IDAPA 58.01.16
This rule applies to those planning, designing, constructing, and operating wastewater facilities including lagoons and other systems for the treatment of domestic or industrial wastewater prior to disposal through land application or discharge to a surface water. The Department uses standards identified within these rules to approve plans and specifications for the design and construction of wastewater treatment systems.
This rule establishes the procedures and requirements for the planning, design and operation of wastewater facilities and the discharge of wastewaters and human activities which may adversely affect public health and water quality in the waters of the state.
This rule implements the following statutes passed by the Idaho Legislature:
Health and Safety -
Mary Anne Nelson Department of Environmental Quality 1410 N. Hilton Boise, ID 83706 Phone: (208) 373-0291 Email: mary.anne.nelson@deq.idaho.gov www.deq.idaho.gov
This rule chapter will be reviewed in compliance with Section 67-5292, Idaho Code, and in accordance with the 8-year rule review schedule linked here.
000. Legal Authority. ... 4
001. Scope. ... 4
002. (Reserved) ... 4
003. Administrative Provisions. ... 4
004. Incorporation By Reference. ... 4
005. -- 006. (Reserved) ... 4
007. Use Of Guidance In Design And Review. ... 4
008. Referenced Material. ... 4
009. (Reserved) ... 5
010. Definitions. ... 5
011. -- 200. (Reserved) ... 11
201. Wastewater System Requirements. ... 11
202. Classification Of Community Wastewater Systems. ... 12
203. Community Wastewater System Operator Licensure Requirements. ... 12
204. Contracting For Services. ... 13
205. -- 259. (Reserved) ... 13
260. Subsurface Sewage Disposal. ... 13
261. -- 399. (Reserved) ... 13
400. Review Of Plans For Municipal Wastewater Systems. ... 13
401. Review Of Plans For Nonmunicipal Wastewater Systems. ... 15
402. -- 408. (Reserved) ... 16
409. Demonstration Of Technical, Financial, And Managerial Capacity. ... 16
410. Facility And Design Standards For Municipal Wastewater Systems: Facility Plans. ... 17
411. Facility And Design Standards For Municipal Wastewater Systems: Preliminary Engineering Reports. ... 19
412. -- 424. (Reserved) ... 23
425. Facility And Design Standards For Municipal Wastewater Systems: Operation And Maintenance Manuals. ... 23
426. -- 429. (Reserved) ... 23
430. Facility And Design Standards For Municipal Wastewater Systems -- Design And Construction Of Wastewater Pipelines. ... 23
431. -- 439. (Reserved) ... 27
440. Facility And Design Standards For Municipal Wastewater Systems: Wastewater Pumping Stations. ... 27
441. Facility And Design Standards For Municipal Wastewater Systems: Individual Service Connection Wastewater Pumping Stations. ... 32
442. -- 449. (Reserved) ... 34
450. Facility And Design Standards For Municipal Wastewater Systems: Wastewater Treatment Facilities: General. ... 34
451. -- 454. (Reserved) ... 38
455. Private Wastewater Treatment Plants. ... 38
456. -- 459. (Reserved) ... 40
460. Facility And Design Standards For Municipal Wastewater Systems: Screening And Grit Removal. ... 40
461. -- 469. (Reserved) ... 40
470. Facility And Design Standards For Municipal Wastewater Systems: Settling. 40
471. -- 479. (Reserved) ... 41
480. Facility And Design Standards For Municipal Wastewater Systems: Sludge Processing, Storage, And Disposal. ... 41
481. -- 489. (Reserved) ... 41
490. Facility And Design Standards For Municipal Wastewater Systems: Biological Treatment. ... 41
491. -- 492. (Reserved) ... 45
493. Facility And Design Standards For Municipal Wastewater Systems: Wastewater Lagoons. ... 45
494. -- 499. (Reserved) ... 48
500. Facility And Design Standards For Municipal Wastewater Systems: Disinfection. ... 48
501. -- 509. (Reserved) ... 51
510. Facility And Design Standards For Municipal Wastewater Systems: Supplemental Treatment Processes. ... 51
511. -- 518. (Reserved) ... 51
519. Facility And Design Standards For Municipal Wastewater Systems: Septage Transfer Stations. ... 52
520. Facility And Design Standards For Municipal Wastewater Systems: Handling And Treatment Of Septage At A Wastewater Treatment Facility. ... 53
521. -- 599. (Reserved) ... 53
600. Land Application Of Wastewaters Or Recharge Waters. ... 53
601. -- 649. (Reserved) ... 54
650. Sludge Management Program. ... 54
651. -- 659. (Reserved) ... 55
660. Waivers. ... 55
661. -- 999. (Reserved) ... 55
000. LEGAL AUTHORITY.
Chapters 1 and 36, Title 39, Idaho Code.
(7-1-26)
001. SCOPE.
These rules establish the procedures and requirements for the planning, design and operation of wastewater facilities, the disposal of wastewater, and human activities which may adversely affect public health and water quality. (7-1-26)
002. (RESERVED)
003. ADMINISTRATIVE PROVISIONS.
Persons may be entitled to appeal agency actions authorized under these rules pursuant to IDAPA 58.01.23, “Contested Case Rules and Rules for Protection and Disclosure of Records.” (3-31-22)
004. INCORPORATION BY REFERENCE.
Sections 401.2.9, 401.3.4, 401.3.6, 501.3.4, and 505.3.3 of “Idaho Standards for Public Works Construction,” 2020 Edition, are incorporated by reference into these rules. This document is available for review at the Department of Environmental Quality, 1410 N. Hilton, Boise, Idaho, (208)373-0502, or can be purchased for a fee from the Local Highway Technical Assistance Council (LHTAC) at LHTAC, 3330 Grace Street, Boise, ID, 83703, (208) 344-0565. (7-1-26)
005. – 006. (RESERVED)
007. USE OF GUIDANCE IN DESIGN AND REVIEW.
Guidance documents are used to assist both designers and reviewers in determining a reasonable way to achieve compliance with these rules. Nothing in these rules makes the use of a particular guidance or guidance document mandatory. If the plans and specifications comply with applicable facility and design standards as set out in these rules, Section 39-118, Idaho Code, requires that the Department not substitute its judgment for that of the design engineer concerning the manner of compliance. If the design engineer needs assistance as to how to comply with a particular rule, the design engineer may use the referenced guidance documents listed in Section 008 for that assistance. However, the design engineer may also use other guidance or provide documentation to substantiate their own professional judgment. (7-1-26)
