike protection.
3175 3176 (i) Interior embankments shall be protected from wave action with riprap, 3177 paving, or other erosion resistant material. The following conditions may be exempted from the 3178 riprap requirements:
3179 3180 (A) Ponds of one surface acre or less:
3181 3182 (B) Ponds with an artificial liner;
3183 3184 (C) Embankments cut into natural slopes where a soil liner is not 3185 provided; or
3186 3187 (D) Ponds which are sheltered from wind or where winds are slow 3188 enough that significant erosion will not occur.
3189
3190 (ii) Exterior of dikes, top of dikes, and all interior dike surfaces where riprap 3191 or a seal is not provided shall be covered with topsoil and seeded with suitable dryland grasses to 3192 prevent erosion. A uniform coarse graded gravel may be substituted for the vegetation 3193 requirement.
3194 3195 (f) Liners.
3196 3197 (i) Seepage limits. The seepage through the pond bottom and side walls 3198 shall not cause, a violation of the groundwater standards as described in Chapter VIII (Quality 3199 Standards for Wyoming Groundwaters) of the Wyoming Department of Environmental Quality, 3200 Water Quality Rules and Regulations. Liners shall be required if the wastewater characteristics or 3201 site conditions will not insure the protection of the groundwater for which it is classified.
3202 3203 If the applicant cannot document that the facility poses no threat to groundwater and 3204 elects not to perform a subsurface study in accordance with Chapter III, Section 15(a) and (b), 3205 then the groundwater shall be protected from contamination by the wastewater with a liner 3206 equivalent to three feet of soil having a permeability of 10-7 cm/sec or less. When an applicant 3207 performs a subsurface study, the requirement for the liner shall be determined based on the results 3208 of the study and the groundwater protection required. In no instance shall the maximum seepage 3209 rate exceed 1/8 inch per day in the primary pond(s).
3210 3211 (ii) Soil and bentonite liners. The specifications for a soil or bentonite liner 3212 shall be based upon the results of a preliminary testing program and shall contain at a minimum 3213 the type of material, optimum and acceptable range in water content, acceptable range for 3214 compaction, and maximum allowable particle size.
3215 3216 Soil or bentonite liners used to protect groundwater quality shall meet the following 3217 criteria. Written certification that the soil liner was constructed in accordance with specifications 3218 shall be provided by a Wyoming registered professional engineer or an independent soils 3219 laboratory. Tests for water content and density shall be taken during application of each lift. 3220 Additionally, either permeability testing of undisturbed core samples from the in-place seal, or 3221 detailed tests such as particle size distribution and Atterburg limits confirming that the soil used 3222 in the liner construction was the same soil initially tested, shall be provided. In all cases, at least 3223 one test shall be provided per acre per lift, except for core sampling of the in-place liner, where 3224 one core of the completed liner shall be tested per acre.
3225 3226 (iii) Synthetic liners. The thickness requirements for synthetic liners shall be 3227 determined on a case-by-case basis but shall not be less than 30 mils. The type of liner shall be 3228 compatible with the wastewater characteristics. The synthetic liner shall have a permeability 3229 equivalent to that of Section 30(f)(i).
3230 3231 Synthetic liners shall be anchored to prevent movement, slippage, and flotation. The 3232 synthetic liner shall be protected from degradation by ultraviolet light, ice damage and settling of 3233 underdrain trenches. An air venting system may be required beneath the synthetic liner to expel 3234 gases trapped during installation, produced by decomposing organic material, or produced by a 3235 fluctuating water table.
3236 3237 (iv) Prefilling. For soil or bentonite liners, a method of maintaining the seal 3238 at or above optimum moisture conditions is required.
3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287
(v) Exfiltration evaluation. All ponds designated with a maximum exfiltration rate shall be tested for exfiltration. A maximum exfiltration rate not in excess of the design rate shall be deemed acceptable. If the exfiltration rate is deemed excessive, the seal shall be repaired and the test procedure repeated. This procedure shall be repeated until the maximum exfiltration rate criteria is met. Results of all testing shall be submitted to the Department of Environmental Quality.
(g) Miscellaneous. A permanent flow measuring device shall be installed at the outfall of discharging pond sites and shall measure the effluent under all climatic conditions. The accuracy of the flow measuring device must be within ten percent of the actual flow. Ponds with a maximum daily discharge of less than 50,000 gallons per day may be exempted from installing a permanent flow measuring device.
This section includes the standards for sedimentation control facilities. Those sedimentation control facilities that are regulated under Water Quality Rules and Regulations, Chapter X, 'Performance/Design Standards for Surface Coal Mining Runoff Control Facilities' are exempted from this section.
(a) Location. The sedimentation control facilities shall be as near to the affected lands as possible to keep construction and containment volumes to a minimum. Sedimentation control facilities shall be located off-channel when possible. Runoff from unaffected lands should be by-passed around the containment area. All affected lands must drain to a sedimentation control facility.
(b) Basis of design. Sedimentation control facilities shall control all runoff from areas which drain into the facility from a 10-year 24-hour precipitation event in addition to the estimated sediment storage volume for one year be always available. The pond shall be drained down to the permanent pool level as soon as the effluent meets the discharge parameters. The applicant shall demonstrate that equipment or outlet structures are available for draining the pond.
(c) Layout.
(i) Inlet ditches or structures shall not erode or disturb the pond bottom.
(ii) Outlet structures, if used, shall have an overflow device, prevent short-circuiting, prevent floating debris from discharging and shall not erode or disturb the dike. All pipe protruding through a dike shall have adequate seepage control. The point of discharge into a channel shall be protected against erosion and erosion control devices shall be designed based on flow velocities.
(iii) Spillways. Sedimentation control facilities that individually contain more than 2.0 acre-feet of runoff or that individually have more than 2.0 acres of surface area or that are located on-channel shall have a spillway to by-pass precipitation events in excess of the design event. Spillways shall safely pass the 25 year flood event except when the impoundment height is greater than twenty feet or capacity exceeds twenty acre-feet; in which case the spillway shall safely pass the 100-year flood event.
3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319
(iv) By-pass ditches. If by-pass ditches are provided to transport runoff from unaffected lands, they shall be designed to pass the runoff from a 25 year precipitation event.