008. REFERENCED MATERIAL.
01. Recommended Standards for Wastewater Facilities. A Report of the Wastewater Committee of the Great Lakes-Upper Mississippi River Board of State and Provincial Public Health and Environmental Managers. https://www.health.state.mn.us/communities/environment/water/docs/tenstates/tenstatestan2014.pdf. (7-1-26)
02. “Idaho Standards for Public Works Construction”. This document is available for review at the Department of Environmental Quality, 1410 N. Hilton, Boise, Idaho, (208)373-0502, or can be purchased for a fee through the Local Highway Technical Assistance Council (LHTAC) at LHTAC, 3330 Grace Street, Boise, ID, 83703, (208) 344-0565. (7-1-26)
03. Water Environment Federation (WEF) Manuals of Practice. Water Environment Federation, 601 Wythe Street, Alexandria, VA, 22314-1994, 1-800-666-0206, http://www.wef.org. (3-31-22)
04. American Society of Civil Engineers (ASCE) Manuals and Reports on Engineering Practices. American Society of Civil Engineers, 1801 Alexander Bell Drive, Reston, VA 20191, 800-548-2723, http://www.asce.org. (3-31-22)
05. “Design Criteria for Mechanical, Electric, and Fluid System and Component Reliability.” U.S. EPA (EPA-430-99-74-001), http://www.epa.gov. (3-31-22)
06. American National Standard Institute/Hydraulic Institute ANSI/HI 9.8, American National Standard for Centrifugal and Vertical Pump Intake Design. 1819 L Street NW Suite 600, Washington, DC 20036, (202) 293-8020, www.ansi.org. (3-31-22)
07. The Compressed Gas Association Publication CGA G-3-1995, “Sulfur Dioxide.” (3-31-22)
08. “Wastewater Engineering, Treatment and Reuse,” Metcalf and Eddy. (3-31-22)
“Ultraviolet Disinfection Guidelines for Drinking Water and Water Reuse,” National Water Research Institute/American Water Works Association (AWWA) Research Foundation, 6666 West Quincy Avenue, Denver, CO 80235, (800)926-7337, http://www.awwa.org. (3-31-22)
10. Pumping Station Design - Third Edition 2006. Garr M. Jones. Elsevier Publications. (3-31-22)
11. Idaho Waste Management Guidelines for Aquaculture Operations 1997. Aquaculture Waste Guidelines Advisory Committee. https://freshwater-aquaculture.extension.org/wp-content/uploads/2019/08/Idaho_Waste_Management_Guidelines_for_Aquaculture_Operations.pdf (7-1-26)
009. (RESERVED)
The terms “Board,” “Department,” “Director,” “Person,” and “Waters” are defined in Section 39-103, Idaho Code. The term “Ground water” (Groundwater) is defined in Section 39-121, Idaho Code. The terms “Beneficial Use” and “Watershed” are defined in IDAPA 58.01.02, “Water Quality Standards.” The term “Like-Kind Replacement” is defined in IDAPA 58.01.08, “Idaho Rules for Public Drinking Water Systems.” The terms “Recycled Water” and “Reuse” are defined in IDAPA 58.01.17, “Recycled Water Rules.” The terms “Point Source” and “Water Pollution” are defined in IDAPA 58.01.25, “Idaho Pollutant Discharge Elimination System Rules.” (7-1-26)
01. Adequate Emergency Storage Capacity. Lift station wet well emergency storage capacity is the volume of the wet well measured between the high water alarm and the gravity sewer invert into the wet well. The collection system will not be used in the calculation for emergency storage. Adequate storage is defined as twice the estimated emergency response time multiplied by the peak hour flow to the wet well where the minimum emergency response time is thirty (30) minutes, unless otherwise approved by the Department. The high water alarm must be placed at an elevation below the wet well invert sufficient to achieve the defined volumetric emergency storage capacity. (7-1-26)
02. Biochemical Oxygen Demand (BOD). The measure of the amount of oxygen necessary to satisfy the biochemical oxidation requirements of organic materials at the time the sample is collected; unless otherwise specified, this term will mean the five (5) day BOD incubated at twenty (20) degrees C. (3-31-22)
03. Blackwaste. Human body waste, such as excreta or urine. This includes toilet paper and other products used in the practice of personal hygiene. (3-31-22)
04. Blackwater. A wastewater whose principal pollutant is blackwaste; a combination of blackwaste and water. (3-31-22)
05. Buildout. The estimated future wastewater capacity needs at full development, based on land use plans, zoning, or facility planning. Design capacities must account for these conditions unless expansion is readily achievable. (7-1-26)
06. Capacity. The capabilities required of a wastewater system to achieve and maintain compliance with these rules. It is divided into three (3) elements: (7-1-26)
a. Technical capacity means: (7-1-26)
i. Physical infrastructure to safely collect wastewater and consistently meet disposal standards and treatment requirements; (7-1-26)
ii. Ability to meet the requirements of routine and emergency operations; and (7-1-26)
iii. Ability of system personnel to adequately operate and maintain the system and to otherwise implement technical knowledge. Training of operators is required, as appropriate, for the system size and complexity. (7-1-26)
b. Financial capacity means the financial resources of the wastewater system, including an
appropriate budget; rate structure; cash reserves sufficient for current operation and maintenance, future needs and emergency situations; and adequate fiscal controls. (3-31-22)
c. Managerial capacity means the management structure of the wastewater system embodies the aspects of wastewater system operations, including, but not limited to: (7-1-26)
i. Short and long range planning; (3-31-22) ii. Personnel management; (3-31-22) iii. Fiduciary responsibility; (3-31-22) iv. Emergency response; (3-31-22) v. Customer responsiveness; and (3-31-22) vi. Administrative functions such as billing and consumer awareness. (3-31-22)
07. Class A Recycled Water. For a comprehensive description of Class A recycled water, refer to IDAPA 58.01.17, "Recycled Water Rules." (7-1-26)
08. Class A Recycled Water Distribution System. The delivery system for Class A recycled water. The distribution system does not include any of the collection or treatment portions of the wastewater facility. (7-1-26)
09. Collection System. That portion of the wastewater system or treatment facility in which wastewater is received from the premises of the user and conveyed to the point of treatment through a series of lines, pipes, manholes, pumps/lift stations and other appurtenances. For the purposes of municipal wastewater, a wastewater system must serve two or more wastewater service connections. (7-1-26)
10. Compliance Schedule or Compliance Agreement Schedule. A schedule of remedial and preventative measures and sequence of actions leading to compliance with a regulation, statute or rule, enforceable as set forth in Sections 39-116 and 39-116A, Idaho Code, respectively. (3-31-22)
11. Discharge. When used without qualification, any spilling, leaking, emitting, escaping, leaching, or disposing of a pollutant into waters. (7-1-26)
12. Disinfection. A method of reducing the pathogenic or objectionable organisms by means of chemicals or other acceptable means. (3-31-22)
13. Disposal. Removal of wastewater derived from municipal and nonmunicipal sources utilizing discharge, reuse, total containment, or other allowable methods. (7-1-26)
14. Disposal Facility. Any facility used for disposal of any wastewater. Facilities for the disposal of sludge are regulated under Section 650 of these rules. (3-31-22)
15. Effluent. Any treated wastewater disposed from a treatment facility. (7-1-26)
16. Equivalent Dwelling Unit (EDU). A measure where one (1) unit is equivalent to wastewater generated from one (1) single-family detached housing unit. For example, a business generating three (3) times as much wastewater as an average single-family detached housing unit would be considered three (3) equivalent dwelling units. (3-31-22)
17. Facility Plan. Comprehensive planning document for a municipal wastewater system describing the overall existing system - including the collection, treatment and disposal systems - and the plan for future systems including upgrades and additions. A Facility Plan may be referred to as a master plan or facilities planning study and is updated on a regular basis to account for growth patterns, regulatory requirement, or other needs. (7-1-26)
18. Facility and Design Standards. Facility and design standards are described in Sections 400 through 599 and must be followed in the planning, design, construction, and review of municipal wastewater facilities. (7-1-26)
19. Force Main. Pressurized pipeline for the purpose of conveying wastewater within a collection system or treatment facility. (7-1-26)
20. Gray Water. Domestic wastewater that does not contain blackwaste. (7-1-26)
21. Industrial Wastewater. Any waste, together with such water as is present, that is the by-product of industrial processes including, but not limited to, food processing or food washing wastewater. (3-31-22)
22. Land Application. A process or activity involving application of wastewater, surface water, or semi-liquid material to the land surface for the purpose of disposal, pollutant removal, or groundwater recharge. (7-1-26)
23. License. A document issued by the Idaho Division of Occupational and Professional Licenses certifying that an individual has met the appropriate qualifications and has authority to practice in Idaho under the provisions of Chapter 24, Title 54, Idaho Code. (7-1-26)
24. Material Deviation. A change from the design plans that significantly alters the type or location of facilities, requires engineering judgment to design, or impacts public safety or welfare. (7-1-26)
25. Material Modification. Those modifications of an existing wastewater system that increase system capacity or alter the methods or processes employed. Increasing system capacity occurs by increasing pumping capacity of a system or the number of service connections within the system. Altering methods or processes employed occurs by adding new or altering existing wastewater system components to satisfy an increase in wastewater flow of the system or changing engineering design intent of the wastewater collection or treatment system. Maintenance as outlined in the approved operation and maintenance manual, or maintenance that does not meet the criteria of a material modification described in this definition, is not a material modification. Like-kind replacement is not considered a material modification. (7-1-26)
26. Municipal Wastewater. Sewage and associated solids, whether treated or untreated, together with such water that is present. When incidental to flow and strength, industrial wastewater or other non-domestic sources may also be present. (7-1-26)
27. Non-Potable Mains. Pipelines that collect, deliver, or otherwise convey non-potable fluids from or to multiple service connections. (7-1-26)
28. Non-Potable Services. Pipelines that collect, deliver, or otherwise convey non-potable fluids from or to a non-potable main. These pipelines connect individual facilities to the non-potable main. This term also refers to pipelines that convey non-potable fluids from a pressurized irrigation system, recycled water system, and other non-potable systems to individual consumers. (7-1-26)
29. Nuisance. Anything which is injurious to the public health or an obstruction to the free use, in the customary manner, of any waters. (7-1-26)
30. Nutrients. The major substances necessary for the growth and reproduction of plant life consisting of nitrogen, phosphorus, and carbon compounds. (7-1-26)
31. Operating Personnel. Any person who is employed, retained, or appointed to conduct the tasks associated with the day-to-day operation and maintenance of a community wastewater system including persons making system control or system integrity decisions about water quantity or water quality that may affect public health. (7-1-26)
32. Owner. The person, company, corporation, district, association, or other organizational entity that
owns the wastewater system, and who provides, or intends to provide, wastewater service to system users and is ultimately responsible for the wastewater system operation. (7-1-26)
33. Pollutant. Dredged spoil, solid waste, incinerator residue, sewage, garbage, sewage sludge, munitions, chemical waste, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, silt, cellar dirt; and industrial, municipal and agricultural waste, gases entrained in water; or other materials which, when discharged to water in excessive quantities, cause or contribute to water pollution. Provided however, biological materials shall not include live or occasional dead fish that may accidentally escape into the waters of the state from aquaculture facilities. (3-31-22)
34. Potable Water. Water for human consumption. Also referred to as Water for Human Consumption or Drinking Water. (7-1-26)
35. Potable Mains. Pipelines that deliver potable water to multiple service connections. (3-31-22)
36. Potable Service. Pipelines that convey potable water from a connection to the potable water main to individual consumers. (7-1-26)
37. Preliminary Engineering Report (PER). Project specific design report for a new wastewater system or existing wastewater system undergoing material modifications. These reports address specific purpose and scope, design requirements, alternative solutions, costs, operation and maintenance requirements, and other requirements as described in Section 411. (7-1-26)
38. Primary Treatment. Processes or methods that serve as the first stage treatment of wastewater, intended for removal of suspended and settleable solids by gravity sedimentation; provides no changes in dissolved and colloidal matter in the sewage or waste flow. (7-1-26)
39. Private Wastewater Treatment Plant. A wastewater system that treats municipal wastewater and is under private ownership. These systems are typically initially owned, operated, and maintained by a developer with the ownership, operation and maintenance transferring to a homeowner’s association, or similar entity as lots are sold within the development. (7-1-26)
40. Community Wastewater System. A publicly or privately owned wastewater system that generates, collects, treats, stores, or disposes of two thousand five hundred (2,500) or more gallons of wastewater per day based on Average Day Flow measured in the system. For new wastewater systems not constructed, Average Day Flow may be estimated as documented in an approved PER. This does not include: (7-1-26)
a. Any animal waste system used for agricultural purposes that have been constructed in part or whole by public funds; or (3-31-22)
b. Any industrial or other nonmunicipal wastewater system which is covered under Section 401. (7-1-26)
41. Qualified Licensed Professional Engineer (QLPE). A professional engineer licensed by the state of Idaho; qualified by education or experience in the specific technical fields involved in these rules; and retained or employed by a city, county, quasi-municipal corporation, or regulated public utility for the purposes of plan and specification review. (3-31-22)
42. Quasi-Municipal Corporation. A public entity, other than community government, created or authorized by the legislature to aid the state in, or to take charge of, some public or state work for the general welfare. For the purpose of these rules, this term refers to wastewater or sewer districts. (3-31-22)
43. Receiving Waters. Those waters which receive pollutants from point or nonpoint sources. (3-31-22)
44. Recharge Water. Water specifically utilized for the purpose of adding water to the zone of saturation. (7-1-26)
45. Redundancy. Backup equipment and facilities to make the operation of the systems more reliable in emergency situations such as taking certain processes off-line or for treating spikes in wastewater flow or strength. (7-1-26)
46. Reliability. Based on the wastewater system’s ability to consistently handle the wastewater flows in the community and to meet the requirements of its permits and includes redundancy built into the wastewater infrastructure and proper maintenance of the system. (7-1-26)
47. Reasonably Accessible. The following criteria must be used to determine whether a project proposing a new private wastewater treatment plant, or a material modification of an existing private wastewater treatment plant, is reasonably accessible to a municipal wastewater collection system. (7-1-26)
a. For an existing private wastewater treatment plant, reasonably accessible means the municipal wastewater collection system becomes located within a minimum of one thousand (1,000) feet of any portion of the disposal piping of a private wastewater treatment plant, and the owner of the municipal wastewater collection system will provide a “will serve” letter. (7-1-26)
b. For a proposed project which includes a new private wastewater treatment plant, reasonably accessible means the municipal wastewater collection system is located within a minimum of one thousand (1,000) feet of any portion of the proposed development or existing development property boundary, and the owner of the municipal wastewater collection system will provide a “will serve” letter. (7-1-26)
c. The Department may determine that a private wastewater treatment plant may be reasonably accessible to the municipal wastewater collection system at distances greater than those distances specified in a. or b. above based on site-specific factors. (7-1-26)
48. Responsible Charge (RC). Active, daily on-site or on-call responsibility for the performance of operations or active, on-going, on-site or on-call direction of employees and assistants. (7-1-26)
49. Responsible Charge Operator. Operator is an operator licensed at a class equal to or greater than the classification of the system who has been designated by the system owner to have direct supervision of and responsibility for the performance of operations of specified wastewater treatment systems or wastewater collection systems and the direction of personnel employed or retained at the same system. The responsible charge operator has an active daily on-site or on-call presence at the specified facility. (7-1-26)
50. Reviewing Authority. For those projects requiring preconstruction approval by the Department, the Department is the reviewing authority. For those projects allowing for preconstruction approval by others, pursuant to Subsection 400.03.b., the Qualified Licensed Professional Engineer (QLPE) is also the reviewing authority. (7-1-26)
51. Secondary Treatment. Processes or methods for the removal of biodegradable organic matter (in solution or suspension) and suspended solids. May include the removal of biodegradable organics and nutrients (nitrogen, phosphorus, or both nitrogen and phosphorus). Disinfection may also be included in secondary treatment. (7-1-26)
52. Septage. Contents removed from septic tanks, portable vault toilets, privy vaults, wastewater holding tanks, very small wastewater treatment systems, or semi-public facilities (i.e., schools, motels, mobile home parks, campgrounds, small commercial endeavors) receiving wastewater from domestic sources. Non-domestic (industrial) wastes are not included in this definition. This does not include drinking water treatment residuals that may be held in a holding tank. (7-1-26)