(v) Freeboard. Freeboard shall be provided to protect embankments and dikes from overtopping from wave action and shall be a minimum of one foot above the high water level. For ponds less than two acres, one-half foot of freeboard may be acceptable.
(d) Construction.
(i) Soils used in constructing the pond bottom and dike cores shall be relatively incompressible, have a low permeability, and be free from organic material or trash. The soil shall be compacted at a water content that will insure structural stability, minimize hydraulic seepage, and minimize settling.
Rocks larger than six inches in length shall not be placed within five feet of the interior slope surface of any pond embankment. Material containing by volume less than 25 percent of rock larger than six inches and less than 12 inch in length dimension may be placed in the remainder of the embankment.
(ii) Outer dike slopes shall not be steeper than one vertical to two horizontal. Flatter slopes may be required to maintain slope stability. Inner dike slopes shall be sloped between one vertical to four horizontal and one vertical to three horizontal.
(iii) The minimum top dike width shall be sufficient to provide structural stability.
(iv) Riprap or other acceptable erosion control shall be installed on the inner dike slopes at all anticipated levels of water. Dikes cut into existing ground shall be exempted from riprap requirements. Ponds that have less than 2.0 acres of surface area shall also be exempted.
3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354
SMALL WASTEWATER SYSTEMS
Section 32. Reserved.
Section 33. Reserved.
Section 34. Reserved.
Section 35. Reserved.
Section 36. Reserved.
Section 37. Reserved.
Section 38. Reserved.
Section 39. Reserved.
Section 40. Reserved.
Section 41. Reserved.
Section 42. Reserved.
Section 43. Reserved.
Section 44. Reserved.
Section 45. Reserved.
Section 46. Reserved.
Section 47. Reserved.
3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403
OF TREATED NON-DOMESTIC WASTEWATER
This part contains the minimum standards for the design and construction of waste and wastewater land application facilities.
The permitting of biosolids facilities or the land application of biosolids is regulated by the U.S. Environmental Protection Agency (EPA) under the Code of Federal Regulations at 40 CFR Part 503. In cases where the EPA does not issue a permit under 40 CFR 503, the Wyoming Department of Environmental Quality, Water Quality Division (WDEQ/WQD) will issue a permit. The WQD will require applicants to comply with the requirements of 40 CFR § 503.12, § 503.13, and § 503.14. The permit applications and permits will be reviewed and processed according to Chapter 3 of the Water Quality Rules and Regulations.
(a) “Overland flow land application system” is a system in which treatment is accomplished by the application of wastewater to a sloping, largely impermeable site. Treatment mechanisms include filtration, sedimentation, microbial oxidation, and crop uptake. Typical application rates range from 0.0392-0.3136 yd³/yd/hr.
(b) “Primary treatment level” (as related to pathogenic organism reduction) is that level of fecal coliform reduction (a minimum of 25 percent reduction) achievable by primary sedimentation in single cell discharging lagoons operated within the limits described in Part B, Section 13(c).
(c) “Biosolids” are solid, semi-solid, or liquid residue generated during the treatment of domestic sewage in a treatment works. Biosolids include, but are not limited to, domestic septage; scum or solids removed in primary, secondary, or advanced wastewater treatment processes; and a material derived from biosolids. Biosolids do not include ash generated during the firing of biosolids in a biosolids incinerator or grit and screenings generated during preliminary treatment of domestic sewage in a treatment works.
(a) The method for determining the size of a particular land site for accomplishing the treatment level necessary to comply with an NPDES permit or to maintain a groundwater aquifer within its present class shall be based on the number of acres (hectares) required to reduce the waste constituent identified as requiring the largest land area, based on soil assimilative capacity. The ratio used for this determination is expressed as:
3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452
Required Land Treatment Area = G/C
Where:
G = generation rate = the yearly amount of the controlling constituent to be applied for land treatment. G is listed in kilograms per year (kg/yr) or pounds per year (lbs/yr).
C = plant-soil assimilative capacity = the yearly amount of the controlling constituent which can be assimilated by plant uptake, soil adsorption and accumulation, transformation or degradation, and allow survival and maintenance of indigenous or crop plant species. C is listed in kilograms per hectare per year (kg/ha/yr) or pounds per acre per year (lbs/ac/yr).
Wastewater constituents or categories of constituents from which the land-limiting factor will be selected are generally grouped as:
| Organics | Nitrogen |
|---|---|
| Phosphorus | Heavy metals |
| Salts, acids and bases | Water |
| Oil and grease |
(b) Slope. Slow rate irrigation systems (generally less than 4.0 inches/wk application rate) will not be developed on slopes greater than 15 percent unless the site is terraced, gated pipe is placed on the contour, or vegetation, application rate and soil infiltration rate are such that runoff and erosion would not result.
Overland flow systems will not be developed on sites having less than two percent or greater than eight percent slope.
(c) Soil profile. The minimum depth of unsaturated soil strata on which a land treatment system may be developed is five feet for a slow rate system and ten feet for a rapid infiltration system, unless underdrains or pumped recovery wells are employed for lowering the water table. The applicant should refer to Part A, Section 5 for innovative technology permit requirements.
(d) Runoff and erosion. All land treatment sites will be protected from upslope runoff by diversion ditches capable of intercepting the overland flow from a 10-year 24-hour storm event, unless it is otherwise demonstrated that a storm of this size will not have an impact on the site. A runoff collection ditch is required at the base of overland flow slopes or on sloping irrigation sites where site conditions are such that over application of wastewater and/or seasonal precipitation events may threaten to pollute surface waters of the state. Provisions for storage, return and reapplication are required where a runoff collection ditch is required.
3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486
Pretreatment of wastewater shall provide sufficient organic and inorganic solids reduction, maintaining the estimated infiltration rate of the soil surface.
(a) The surface infiltration rate and hydraulic conductivity of the soil profile shall be approximated by the appropriate tests and used in determining an average annual application rate.