53. Septage Transfer Station. A place where septage is accumulated for collection and subsequent removal without treatment. (7-1-26)
54. Service Connection. Point of connection between the utility’s system and the customer’s piping or premises, typically including the pipe, meter, valves, and appurtenances leading from the main to the customer’s
property line. (7-1-26)
55. Sewage. Water-carried human or animal waste from residences, buildings, industrial establishments or other places, together with such groundwater infiltration and surface water as may be present. (7-1-26)
56. Simple Wastewater Main Extension. New or replacement wastewater main(s) requiring plan and specification review per these rules and that will be connected by gravity, without the use of pumps or lift stations, to existing wastewater collection facilities that have the capacity to carry the additional wastewater flow and capacity at downstream treatment facilities to meet disposal requirements. (7-1-26)
57. Sludge. The semi-liquid mass produced and removed by municipal or nonmunicipal wastewater treatment processes. (7-1-26)
58. Substitute Responsible Charge Operator. A community wastewater operator holding a valid license at a class equal to or greater than the community wastewater system classification, designated by the system owner to replace and to perform the duties of the responsible charge operator when the responsible charge operator is not available or accessible. (7-1-26)
59. Surface Water Body. All surface accumulations of water, natural or artificial, public or private, or parts thereof which are wholly or partially within, which flow through or border upon the state. This includes, but is not limited to, rivers, streams, canals, ditches, lakes, and ponds. It does not include private waters as defined in Section 42-212, Idaho Code. (3-31-22)
60. Total Containment Lagoon. A wastewater lagoon that relies on evaporation for effluent disposal with no other permit to dispose. (7-1-26)
61. Treatment. A process or activity conducted for the purpose of removing pollutants from wastewater. (3-31-22)
62. Treatment Facility. Any physical facility or land area for the purpose of treating, neutralizing or stabilizing pollutants including treatment plants; the necessary conveyance, intercepting, outfall and outlet sewers; pumping stations integral to such plants or sewers; disposal or reuse facilities; equipment and furnishing thereof; and their appurtenances; also known as a treatment system, wastewater treatment system, wastewater treatment facility, or wastewater treatment plant. (7-1-26)
63. User. Any person served by a wastewater system. Also known as a service connection. (7-1-26)
64. Very Small Wastewater System. A community wastewater system that serves five hundred (500) service connections or less and includes a collection system with a system size of six (6) points or less on the system classification rating form and is limited to only one (1) or more of the following wastewater treatment processes: (7-1-26)
65. Wastewater. Any combination of liquid or water and pollutants from activities and processes occurring in dwellings, commercial buildings, industrial plants, institutions and other establishments, together with any groundwater, surface water, and storm water that may be present; liquid or water that is chemically, biologically, physically or rationally identifiable as containing blackwater, gray water or commercial or industrial pollutants; and sewage. (7-1-26)
66. Wastewater Flows. The following flows for the design year must be identified and used as a basis for design of wastewater systems including sewer mains, pumping stations, wastewater treatment plants, treatment units, and other wastewater handling facilities. (7-1-26)
a. Average Day Flow. The average day flow is the average of daily volumes to be received for a continuous twelve (12) month period expressed as a volume per unit time. However, the average day flow for design purposes for facilities having critical seasonal high hydraulic loading periods, such as recreational areas or industrial facilities, will be based on the average day flow during the seasonal period. (7-1-26)
b. Maximum Day Flow. The design maximum day flow is the largest volume of flow to be received during a continuous twenty-four (24) hour period expressed as a volume per unit time. (3-31-22)
c. Maximum Month Flow. The maximum month flow is the largest volume of flow to be received during any calendar month expressed as a volume per unit time. (3-31-22)
d. Peak Instantaneous Flow. The design peak instantaneous flow is the instantaneous maximum flow rate to be received. (3-31-22)
e. Peak Hour Flow. The design peak hour flow is the largest volume of flow to be received during a one (1) hour period expressed as a volume per unit time. (3-31-22)
67. Wastewater Lagoon. Manmade impoundments constructed with earthen or semi-permeable embankments with an impervious liner for the purpose of storing, treating, or disposing of wastewater or effluent. (7-1-26)
68. Wastewater Pumping Station. A wastewater facility that collects wastewater from the collection system or the treatment system and pumps it to a higher elevation. Also called lift station or wastewater lift station. (3-31-22)
69. Wastewater System. A collection system or treatment facility, or a combination of collection system and treatment facility. This includes all structures, equipment, or processes required to collect, convey, treat, store, and dispose of wastewater. (7-1-26)
70. Wastewater System Operator. The person employed, retained, or appointed to conduct the tasks associated with routine and emergency operation and maintenance of a community wastewater system to safeguard the public health and environment. (7-1-26)
01. Appropriate Control Measures. The Department, through approval or disapproval of plans and specifications for wastewater systems, the issuance of wastewater discharge permits, orders, compliance schedules, directives or any of the mechanisms at its disposal, will require persons to apply appropriate control measures necessary to achieve and maintain the water quality standards contained in IDAPA 58.01.02, “Water Quality Standards,” or IDAPA 58.01.11, “Groundwater Quality Rule.” (7-1-26)
02. Degree of Treatment. The degree of wastewater treatment required to restore and maintain the standards of quality will be determined in each instance by the Department, based upon the following: (3-31-22)
a. The uses which are made or desired of the receiving water; (3-31-22)
b. The volume and nature of flow of the receiving water; (3-31-22)
c. The quantity and quality of the wastewater to be treated; and (3-31-22)
d. The presence or absence of other sources of water pollution on the same watershed, stream segment
or aquifer. (3-31-22)
03. Operation. Any person who owns or operates any wastewater system must at all times: (7-1-26)
a. Ensure that such facility is operated under competent supervision and with the highest efficiency that can reasonably be expected; (7-1-26)
b. Ensure that untreated or partially treated wastewater is not disposed of to the ground surface unless otherwise permitted or approved by the Department; and (7-1-26)
c. Maintain such facility in good repair. (3-31-22)
d. Maintain records as necessary to operate the wastewater system and document compliance. (7-1-26)
04. Falsification of Records. It is a violation of these rules for any person to falsify or knowingly render inaccurate any treatment record required under these rules. (7-1-26)
01. Classification. All community wastewater systems will be classified based on indicators of potential health risks. Classification of treatment and collection systems govern the level of licensure and operator training necessary to ensure proper operation and maintenance of a community wastewater system. Licensure is governed by the Division of Occupational and Professional Licensing rules at IDAPA 24.05.01. (7-1-26)
a. Classification rating forms developed in accordance with the criteria in Subsection 202.02 must be completed by the community wastewater system owner or designee at the time the wastewater system is in operation for every community wastewater treatment facility and wastewater collection system. Community wastewater treatment and wastewater collection system owners or designee must submit additional classification rating forms at five (5) year intervals or when directed by the Department to submit a revised classification rating form. (7-1-26)
b. The Department will review system classification rating forms and issue the final system classification. (7-1-26)
02. Classification Criteria. The following criteria will be used to classify community wastewater systems: (7-1-26)
a. Complexity, size, volume, and variability in raw waste for treatment systems using guidelines established by the Department. (7-1-26)
b. Complexity or size of collection systems. (3-31-22)
c. Other criteria necessary to completely classify systems. (7-1-26)