(b) Indigenous or crop plant species shall be capable of survival and maintenance under the conditions of increased soil moisture, salinity, and alkalinity, the classes of which will be determined by use of Figure 1, Tables 1-3 and a soil textural analysis. Waste and wastewater analyses required for this evaluation include electrical conductivity (EC in umhos/cm @ 25°C), sodium (Na+), calcium (Ca2+), magnesium (Mg2+), bicarbonate (HCO3), chloride (Cl-), sulfate (SO42-), Boron (B) and Selenium (Se), and calculation of the Sodium Adsorption Ratio (SAR) by use of the formula:
$$SAR = \frac{Na^+}{\sqrt{\frac{(Ca2+) + Mg2+)}{2}}}$$
(c) Numerical water quality criteria for special situations.
(i) For continuous and unrestricted irrigation of direct human consumption food crops or of parks, playgrounds, highway rest areas and rights-of-way (R.O.W.s), or domestic, commercial and industrial grounds with treated municipal wastewater effluent, the following quality criteria shall not be exceeded:
| pH | 4.5 - 9.0 s.u. |
|---|---|
| BOD | 10.0 mg/L Daytime |
| BOD | 30 mg/L Dusk-Dawn |
| TSS | 5.0 mg/L Daytime |
| TSS | 100 mg/L Dusk-Dawn |
| Fecal Coliforms | 200/100 mL (positive disinfection) |
| TDS | 480.0 mg/L |
| Electrical Conductivity, (EC) | 750 micromhos/cm@25°C |
| Sodium Adsorption Ratio (SAR) | 10 |
| Chlorides (Cl-) | 213 mg/L |
| Sulfates (SO42-) | 192 mg/L |
|---|---|
| Bicarbonates (HO3-) | Not greater than 50 percent of the total anion concentration in meq/L |
| Aluminum (Al) | 5.0 mg/L |
| Arsenic (As) | 1.0 mg/L |
| Beryllium (Be) | 0.1 mg/L |
| Boron (B) | 0.6 mg/L |
| Cadmium (Cd) | 0.01 mg/L |
| Cobalt (Co) | 0.5 mg/L |
| Chromium (Cr) | 0.1 mg/L |
| Copper (Cu) | 0.2 mg/L |
| Iron (Fe) | 5.0 mg/L |
| Lead (Pb) | 5.0 mg/L |
| Lithium (Li) | 0.1 mg/L |
| Manganese (Mn) | 10.0 mg/L |
| Nickel (Ni) | 0.2 mg/L |
| Selenium (Se) | 0.1 mg/L |
| Vanadium (V) | 0.1 mg/L |
| Zinc (Zn) | 2.0 mg/L |
3487 3488 3489 3490 3491
(ii) For disposal of limited volumes of industrial wastewater and sludge of less than 10 percent solids, the following criteria shall not be exceeded:
| pH | 4.5 - 9.0 s.u. |
|---|---|
| Electrical Conductivity (EC) | 3,250 micromhos/cm @25°C |
| Total Dissolved Solids | 2,100 mg/L |
| Sodium Adsorption Ratio (SAR) | 26 |
| Potassium | In combination with sodium, will not produce an SAR greater than 26 |
| Chlorides (Cl-) | 1,500 mg/L |
| Sulfates (SO42-) | 960 mg/L |
| Bicarbonates (HCO3-) | Not greater than 50 percent of the total anion concentration, meq/L |
| Arsenic (as H3AsO4, Arsenious Acid) | 0.1 mg/L |
| Boron (as H3BO3, Boric Acid) | 2.0 mg/L |
| Chromium (Cr) | 1.0 mg/L |
| Copper (Cu) | 1.0 mg/L |
| Nickel (Ni) | 0.2 mg/L |
| Selenium (Se) | 0.2 mg/L |
| Zinc (Zn) | 2.0 mg/L |
Oil and grease
20,000 lbs/ac when soil incorporated (surface 6 inches) 2,000 lbs/ac when surface applied
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
(iii) All other continuous disposal land application systems will be approved on a site specific, case by case basis by use of the applicable standards and guidelines.
(a) Surface water protection. Discharge from a land treatment system to a surface water body will be regulated by the NPDES permit process.
(b) Groundwater protection. Percolation water from land treatment of waste or wastewater shall not degrade groundwater quality to the point at which it is no longer suitable for its current or potential use as described in Chapter VIII of the Wyoming Water Quality Regulations.
Figure I - Diagram for the classification of irrigation waters
3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549
Class C1, low salinity: --
Good water with little or no likelihood of salt accumulation under the leaching provided by average irrigation practices, except where subsurface drainage is inadequate.
Class C2, medium salinity: --
Can be used if a moderate amount of leaching occurs. Plants with moderate salt tolerance can be grown in most cases without special practices for salinity control.
Class C3, high salinity: --
Cannot be used on soils with restricted drainage. With adequate drainage, considerable excess water must be applied to each irrigation; irrigations must be made more frequently, and plants with a good salt tolerance should be selected.
Class C4, very high salinity: --
Not usable under ordinary conditions. On very light and permeable soils with excellent drainage, water may be usable with a large amount of excess leaching water, frequent irrigations, and very salt-tolerant crops.
Class S1, low sodium: --
Good for almost all soils and all Wyoming crops.
Class S2, medium sodium: --
Can cause alkali problems on heavy clayey soils, with low leaching, unless gypsum (or equivalent soil amendments) are present or added to the soils.
Class S3, high sodium: --
May create harmful levels of exchangeable sodium in all soils and will require special management--good drainage, high leaching, and organic matter additions. Soils containing natural gypsum may not develop alkali troubles. Chemical amendments may be necessary, but are not feasible with waters of very high salinity.
Class S4, very high sodium: --
Generally unsuited for irrigation. Special conditions of low salinity water, favorable gypsum content of soils, tolerant crops, and special management may permit use of these waters.
These water classes are based on recommendations of the United States Regional Salinity Laboratory and numerous state agricultural experiment stations.
TABLE I - Boron Class Limits
| Class | Limits -- parts per million | Description | ||
|---|---|---|---|---|
| Sensitive crops | Semi-tolerant crops | Tolerant crops | ||
| 1 | Below 0.33 | Below 0.67 | Below 1.00 | Very low. No effect on crops. |
| 2 | 0.33 to 0.67 | 0.67 to 1.33 | 1.00 to 2.00 | Low. Very slight effect on crops. |
| 3 | 0.67 to 1.00 | 1.33 to 2.00 | 2.00 to 3.00 | Moderate. Significant yield depression. |
| 4 | 1.00 to 1.25 | 2.00 to 2.50 | 3.00 to 3.75 | High. Large yield depression anticipated. |
| 5 | Over 1.25 | Over 2.50 | Over 3.75 | Very high. Non-usable. |
TABLE II - Selenium Class Limits
| Class | Limits -- parts per million | Description |
|---|---|---|
| 1 | 0.00 to 0.10 | Low. No plant toxicity anticipated. |
| 2 | 0.11 to 0.20 | Medium. Usable -- possible long-term accumulation under particular conditions and should be watched |
| 3 | 0.21 to 0.50 | High. Doubtful -- probably toxic accumulation in plants except under especially favorable conditions |
| 4 | Over 0.50 | Very High. Non-usable under any conditions. |
TABLE III.
CHLORIDE AND SULFIDE LIMITS FOR THREE CLASSES OF IRRIGATION WATERS
| Class | Chlorides | Sulfates | |||
|---|---|---|---|---|---|
| meq/L | mg/L | meq/L | mg/L | ||
| I- | Excellent to good; or suitable for most plants under most conditions | less than 2-5.5 | 71.1 - 195.5 | 4 - 10 | 192 - 480 |
| II- | Good to injurious; harmful to some under certain conditions of soil, climate and practices | 2 - 16 | 71.1 - 568.0 | 4 - 20 | 192 - 960 |
| III- | Injurious to unsatisfactory; unsuitable under most conditions | 6 - 16 | 213 - 568 | 12 - 20 | 576 - 960 |
3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599
This part contains the minimum standards for the design and construction of mobile home park and/or campground wastewater facilities and public water supply systems.
(a) If sewerage system services are to be provided by a second person, a letter of verification from the system manager stating that they are capable of handling added organic and/or hydraulic loads shall be provided by the owner/operator of the system.
(b) A mobile home park or campground sewerage system, treatment works and disposal system shall comply with Part A, B, C, and/or D of Chapter XI except as follows:
(i) Mobile home park sewerage systems, treatment works and disposal systems shall be designed on the basis of not less than 350 gallons per site per day. Camp ground sewerage systems, treatment works and disposal systems shall be designed on the basis of not less than 100 gallons per site per day for all sewered sites or 75 gallons per site per day for all unsewered sites.
(ii) Sanitary sewers shall not be smaller than six inches in diameter. They shall be installed at a slope equal to or greater than 0.6 feet per 100 feet.
(iii) Not more than two mobile homes or campground sites shall be served by a sanitary sewer service connection pipe of a least four inches in diameter, provided the main branch of the service pipe is served by a cleanout and provided it is not longer than 50 feet. It shall be installed at a minimum slope of 1/4 inch per foot. The riser portion of the service connection pipe shall be constructed of cast iron or schedule 40 plastic pipe. The riser shall be terminated at least four inches above finished grade and shall not be located closer than five feet from a potable water service riser. The service connection pipe shall connect to the sewerage system at a maximum 45 degree bend in the direction of sewage flow.
(iv) Not more than one mobile home shall be served by a sanitary sewer service riser pipe. The riser shall be located so as to minimize the length of pipe required to connect the mobile home drain. The riser pipe shall be capped or plugged when not in use.
(v) The connection of the mobile home drain to the riser pipe shall be sealed.
(vi) If sewer service is provided to sites in a campground, the sanitary sewer service connection pipe shall comply with subsections (iii) and (iv) above.
(vii) Service connection pipes for campgrounds shall be trapped below the frost line.
3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638
(a) The potable water distribution system serving any building, mobile home lot, campground site or other appurtenance within a mobile home park or campground which is connected to a public water supply shall be considered an extension or modification of the public supply.
(b) If water is to be obtained from a public water supply, a letter of verification shall be provided from the public water supply system manager stating that the required flow can be supplied at a minimum pressure of 20 pounds per square inch under all conditions of flow throughout the proposed distribution system. A normal working pressure of 35 pounds per square inch shall be maintained in the distribution system.
(c) The public water supply serving mobile home sites, buildings and other facilities within a mobile home park shall be designed, constructed or installed and protected in accordance with Chapter XII of the Water Quality Rules and Regulations, except as follows:
(i) The water supply source shall be capable of supplying the peak water demand to a mobile home park distribution system according to the following table:
| Homes | Gallons per Minute |
|---|---|
| 25 | 65 |
| 50 | 105 |
| 75 | 145 |
| 100 | 180 |
| 150 | 235 |
| 200 | 285 |
| each additional mobile home over 200 | 1 gpm |
(ii) If fire protection is provided, the flow required shall be in addition to the requirements of subsection (i) above.
(iii) Each mobile home shall be provided with a potable water service connection pipe. It shall be 3/4 inch nominal pipe size or larger. The riser portion of the pipe shall be constructed of type K copper or steel pipe from a point below the frost line to the point of connection to the mobile home piping. The riser shall terminate at least four inches above finished grade and shall be protected from damage. The service connection pipe shall be provided with a curb stop below frost penetration. A stop and waste valve with a weep hole below grade shall not be used.
(iv) The distribution system shall be of sufficient size to supply the required volume of water at a minimum pressure of 20 pounds per square inch under all conditions of demand. A working pressure of 35 pounds per square inch shall be maintained under average day demand conditions. The distribution system mains shall not be smaller than 1 1/2 inches in diameter. If fire protection is provided, the distribution system shall meet the requirements of Chapter XII of the Water Quality Rules and Regulations.
3639 (v) If the potable water is pumped to the distribution system from wells or 3640 storage facilities, the pumps shall be capable of meeting the maximum day demand with the 3641 largest pumping unit out of service.
3642 3643 (vi) Water storage facilities shall be provided when the potable water source 3644 cannot meet the peak demand.
3645 3646 (d) The public water supply serving campground sites, buildings and/or other 3647 facilities within a campground shall be designed, constructed and protected in accordance with 3648 Chapter XII of the Water Quality Rules and Regulations except as follows:
3649 3650 (i) The public water supply source shall be capable of supplying water to a 3651 campground distribution system at a rate of 0.5 gpm/site.