01. System Operator Licensure. Owners of all community wastewater systems must place the direct supervision of their wastewater systems, including each treatment system and each collection system or each very small wastewater system, under the responsible charge of an operator who holds a valid license issued by the Idaho Division of Occupational and Professional Licenses equal to or greater than the classification of each treatment system and each collection system or each very small wastewater system. An operator in responsible charge of both a wastewater treatment system and a collection system must hold two (2) licenses, one (1) for wastewater treatment and one (1) for collection, except for a very small wastewater system for which the responsible charge operator may hold a single very small wastewater system license. When the responsible charge operator is not available, the community wastewater system owner must designate a substitute responsible charge operator. Owners must notify the Department in writing of any change of responsible charge or substitute responsible charge operator within thirty (30) days of such change. (7-1-26)
a. Community wastewater system operating personnel that exclusively operate a Class A Recycled Water Distribution System in accordance with IDAPA 58.01.17, “Recycled Water Rules,” are not subject to operator licensure requirements as outlined in these rules. (7-1-26)
b. Any non-pressurized drainfield and associated septic tank and collection system operating personnel are not subject to operator licensure requirements. (3-31-22)
Community wastewater systems may contract with properly licensed operating personnel to provide responsible charge operators and substitute responsible charge operators. Proof of such contract must be submitted to the Department prior to the contracted operating personnel performing any services at the community wastewater system. (7-1-26)
For permitting and approval processes for subsurface sewage disposal see IDAPA 58.01.03, “Individual/Subsurface Sewage Disposal Rules and Rules for Cleaning of Septic Tanks.” (7-1-26)
Plans and specifications for municipal wastewater systems must comply with the facility and design standards set forth in Sections 410 through 599. The plans and specifications must contain sufficient detail to allow for the construction of the wastewater systems. If design issues are not addressed by the facility and design standards, then guidance documents, some of which are listed in Section 008, may be used as guidance in the design and review of the plans and specifications. See also Section 007. (7-1-26)
01. Ownership. Documentation of the ownership and responsibility for operating the proposed wastewater system must be made available to the Department prior to or concurrent with the submittal of plans and specifications described in Subsection 400.03. The documentation must demonstrate financial arrangements adequate for construction, operation, and maintenance of the system. Documentation must also include the name of the wastewater system owner; the name, address, and phone number of the wastewater treatment facility; and the name, address, and phone number of the responsible charge operator. This information may be presented in a “will serve” letter described in Subsection 400.02. (7-1-26)
02. Will Serve Letter. If the proposed project connects to an existing wastewater system, a letter from the existing wastewater system must be submitted to the Department stating that the existing wastewater system is able to and will provide services to the proposed project and that the wastewater system has reviewed and accepted the proposed construction plans and specifications subject to Department review and approval. The Department may require further documentation showing the ability of the existing wastewater system to provide service to the proposed project. This letter must be submitted prior to or concurrent with the submittal of plans and specifications described in Subsection 400.03. (7-1-26)
a. Except as provided in Subsection 400.03.b., all plans and specifications for the construction of new municipal wastewater systems, or material modifications to existing municipal wastewater systems must be submitted to the Department for review and approval before construction may begin and all construction must be in substantial compliance. This does not include plan and specifications for facilities for sludge disposal but does include plans and specifications for treatment or storage of sludge. The Department will review plans and specifications in accordance with timelines set forth in Section 39-118, Idaho Code. If construction is not completed within twelve (12) months of the Department’s final approval, an extension or re-approval must be obtained from the Department. The Department may require re-submittal of all or part of the plans and specifications prior to issuing an
extension or re-approving the plans and specifications. The Department may, at its discretion, issue an approval or re-approval for a duration of more than twelve (12) months based on documentation provided by the design engineer that completion of construction is anticipated to be more than twelve (12) months. No material deviation may be made to the approved plans and specifications without the prior approval of the Department. (7-1-26)
b. Plans developed for simple wastewater main extensions do not require preconstruction approval by the Department when such facilities will be owned and operated by a city, county, quasi-municipal corporation or regulated public utility, provided that such plans and specifications are reviewed and approved by a QLPE to verify compliance with these rules prior to initiation of construction. At the discretion of the city, county, quasi-municipal corporation or regulated public utility, the plans addressed by this subsection may be referred to the Department for review and approval prior to initiation of construction. The Department has the authority to review plans and specifications approved by a QLPE and can require modifications if the plans and specifications do not meet facility and design standards. Any plans and specifications approved pursuant to this subsection must be transmitted to the Department at the time construction is authorized and must be marked or stamped as “Approved for Construction.” The plans and specifications must be sealed, signed, and dated by the professional engineer in responsible charge of their preparation, and the approval or transmittal letter must be sealed, signed, and dated by the QLPE that is approving the plans and specifications. Along with the plans and specifications, the transmittal must include the following statements. (7-1-26)
i. The author of the transmittal letter is the QLPE representing the city, county, quasi-municipal corporation or regulated public entity. (7-1-26)
ii. The extension project complies with the current facility plan or PER, or a statement that the wastewater system has adequate capacity. (7-1-26)
iii. The city, county, quasi-municipal corporation or regulated public entity or its authorized agent that the wastewater system owner will serve the project. (7-1-26)
iv. The city, county, quasi-municipal corporation or regulated public entity or its authorized agent that the wastewater system owner will own and operate the project after construction is complete. (7-1-26)
v. The QLPE approved plans and specifications for construction. (7-1-26)
vi. The QLPE ensures plans and specifications comply with the facility standards within these rules. (7-1-26)
vii. Recommending whether sanitary restrictions can be released or should remain in force. (7-1-26)
c. A QLPE may approve: (7-1-26)
i. Plans and specifications for simple wastewater main extensions that will be able to dispose to an existing wastewater system owned by a city, county, quasi-municipal corporation, or regulated public utility at the time the extension is approved for construction by the QLPE; (7-1-26)
ii. Plans for simple wastewater main extensions which will dispose to an existing wastewater system owned by a city, county, quasi-municipal corporation, or regulated public utility, but are unable to connect to the wastewater system at the time the extension is approved for construction by the QLPE, provided sanitary restrictions remain in force for the proposed extension; and (7-1-26)
iii. A design that was prepared by a subordinate engineer or an engineer from a separate design group within the city, county, quasi-municipal corporation, or regulated public utility if the QLPE is employed by a city, county, quasi-municipal corporation, or regulated public utility. (7-1-26)
d. A QLPE may not approve: (7-1-26)
i. Plans and specifications which include mechanical systems such as wastewater pumping stations, force mains, or treatment facilities; (7-1-26)
ii. Plans and specifications which the QLPE was the design engineer or otherwise involved in the design; and (7-1-26)
iii. Plans and specifications designed by the company with which the QLPE is employed if the QLPE is not employed by a city, county, quasi-municipal corporation or regulated public utility. (7-1-26)
04. Engineer’s Seal. Plans and specifications submitted to the Department for the construction or material modification of wastewater systems must be prepared by or under the supervision of an Idaho licensed professional engineer and must be sealed, signed, and dated by the professional engineer in responsible charge of their preparation. (7-1-26)
05. Record Plans and Specification. (3-31-22)
a. Must be submitted to the Department as specified in Section 39-118(3), Idaho Code. (7-1-26)
b. Record plans and specifications, or a statement submitted in lieu of record plans and specifications, must be sealed, signed, and dated by the professional engineer in responsible charge of their preparation. (3-31-22)
06. Compliance With Applicable Standards and Rules. All plans and specifications submitted must be in compliance with these rules and conform in style and quality to regularly accepted engineering standards. (7-1-26)