3652 3653 (ii) Below ground stop and waste valves with weep holes below ground shall 3654 not be permitted.
3655 3656 (iii) A minimum pressure of 20 pounds per square inch shall be maintained 3657 throughout the distribution system under all conditions of flow. A working pressure of 35 pounds 3658 per square inch shall be maintained under average day demand conditions.
3659 3660 (iv) The distribution piping shall not be smaller than one inch in diameter. 3661 Service pipes shall not be smaller than 1/2 inch in diameter.
3662 3663
3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688
Section 60. Reserved.
Section 61. Reserved.
Section 62. Reserved.
Section 63. Reserved.
Section 64. Reserved.
Section 65. Reserved.
Section 66. Reserved.
Section 67. Reserved.
Section 68. Reserved.
Section 69. Reserved.
Section 70. Reserved.
3690
3691
3692
3693
(a) These regulations establish standards that address the primary health concerns associated with the reuse of treated wastewater. The regulations establish criteria to address the risk of pathogen exposure and infectious disease risks associated with various specified uses of treated wastewater. The regulations establish standards for the following:
3697
3698
(i) The level of wastewater treatment required;
3699
3700
(ii) Treatment reliability requirements;
3701
3702
(iii) Upper limits for water quality parameters;
3703
3704
(iv) Site access restrictions; and
3705
3706
(v) Management practices.
3707
3708
(b) In addition, the standards in this part include the parameters to be monitored, frequency of monitoring, record keeping and reporting requirements when treated wastewater is reused.
3709
3710
3711
3712
(c) These regulations establish the degree of control required for wastewater reuse through site access limitations, management practices and crop restrictions that will be commensurate with the level of treatment provided, reliability of the treatment process, quality of the wastewater and the intended use. As the quality of the wastewater and the reliability of the treatment process increases, the regulatory controls are reduced to a level consistent with protecting public health and the environment.
3713
3714
3715
3716
3717
3718
3719
(d) Pathogen reduction and public health impacts related to infectious disease agents are the major concerns associated with the reuse of treated wastewater. Chemical and toxic pollutants in treated domestic sewage are generally not a concern and are not targeted for state regulation in this chapter. There are additional constituents, such as total dissolved solids, that should be considered as part of an overall irrigation management program but are not regulated by this chapter.
3720
3721
3722
3723
3724
(a) These regulations apply to any person who prepares or applies treated wastewater from domestic sewage.
3725
3726
3727
(b) These regulations are not applicable if the primary intent is to provide treatment and/or disposal of a wastewater. Treatment and disposal are regulated under appropriate sections of Chapter 11, Wyoming Water Quality Rules and Regulations.
3728
3729
(c) If the reuse of treated wastewater involves the construction of facilities for the disinfection, delivery, storage or land application, a construction permit is required in accordance with the provisions of Chapters 3 and 11, Wyoming Water Quality Rules and Regulations. Such
3730
3731
3738 a permit constitutes approval to reuse the treated wastewater. This permit is not an operational 3739 permit and does not require periodic renewal. If there are no structural facilities requiring a 3740 construction permit, the reuse of wastewater will be authorized by a land application permit 3741 issued in accordance with these regulations. The land application permit is not an operational 3742 permit and does not require periodic renewal.
3743 3744 (d) These regulations are not applicable to the discharge of a treated wastewater 3745 which is subject to a discharge permit issued pursuant to Chapter 2, Wyoming Water Quality 3746 Rules and Regulations.
3747 3748 (e) These regulations are not applicable to treated wastewater reused at reclamation 3749 sites regulated by the Land Quality Division under Article 4 of the Wyoming Environmental 3750 Quality Act.
3751 3752 (f) These regulations are not applicable to treated wastewater reused for irrigation of 3753 grass, shrubs and trees at the treatment works.
3754 3755 (g) These regulations are not applicable to the disposal of gray water.
3756 3757 (h) These regulations are not applicable to groundwater recharge projects which are 3758 regulated by the Underground Injection Control Program of the Department of Environmental 3759 Quality, Water Quality Division.
3760 3761 Section 73. Definitions Specific to Part H.
3762 3763 The following definitions supplement those definitions contained in Section 35-11-103 of 3764 the Wyoming Environmental Quality Act.
3765 3766 (a) “Agricultural land” is land on which a food crop, a feed crop, or a fiber crop is 3767 grown. This includes range land and land used as pasture.
3768 3769 (b) “Agronomic rate” is the wastewater application rate designed to: (1) provide 3770 the amount of nitrogen needed by the food crop, feed crop, fiber crop, cover crop, or vegetation 3771 grown on the land; and (2) minimize the amount of nitrogen in the treated wastewater that passes 3772 below the root zone of the crop or vegetation grown on the land to the groundwater.
3773 3774 (c) “Class A wastewater” is treated wastewater which has received advanced 3775 treatment and/or secondary treatment and a level of disinfection so that the maximum number of 3776 fecal coliform organisms is 2.2/100 mL or less.
3777 3778 (d) “Class B wastewater” is treated wastewater which has received the equivalent 3779 of secondary treatment and a level of disinfection so that the maximum fecal coliform level is 3780 greater than 2.2/100 mL but less than 200/100 mL.
3781 3782 (e) “Class C wastewater” is treated wastewater which has received the equivalent 3783 of primary treatment and a level of disinfection so that the maximum fecal coliform level is 3784 200/100 mL or greater but less than 1000/100 mL.
3785
3786 (f) “Contaminate a groundwater aquifer” means to introduce a substance that 3787 causes the maximum contaminant level for water quality parameters specified in Chapter 8, 3788 Wyoming Water Quality Rules and Regulations to be exceeded or that causes the existing 3789 concentration of pollutants in groundwater to increase when the existing concentration of the 3790 parameters in the groundwater exceeds the maximum contaminant level specified in Chapter 8, 3791 Wyoming Water Quality Rules and Regulations.
3792 3793 (g) “Direct human consumption food crops” are crops consumed directly by 3794 humans. These include, but are not limited to fruits, vegetables and grains grown for human 3795 consumption.
3796 3797 (h) “Domestic sewage” is waste and wastewater that is primarily from human or 3798 household operations that is discharged to or otherwise enters a treatment works.