07. Exception. The Department may waive the plan and specification approval for any facility or category of facilities which will have no significant impact on the environment or public health. (7-1-26)
08. Department Approval On-site During Construction. The owner must maintain one (1) copy of the approved plans and specifications and the approval letter from the reviewing authority on-site during construction at all times. (7-1-26)
09. Construction Inspection. Except as provided in Subsection 400.03.b., construction may not commence until all necessary approvals have been received from the Department. The owner must ensure an Idaho licensed professional engineer can confirm material compliance with the approved plans and to produce accurate record documents as described in Subsection 400.05. (7-1-26)
01. Plan and Specification Approval. The Department reviews nonmunicipal wastewater system plans and specifications external to in-plant processes to ensure compliance with this chapter. The construction of any new, or material modification of an existing, nonmunicipal wastewater system must not begin before plans and specifications for the proposed facility have been submitted to and approved by the Department. Aquaculture facilities must submit plans and specifications for construction, modification, or expansion of waste treatment or disposal facilities for review and approval consistent with Section 39-118(5), Idaho Code. Infrastructure for water conveyance or aquatic organism husbandry within an aquaculture facility, prior to its discharge or diversion to waste treatment or disposal facility, does not require engineering design submittal under these rules. (7-1-26)
02. Deviations from Approved Plans. No material deviations may be made from the approved plans and specifications without prior approval from the Department. (7-1-26)
03. Engineer’s Seal. Plans and specifications submitted to the Department must be prepared by or under the supervision of an Idaho licensed professional engineer and be sealed, signed, and dated by the professional engineer in responsible charge of their preparation. Construction must be observed by an Idaho licensed professional engineer or a person under the supervision of an Idaho licensed professional engineer. (7-1-26)
04. Record Plans and Specifications. (3-31-22)
a. Must be submitted to the Department as specified in Section 39-118(3), Idaho Code. (7-1-26)
b. Record plans and specifications, or a statement submitted in lieu of record plans and specifications, must be sealed, signed, and dated by the professional engineer in responsible charge of their preparation. (3-31-22)
05. Exception. The Department can waive the plan and specification approval described in Subsection 401.01 for any facility or category of facilities which will have no significant impact on the environment or on public health. (7-1-26)
06. Department Approval On-site During Construction. The owner must maintain a copy of the approved plans and specifications and the approval letter from the Department on-site during construction at all times. (7-1-26)
07. Applicability of Standards. The facility and design standards for municipal wastewater systems set out in these rules do not apply to nonmunicipal wastewater systems covered under Section 401. All plans and specifications submitted pursuant to Section 401.01 must conform in style and quality to regularly accepted engineering standards and applicable guidance and include the basis of design information and applicable design criteria. (7-1-26)
No person may proceed, or cause to proceed, with construction of a new community wastewater system, a new private treatment plant, a new municipal wastewater treatment facility, or a new privately owned municipal wastewater pumping station until it has been demonstrated to the Department that the wastewater system will have adequate technical, financial, and managerial capacity. Demonstration of capacity must be submitted to the Department prior to, or concurrent with, the submittal of plans and specifications, as described in Section 39-118, Idaho Code, and Subsection 400.03. The Department will issue in writing its approval of the new system capacity demonstration. Existing wastewater systems incapable of demonstrating technical, financial, or managerial capacity as identified through operational problems, may be required to submit additional technical, financial, or managerial documentation to the Department for review and approval. (7-1-26)
01. Technical Capacity. To meet this provision, the system owner must submit documentation demonstrating: (7-1-26)
a. The system meets the relevant design, construction, and operating requirements of these rules; (3-31-22)
b. A plan is in place to deal with emergencies; (3-31-22)
c. A plan exists for replacement or improvement of infrastructure as necessary; and (3-31-22)
d. The system has trained personnel with an understanding of the technical and operational characteristics of the system. (3-31-22)
02. Financial Capacity. (7-1-26)
a. Documentation of financial capacity must include, but is not limited to: (7-1-26)
i. Organizational and financial arrangements adequate to construct and operate the wastewater system in accordance with these rules. This information can be provided by submitting estimated construction, operation, and maintenance costs, letters of credit, or other access to financial capital through public or private sources and, if available, a certified financial statement; (7-1-26)
ii. Revenue sufficiency, that includes, but is not limited to, billing and collection procedures; a proposed rate structure demonstrating the availability of operating funds; revenues for depreciation and reserves; and the ability to accrue a capital replacement fund. A preliminary operating budget must be provided; and (7-1-26)
iii. Adequate fiscal controls. (7-1-26)
b. For private wastewater treatment plants, a performance bond, maintenance bond, or cash reserve of one (1) year of operation and maintenance costs is required to ensure continuous and adequate operation and maintenance. (7-1-26)
03. Managerial Capacity. To demonstrate adequate managerial capacity, the system owner must submit at least the following information to the Department: (7-1-26)
a. Clear documentation of legal ownership and any plans that may exist for transfer of that ownership upon completion of construction or after a period of operation; (3-31-22)
b. The name, address, and telephone number of the person who will be accountable to ensure that the wastewater system follows these rules; (7-1-26)
c. The name, address, and telephone number of the responsible charge operator and the substitute responsible charge operator; (7-1-26)
d. A description of how the wastewater system will be managed. Information such as by-laws, restrictive covenants, articles of incorporation, or procedures and policy manuals which describe the management organizational structure must be provided; (7-1-26)
e. A description of staff qualifications, including training, experience, certification or licensing, and continuing education; (7-1-26)
f. An explanation of how the wastewater system will establish and maintain effective communications and relationships between the wastewater system management, its customers, professional service providers, and any applicable regulatory agencies; and (3-31-22)
g. Evidence of planning for future growth, equipment repair and maintenance, and longterm replacement of system components. (7-1-26)
04. Consolidation. In demonstrating new system capacity, the owner of the proposed new system must investigate the feasibility of obtaining wastewater service from an established wastewater system. If such service is available, but the owner elects to proceed with an independent system, the owner must explain why this choice is in the public interest in terms of environmental protection, affordability to wastewater users, and protection of public health. (7-1-26)
01. Facility Plans. Unless otherwise noted in this subsection, all new municipal wastewater systems and all existing municipal wastewater systems undergoing material modification are required to have a current facility plan that addresses all applicable issues specifically required in Sections 410 and 420 through 599. The facility plan must address these issues sufficiently to determine the effects of the project on the overall wastewater infrastructure. Facility plans must address the entire potential service area of the wastewater system. A facility plan may be completed for collection systems only, for treatment facilities only, or for both the collection system and the treatment facility. If such a collection system facility plan is prepared, and flows increase more than the design capacity of downstream collection and treatment facilities, the impact of the flow must be addressed in the facility plan. (7-1-26)
a. A facility plan is not required if the Department is provided documentation supporting the ability of the wastewater system to provide service for the simple wastewater main extension without adding wastewater pumping stations or treatment capacity to the treatment facility and without overloading the existing collection system. Documentation may be in the form of: (7-1-26)
i. Hydraulic modeling; (3-31-22)
ii. Usage data and flow calculations; (3-31-22) iii. Declining balance reports that demonstrate the wastewater system has the capacity to supply the service area of the system served by the extension; or (7-1-26) iv. Other documentation acceptable to the Department. (3-31-22)
b. A Department-approved facility plan is not required to be in place prior to the QLPE approving simple wastewater main extensions pursuant to Subsection 400.03.b., provided that the system is in compliance with the facility and design standards in the area served by the extension. If the Department has not approved a facility plan which covers the proposed simple wastewater main extension, then the system owner or the QLPE must include with the transmittal letter documentation supporting the ability of the system owner to provide service for the simple wastewater main extension without adding wastewater pumping stations or treatment capacity to the system and without overloading the existing collection system. The system owner must provide this documentation to the QLPE as necessary. Documentation may be in the form of: (7-1-26)
i. Hydraulic modeling; (3-31-22) ii. Usage data and flow calculations; (3-31-22) iii. Declining balance reports that demonstrate the system has the capacity to supply the service area of the system served by the extension; or (3-31-22) iv. Other documentation acceptable to the Department. (3-31-22)
02. Submittal to Department. Facility plans must be submitted to the Department for review and approval prior to the submission of plans and specifications for a project related to the facility plan. (7-1-26)
03. Engineer's Seal. Facility plans submitted to the Department must be sealed, signed, and dated by the professional engineer in responsible charge of their preparation. (7-1-26)
04. Facility Plan Contents. The facility plan must assemble basic information, present criteria and assumptions, address hydraulic capacity, treatment capacity, and operation and maintenance considerations, and examine alternative solutions with preliminary layouts, cost estimates, and project financing. The facility plan is intended to address system wide growth, to identify system deficiencies, and to lay out a plan for system upgrades and expansion. The minimum requirements for a facility plan are in Subsections 410.04.a. through 410.04.c. If specific items are not applicable to a particular facility plan, then the engineer must state this in the facility plan and state the reason why it is not applicable. (7-1-26)
a. The facility plan for a new wastewater system must include sufficient detail to support the provisions of Sections 410 through 520 and address these items: (7-1-26)
i. Provide a general description and location of the system including service boundaries; (7-1-26) ii. Provide the estimated design population and service connections expressed as EDUs of the system; (7-1-26) iii. Provide design data for domestic, commercial, and industrial wastewater generation, including average day, maximum day, maximum month, or peak hour flows; (7-1-26) iv. Identify and describe any anticipated or proposed wastewater collection systems. Include specific details on any anticipated or proposed wastewater pumping stations and on any anticipated or proposed wastewater interceptor or trunk lines; (7-1-26) v. Identify and describe any anticipated or proposed treatment facilities. Provide specific detail on the type and level of treatment and the required capacity of the treatment facility; (7-1-26)
vi. Identify and describe any anticipated or proposed wastewater disposal system(s). Include specific information on the location and method of disposal and information on any existing disposal permits or estimated timelines to obtain anticipated required permits; and (7-1-26)
vii. Describe the drinking water distribution system with reference to the relationship to existing or proposed wastewater structures which may affect the operation and location of the wastewater system. (7-1-26)
b. The facility plan for an existing wastewater system must include sufficient detail to support the provisions of Sections 410 through 520, address all items in Subsections 410.04.a.i. through 410.04.a.viii., and the following: (7-1-26)
i. Provide a system-wide hydraulic analysis of the collection system unless otherwise approved by the Department. Any hydraulic analysis of an existing collection system must be properly calibrated. The type and sophistication of the hydraulic analysis will be dependent on the type of the wastewater system; (7-1-26)
ii. Identify and evaluate problems or deficiencies related to the wastewater system; (7-1-26)
iii. Identify the design capacity of existing facilities and the current operating flows; (7-1-26)
iv. Identify if two (2) or more wastewater systems will become one operating under the same governance, management, and financial functions including the physical interconnection of two or more wastewater systems; (7-1-26)
v. Describe financing options for projects identified in the facility plan; (7-1-26)
vi. Set forth anticipated charges for users; (7-1-26)
vii. Review organizational and staffing requirements; (7-1-26)
viii. Offer project recommendations for client consideration; and (7-1-26)
ix. Outline official actions and procedures to implement the project. (3-31-22)
c. If the project is funded by the state revolving fund or a state grant, the facility plan must meet the provisions of Subsections 410.04.a. and 410.04.b., and other requirements that may also apply. See IDAPA 58.01.12, “Rules for Administration of Wastewater and Drinking Water Loan Funds,” and IDAPA 58.01.22, “Rules for Administration of Planning Grants for Drinking Water and Wastewater Facilities.” (7-1-26)
d. A checklist which can be used for guidance can be found on the DEQ website at http://www.deq.idaho.gov. This checklist is for Department grant and loan projects, but may be used in part or in whole as a guide to assist in the development of any facility plan. (7-1-26)
01. Preliminary Engineering Reports (PERs). PERs are required for municipal wastewater system projects that require plan and specification review and approval pursuant to Subsection 400.03 and must address all applicable issues specifically required in Sections 411 through 599. PERs must be completed for wastewater collection system projects, all pump station projects, all treatment facility designs and upgrades, and all septage transfer stations. PERs are not required for simple wastewater main extensions that are approved in accordance with Subsections 410.01.a. or 410.01.b. (7-1-26)
02. Submittal to Reviewing Authority. PERs must be submitted to the Department for review and approval prior to the submission of plans and specifications. (7-1-26)
03. PER Contents. The PER must include sufficient detail to demonstrate that the proposed project
meets applicable design criteria. The PER generally addresses project specific issues rather than the overall system-wide plan. The PER must identify and evaluate wastewater related problems; assemble basic information; present design criteria and assumptions; examine alternative solutions with preliminary layouts and cost estimates; offer a conclusion with a proposed project; and outline official actions and procedures to implement the project. The items included in Subsections 411.03.a. through 411.03.c., and other items specifically described in Sections 426 through 599 must be addressed in detail in the PER. If specific items are not applicable to a particular design, then the designer must state this in the PER and state the reason why it is not applicable. Items adequately addressed in the facility plan under which the project is being designed, may be addressed by reference for purposes of the PER.
(7-1-26)
c. Items applicable to PERs for wastewater pump station projects include all items listed in Subsection 411.03.a. and the following: (7-1-26)
i. The PER must discuss and present the design criteria applicable to the proposed project. The design criteria includes, but is not limited to: (7-1-26)
(1) Wastewater flow rates including average day, maximum day, and peak hour flows; (3-31-22) (2) Influent wastewater characteristics, including characteristics during periods of wet weather flows; (3-31-22) (3) Size and configuration; (7-1-26)
(a) Friction losses through force mains must be based on the Hazen and Williams formula or other acceptable methods. When the Hazen and Williams formula is used, the friction losses for varying values of “C” must be evaluated for different types and ages of pipe; and (7-1-26)
(b) When initially installed, force mains will have a significantly higher “C” factor. The effect of the higher “C” factor must be considered in calculating maximum power requirements and duty cycle time to prevent damage to the motor. The effects of higher discharge rates on selected pumps and downstream facilities must also be considered; and (7-1-26)
(4) Redundancy provisions. (3-31-22)
ii. The PER must describe the proposed site and layout of the wastewater pumping station. This information includes, but is not limited to: (7-1-26)
(1) Currently proposed facilities; (3-31-22) (2) Geotechnical investigation and provisions including buoyancy calculations if required; (3-31-22) (3) Flood control provisions; (3-31-22) (4) Security; (3-31-22) (5) Operations and maintenance assessments; and (3-31-22) (6) Odor management plans. (3-31-22)
iii. The PER must discuss instrumentation and control that will be provided. This information includes, but is not limited to: (7-1-26)
(1) System configuration; (3-31-22) (2) Operator interface; (3-31-22) (3) Process and instrumentation diagrams; (7-1-26) (4) Alarm systems. (3-31-22)