3799 3800 (i) “Forest” is a tract of land thick with trees and underbrush.
3801 3802 (j) “Groundwater” is subsurface water that fills available openings in rock or soil 3803 material such that they may be considered water saturated under hydrostatic pressure.
3804 3805 (k) “Indirect human consumption crop” are crops utilized by grazing animals and 3806 are thereby one step removed from human consumption.
3807 3808 (l) “Land with a high potential for public exposure” is land that the public uses 3809 frequently and there are no restrictions or limitations on public access during irrigation periods. 3810 This includes, but is not limited to public parks, ball fields, cemeteries, plant nurseries, turf farms, 3811 golf courses and a reclamation site located in a populated area (e.g., a construction site located in 3812 a city).
3813 3814 (m) “Land with moderate potential for public exposure” is land that is accessible 3815 to the public but access is limited during irrigation periods. This would include the facilities in 3816 (n) where signing and fencing is provided to restrict access.
3817 3818 (n) “Land with a low potential for public exposure” is land that the public uses 3819 infrequently. This includes, but is not limited to agricultural land, forest, and a reclamation site 3820 located in an unpopulated area (e.g., a strip mine located in a rural area).
3821 3822 (o) “Municipal wastewater” means the discharge from a publicly owned or con- 3823 trolled treatment system receiving primarily domestic wastewater or a combination of domestic, 3824 commercial and industrial wastewater that is normally treated in a primary, secondary or 3825 advanced wastewater treatment process.
3826 3827 (p) “Pathogenic organisms” are disease-causing organisms. These include, but are 3828 not limited to certain bacteria, protozoa, viruses, and viable helminth ova.
3829 3830 (q) “Pasture” is land on which animals feed directly on feed crops such as legumes, 3831 grasses, grain stubble, or stover.
3832 3833 (r) “Permitting authority” is the Department of Environmental Quality, Water 3834 Quality Division.
3835 3836 (s) “Pollutant” is an organic substance, an inorganic substance, a combination of 3837 organic and inorganic substances, or a pathogenic organism that, after discharge and upon 3838 exposure, ingestion, inhalation, or assimilation into an organism either directly from the 3839 environment or indirectly by ingestion through the food chain, could, on the basis of information 3840 available to the permitting authority, cause death, disease, behavioral abnormalities, cancer, 3841 genetic mutations, physiological malfunctions (including malfunctions in reproduction), or 3842 physical deformations in either organisms or offspring of the organisms.
3843 3844 (t) “Pollutant limit” is a numerical value that describes the amount of a pollutant 3845 allowed per unit amount of wastewater (e.g., milligrams per liter).
3846 3847 (u) “Range land” is open land used for grazing by livestock and/or wildlife on 3848 which the natural potential plant community is dominated by grasses, grasslike plants, forbs and 3849 shrubs.
3850 3851 (v) “Reclamation site” is drastically disturbed land that is reclaimed using waste- 3852 water. This includes, but is not limited to, strip mines and construction sites.
3853 3854 (w) “Runoff” is rainwater, leachate, or other liquid that drains overland on any part 3855 of a land surface and runs off of the land surface.
3856 3857 (x) “Treated wastewater” is domestic sewage discharged from a treatment works 3858 after completion of the treatment process.
3859 3860 (y) “Treatment works” is either a publicly or privately owned device or system 3861 used to treat either domestic sewage or a combination of domestic sewage and commercial or 3862 industrial waste of a liquid nature.
3863 3864 Section 74. Compliance with Other Laws and Regulations.
3865 3866 Nothing in these regulations or the permits issued pursuant to these regulations shall be 3867 construed to relieve the recipient of a permit of the need to comply with any other law, rule or 3868 regulation. It is the duty of the permittee to comply with all applicable federal, state and local 3869 laws or regulations in the exercise of activities authorized pursuant to these regulations.
3870 3871 Specifically, the permittee is responsible for complying with the water right requirements 3872 of the Wyoming State Engineers Office.
3873 3874 Section 75. Compliance Period.
3875 3876 (a) Compliance with the standards in these regulations shall be achieved as 3877 expeditiously as practicable, but in no case later than one year after final adoption. When 3878 compliance with the standards requires construction of new or modified treatment facilities, 3879 compliance with the standards shall be achieved as expeditiously as practicable, but in no case 3880 later than two years after final adoption.
3881 3882 (b) Water reuse facilities operating under authority granted by the Department of 3883 Environmental Quality are required to notify the department of the nature and requirements of the
3884 existing authorization. Existing authorized facilities are not required to comply with the 3885 requirements of these regulations unless the administrator determines it is necessary to revise the 3886 existing authorization in order to protect public health and the environment. Existing facilities 3887 are required to comply with the monitoring and reporting requirements of Sections 83, 84, 85 and 3888 86.
3890 Section 76. Permits, Enforceability and Applications.
3891 3892 (a) The requirements in these regulations may be implemented through:
3893 3894 (i) A land application permit issued by the Department of Environmental 3895 Quality, Water Quality Division in accordance with these regulations;
3896 3897 (ii) A construction and operation permit issued by the Department of 3898 Environmental Quality, Water Quality Division in accordance with Chapters 11 and 34, Wyoming 3899 Water Quality Rules and Regulation; or
3900 3901 (iii) A general statewide operation permit issued by the Water Quality 3902 Division, Department of Environmental Quality for the Land Application of Treated Waste- 3903 water.
3904 3905 (b) No person shall prepare or use treated wastewater except in accordance with the 3906 requirements of these regulations.
3907 3908 (c) Applications for permits shall be submitted to the Department of Environmental 3909 Quality, Water Quality Division in accordance with the requirements of Chapter 3, Wyoming 3910 Water Quality Rules and Regulations. The application materials submitted shall be adequate to 3911 demonstrate compliance with all requirements of this part. It shall be the responsibility of the 3912 applicant to demonstrate that the proposed reuse of treated wastewater will not endanger public 3913 health or the environment.
3914 3915 (d) The person who prepares treated wastewater and makes it available to another 3916 person for reuse shall provide, as part of the application required by Section 76 (c), a 3917 demonstration that all of the requirements of this chapter will be met. This will include access 3918 restrictions, management practices, record keeping and reporting requirements which may be the 3919 responsibility of another person who will apply the treated wastewater. This demonstration may 3920 be in the form of either a written agreement with the applier specifying his or her responsibilities 3921 or a separate permit application from the applier. If the method selected is an agreement, the 3922 agreement must cover appropriate access restrictions, management practices, record keeping and 3923 reporting requirements of this chapter. If the method selected is a separate permit for the applier 3924 the permit application by the applier must address the same requirements.
3925 3926 (e) Any person who prepares treated wastewater outside of the state to be applied 3927 within the state must either obtain a permit to land apply in accordance with this chapter or 3928 provide the wastewater to a person who has a permit.
3929 3930 (f) Any person who prepares treated wastewater outside of the State of Wyoming 3931 that is to be applied to land within the State of Wyoming and opts not to obtain a permit shall 3932 provide written notice, prior to the initial application of treated wastewater to the reuse site by the
3933 applier, to the Department of Environmental Quality, Water Quality Division. The notification 3934 shall include the following:
3935 3936 (i) The location, by either street address or latitude and longitude, of each 3937 reuse site;
3938 3939 (ii) The approximate time period the treated wastewater will be applied to 3940 the site;
3941 3942 (iii) The name, address, telephone number, and National Pollutant Discharge 3943 Elimination System permit number (if appropriate) for the person who prepares the treated 3944 wastewater;
3945 3946 (iv) The name, address, telephone number of the person who will reuse the 3947 treated wastewater; and
3948 3949 (v) Documentation that the requirements of this regulation have been met.
3950 3951 Section 77. Exclusions.
3952 3953 (a) Treatment processes. These regulations do not establish requirements for 3954 processes used to treat wastewater.
3955 3956 (b) Selection of a reuse practice. This chapter does not require the selection of a 3957 reuse practice. The determination of the manner in which treated wastewater is to be reused is a 3958 local determination.
3959 3960 Section 78. General Management Practices.
3961 3962 (a) Treated wastewater shall be applied for the purpose of beneficial reuse and shall 3963 not exceed the irrigation need or demand of the vegetation at the site. Winter irrigation is 3964 considered to be beneficial reuse.
3965 3966 (b) Treated wastewater shall not be applied to agricultural land, forest, a public 3967 contact site, or a reclamation site at an application rate that is greater than the agronomic rate for 3968 the vegetation at the site.
3969 3970 (c) Treated wastewater shall not be applied in a manner that will contaminate a 3971 groundwater aquifer.
3972 3973 (d) Treated wastewater will be applied in a manner and time that will not cause any 3974 surface runoff to leave the application site and enter surface waters of the state.
3975 3976 (e) Direct human consumption food crops shall not be harvested for 30 days after 3977 application of treated wastewater.
3978 3979 (f) Animals shall not be allowed to graze on the land for 30 days after application of 3980 Class C treated wastewater.
3981
3982 (g) Fencing and signing shall be provided at sites where Class B treated wastewater 3983 is proposed for reuse on land with a moderate potential for public exposure.
3984 3985 (h) Signing shall be provided at sites where Class B or Class C treated wastewater is 3986 proposed for reuse on land with a low potential for public exposure in order to protect the health 3987 and safety of workers.
3988 3989 Section 79. Site Isolation Requirements.
3990 3991 No person shall reuse treated wastewater on an application site except in accordance with 3992 the restrictions specified below.
3993 3994 (a) Isolation of spray irrigation systems.
3995 3996 (i) Wind drift shall not leave the application site.
3997 3998 (ii) If Class A or Class B wastewater is reused for irrigation, a 30 foot buffer 3999 zone is required between the reuse site and adjacent property lines. Public right-of-ways may be 4000 utilized to meet this requirement for a buffer zone.
4001 4002 (iii) If Class C wastewater is reused for irrigation a 100 foot buffer zone is 4003 required between the reuse site and adjacent property lines and any public right-of-way.
4004 4005 (iv) A 30 foot separation distance is required between reuse sites and all 4006 surface waters.
4007 4008 (v) A 100 foot separation distance is required between reuse sites and all 4009 potable water supply wells.
4010 4011 (vi) Surface runoff shall not leave the application site.
4012 4013 (b) Isolation distances between reuse sites irrigated by flood irrigation systems.
4014 4015 (i) Surface runoff shall not leave the application site.
4016 4017 (ii) If Class A or Class B wastewater is reused for irrigation, a 30 foot buffer 4018 zone is required between the reuse site and adjacent property lines. Public right-of-ways may be 4019 utilized to meet this requirement for a buffer zone.
4020 4021 (iii) If Class C wastewater is reused for irrigation, a 30 foot buffer zone is 4022 required between the reuse site and adjacent property lines and any public right-of-way.
4023 4024 (iv) A 30 foot separation distance is required between reuse sites and all 4025 surface waters.
4026 4027 (v) A 100 foot separation distance is required between reuse sites and all 4028 potable water supply wells.
4029
4030 (c) Drip irrigation systems. The buffer zone requirements of Section 79(a)(ii) and 4031 79(b)(ii) for Class A and B wastewaters may be met by the use of drip irrigation systems.
4032
4033
4034
4035
Treated wastewater must receive the equivalent of primary treatment and a maximum fecal coliform value of less than 1000/100 ml in order to be reused in accordance with these regulations.
4038
4039
4040
4041
(a) The ability of the treatment process to deliver the class of treated wastewater required for a particular use will be considered by the permitting authority when approving or deny ing wastewater reuse in accordance with Section 76. The criteria for evaluating treatment reliability may include the following as appropriate:
4045
4046
(i) Multiple units and equipment;
4047
4048
(ii) Alternative power sources;
4049
4050
(iii) Alarm systems and instrumentation;
4051
4052
(iv) Operator certification and stand-by capability;
4053
4054
(v) Bypass and dewatering capability;
4055
4056
(vi) Frequency of sampling;
4057
4058
(vii) Hydraulic and organic loading design capabilities; and
4059
4060
(viii) Emergency storage.
4061
4062
(b) Where treatment reliability cannot be provided by existing facilities, the reuse may be approved based upon the preparer's ability to dispose of the treated wastewater in an acceptable alternative manner or to reuse the treated wastewater for a less restrictive authorized reuse as indicated in Section 82.
4066
4067
4068
4069
(a) Class A wastewater may be used for the following purposes:
4070
4071
(i) Irrigation of land with a high potential for public exposure;
4072
4073
(ii) Irrigation of land with a moderate potential for public exposure;
4074
4075
(iii) Irrigation of land with a low potential for public exposure;
4076
4077
(iv) Irrigation of direct human consumption food crops; and
4078
4079 (v) Irrigation of indirect human consumption food crops. 4080 4081 (b) Class B wastewater may be used for the following purposes: 4082 4083 (i) Irrigation of land with a moderate potential for public exposure; 4084 4085 (ii) Irrigation of land with a low potential for public exposure; 4086 4087 (iii) Irrigation of direct human consumption food crops; and 4088 4089 (iv) Irrigation of indirect human consumption food crops. 4090 4091 (c) Class C wastewater may be used for the following purposes: 4092 4093 (i) Irrigation of land with a low potential for public exposure; and 4094 4095 (ii) Irrigation of indirect human consumption food crops. 4096
4097 4098 4099 (a) Sampling. Representative samples of the treated wastewater that is to be reused 4100 shall be collected and analyzed by the person who prepares the wastewater. 4101 4102 (b) Methods. Waste constituents shall be analyzed in accordance with 40 CFR Part 4103 136, Guidelines Establishing Test Procedures for the Analysis of Pollutants. 4104 4105 (c) Parameters. The treated wastewater shall be analyzed for the following: 4106 4107 (i) Fecal coliform; 4108 4109 (ii) Nitrate as N; 4110 4111 (iii) Ammonia as N; 4112 4113 (iv) pH; 4114 4115 (v) Parameters identified in 40 CFR Part 122, Appendix D, Table III, when 4116 required by the NPDES permit; and 4117 4118 (vi) Other parameters identified in the permit. 4119 4120 (d) Frequency for monitoring for these pollutants shall be: 4121 4122 (i) For lagoon systems, once per month or the frequency specified in the 4123 NPDES discharge permit whichever is more frequent; 4124 4125 (ii) For mechanical plants, once per week or the monitoring frequency 4126 specified in the NPDES discharge permit whichever is more frequent; and 4127
4128 4129 4130 4131 4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173 4174 4175
(iii) For monitoring of parameters identified in Section 83 (c) (v), shall be conducted at the frequency specified in the NPDES discharge permit.
In the event that the monitoring program identified in Section 83 indicates noncompliance with the fecal coliform levels associated with the class of wastewater and the appropriate authorized reuse identified in Section 82, the responsible party shall take the following actions.
(a) Discontinue the reuse of treated wastewater immediately. The responsible party may discharge in compliance with the requirements of an NPDES permit or convert to any authorized reuse which is consistent with the quality of the treated wastewater.
(b) Report the noncompliance to the permitting authority as soon as possible, but no later than the next working day.
(c) Initiate monitoring of the parameter in noncompliance on a daily or more frequent basis in order to adequately demonstrate that the treated wastewater can reliably meet the reuse criteria.
(d) Report the results on the noncompliance monitoring to the permitting authority. Upon adequate demonstration by the responsible party that the reuse criteria can be reliably met, the permitting authority may grant verbal and written authorization to re-institute the discontinued reuse.
(e) The responsible party shall provide a written report within 15 days of the resolution of the event which will contain the following:
(a) A person who prepares treated wastewater shall develop the following information and shall retain the information for five (5) years.
(i) The concentration of each applicable pollutant listed in Section 83 (c) in the treated wastewater at the frequency specified in Section 83 (d).
4176 (ii) A description of how the minimum level of treatment requirements in 4177 Section 80 are met. 4178 4179 (iii) A description of how the treatment reliability requirements in Section 81 4180 are met. 4181 4182 (iv) The following certification statement: 'I certify, under penalty of law, 4183 that the level of treatment requirements in Section 80 of Chapter 11, Wyoming Water Quality 4184 Rules and Regulations, the treatment reliability requirements in Section 81 and the water quality 4185 parameters have been met. This determination has been made under my direction and 4186 supervision. I am aware that there are significant penalties for false certification.' 4187 4188 (b) A person who prepares treated wastewater shall obtain the following information 4189 from any person who reuses the treated wastewater and shall retain the information for five years. 4190 4191 (i) The location, by either street address or latitude and longitude, of each 4192 site on which treated wastewater is applied. 4193 4194 (ii) The number of acres on each site on which treated wastewater is applied. 4195 4196 (iii) The date and time treated wastewater is applied to each site. 4197 4198 (iv) The cumulative amount of treated wastewater applied to each site. 4199 4200 (v) The following certification statement: 'I certify, under penalty of law, 4201 that the general management practices in Section 78 of Chapter 11, Wyoming Water Quality 4202 Rules and Regulations, and the site isolation requirements in Section 79 have been met. This 4203 determination has been made under my direction and supervision. I am aware that there are 4204 significant penalties for false certification.' 4205 4206 Section 86. Reporting. 4207 4208 (a) A person preparing treated wastewater shall submit the information in Section 85 4209 (a) and (b) to the permitting authority on an annual basis. 4210 4211 (b) A person who reuses treated wastewater shall submit the information in Section 4212 85 (b) to the person who prepares the treated wastewater on an annual basis if he or she is 4213 operating under an agreement with the applier. If the application is regulated by a permit, the 4214 information shall be submitted to the permitting authority. 4215 4216 4217 Section 87. Operation and Maintenance Manual. 4218 4219 (a) Any person responsible for the application of treated wastewater shall provide an 4220 operation and maintenance manual as part of the agreement or permit application required by 4221 Section 75 (d). 4222 4223 (b) The operation and maintenance manual shall include the following: 4224
4225 (i) Description of the facilities; 4226 4227 (ii) Description of the application system; 4228 4229 (iii) Procedures for emergency operation and spill events; 4230 4231 (iv) Procedures for meeting permit and regulatory requirements; 4232 4233 (v) Maintenance and operation requirements for any mechanical equipment; 4234 and 4235 (vi) Description of how the monitoring, record keeping and reporting 4236 requirements of this chapter will be met. 4237 4238 4239 4240 4241 4242 15-0052 gjt