iv. The PER must describe how the system will be operated during power outages, equipment failures, or other unforeseen system failures. (7-1-26)
d. Items applicable to PERs for wastewater treatment facility designs and upgrades include all items listed in Subsection 411.03.a., Subsection 411.03.c., and the following: (7-1-26)
i. The PER must discuss and present the design criteria applicable to the proposed project. The design criteria includes, but is not limited to: (7-1-26)
(1) Wastewater flow rates including average day, maximum day, maximum month, and peak hour flows; (3-31-22) (2) Effluent requirements; (3-31-22) (3) Solids production, disposal, or recycling requirements; (3-31-22) (4) Process units design criteria, process selection, and support data; (3-31-22) (5) Mass balance calculations for process units including, but not limited to, flow and solids; and (3-31-22) (6) Monitoring and reporting requirements. (3-31-22)
ii. The PER must describe the proposed site and layout of the treatment facilities. This information includes, but is not limited to: (7-1-26)
(1) Currently proposed facilities; (3-31-22) (2) Facilities for twenty (20) year design conditions; (3-31-22) (3) Facilities for build-out conditions; (3-31-22) (4) Space for facilities potentially necessary to meet higher levels of treatment; (3-31-22) (5) Liquid process facilities and conveyance; (3-31-22) (6) Sludge process facilities and conveyance; (7-1-26) (7) Plant access and on-site roads and walkways; (3-31-22) (8) Process piping and utilities; (3-31-22) (9) Buffer zones; (3-31-22) (10) Landscaping; (3-31-22) (11) Administration and operations buildings; (3-31-22) (12) Onsite laboratory facilities; and (3-31-22) (13) Treatment during construction and proposed unit bypassing requirements in accordance with applicable disposal permits. (7-1-26)
iii. The PER must provide a hydraulic profile for the proposed treatment facilities. This information includes, but is not limited to: (7-1-26)
(1) Twenty (20) year design facilities; (3-31-22) (2) Provision for higher levels of treatment; (3-31-22) (3) Receiving stream one hundred (100) year surface water elevation; and (3-31-22) (4) Hydraulics and pipe sizing for build-out conditions. (3-31-22)
iv. The PER must describe in detail the proposed process units and discuss how the proposed units will interface with any existing process units. This information includes, but is not limited to: (7-1-26)
(1) Current project and twenty (20) year design and build-out conditions; (3-31-22) (2) Size and number of units and loading rates; (3-31-22) (3) Redundancy provisions; (3-31-22) (4) Equipment type, size, performance criteria, and power requirements; (3-31-22) (5) Structure, equipment, and piping layout; (3-31-22) (6) Special code requirements; (3-31-22) (7) Cold temperature operation; and (3-31-22) (8) Procedures required for initial start-up of process unit(s), including procedures for handling initial system flows that are less than minimum flow requirements for the process unit(s). (7-1-26)
04. Engineer's Seal. PERs submitted to the Department must be sealed, signed, and dated by the professional engineer in responsible charge of their preparation. (7-1-26)
412. -- 424. (RESERVED)
425. FACILITY AND DESIGN STANDARDS FOR MUNICIPAL WASTEWATER SYSTEMS: OPERATION AND MAINTENANCE MANUALS.
01. Manual Contents. An operation and maintenance manual or manuals must be developed for all wastewater systems and include, but not limited to, the following contents: daily operating instructions, operator safety and emergency response procedures, location of valves and other key system features, a parts list and parts order forms, maintenance schedule, and information for contacting the responsible charge operators. An operational trouble-shooting section must be supplied to the wastewater system as part of any proprietary unit installed in system's facilities. (7-1-26)
02. Approval. Final operation and maintenance manuals for new construction or material modification of wastewater systems that include pumping stations or treatment facilities must be submitted to the Department for review and approval prior to start-up of the proposed system unless the system components are already covered in an existing manual. (7-1-26)
426. -- 429. (RESERVED)
430. FACILITY AND DESIGN STANDARDS FOR MUNICIPAL WASTEWATER SYSTEMS -- DESIGN AND CONSTRUCTION OF WASTEWATER PIPELINES.
01. Design Capacity. Sewer capacities must be designed for the estimated buildout flow, except in considering parts of the systems that can be readily increased in capacity. (7-1-26)
02. Details of Design and Construction. (3-31-22)
a. Minimum pipe size for gravity sewer mains must be eight (8) inches in diameter. Minimum pipe size for gravity sewer services must be four (4) inches in diameter. Pipe diameters larger than these minimums must be based on cleaning capability and hydraulic capacity and conform with the required planning documents. (7-1-26)
b. Wastewater pipelines must be installed sufficiently deep or specifically designed to prevent freezing and to protect the facilities from surface loading. (7-1-26)
c. Buoyancy of wastewater pipelines must be considered and flotation of the pipe must be prevented with appropriate construction where high groundwater conditions are anticipated. (7-1-26)
d. Gravity wastewater pipelines must be designed to have sufficient slope and velocity to “selfclean” or transport constituent solids to the treatment facility. (7-1-26)
i. If the current or future ownership of the system is by a city, county, quasi-municipal corporation or regulated public utility and the velocities are less than selfcleaning, the owner must, as a condition of the Department’s approval of plans and specifications, provide justification for the lower velocities and commit to, at a minimum, annually service wastewater pipelines to flush, transport, or remove solids from wastewater pipelines. This would include the use of cutting tools for roots, Vactor trucks, and any other method required to keep the pipelines clean, intact and flowing. That commitment must be in the form of a letter from both the owner and the future owner entity stating said commitment and must include a discussion of the current and future owners’ capacity to complete annual servicing. (7-1-26)
ii. If the owner is a developer that is passing the operation and maintenance on to a homeowner’s association or other similar entity, the design may not allow for velocities that are less than selfcleaning. (7-1-26)
e. Materials. (3-31-22)
i. The material selected should be adapted to local conditions, such as: character of industrial wastes, possibility of septicity, soil characteristics, exceptionally heavy external loadings, abrasion, corrosion, and similar problems. (7-1-26)
ii. Couplings complying with applicable standard specifications must be used for joining dissimilar materials. (7-1-26)
iii. For new pipe materials for which standards have not been established, the design engineer must provide complete pipe specifications and installation specifications developed on the basis of criteria adequately documented and certified in writing by the pipe manufacturer to be satisfactory for the specific application. (7-1-26)
f. Installation specifications must contain appropriate requirements based on the criteria, standards, and requirements established by industry in its technical publications. For assistance in designing such specifications, see “Idaho Standards for Public Works Construction,” referenced in Section 008. (7-1-26)
g. Joints and Infiltration. (3-31-22)
i. The installation of joints and the materials used must be included in the specifications. Wastewater pipeline joints must be designed to minimize infiltration and to prevent the entrance of roots throughout the life of the system. For assistance in designing such specifications, see “Idaho Standards for Public Works Construction,” referenced in Section 008. (7-1-26)
ii. Service connections to the wastewater pipeline main must be watertight and not protrude into the wastewater pipelines. If a saddle type connection is used, it must be a device designed to join with the types of pipe which are to be connected. All materials used to make service connections must be compatible with each other and with the pipe materials to be joined and must be corrosion proof. (7-1-26)
h. Manholes must be installed at the end of each line; at all changes in grade, size, or alignment; at all intersections. Cleanouts may not be used unless otherwise approved by the Department and may not be substituted for manholes nor installed at the end of laterals greater than one hundred fifty (150) feet in length. (7-1-26)
i. Testing must conform with Section 501.3.4 of the “Idaho Standards for Public Works Construction,” incorporated by reference in Section 004. (7-1-26)
j. Inverted siphons may not have less than two (2) barrels or pipes and will be provided with necessary appurtenances for maintenance, convenient flushing, and cleaning equipment. Design must provide
sufficient head and appropriate pipe sizes to secure sufficient velocities for design flow. (7-1-26)
k. The top of all wastewater pipelines entering or crossing surface water bodies must be at a sufficient depth below the natural bottom of the bed or otherwise designed to protect the wastewater pipeline. (7-1-26)
i. Wastewater pipelines located adjacent to surface water bodies must be located outside of the bed and sufficiently removed therefrom to provide for future possible stream widening and to prevent pollution by siltation during construction. (7-1-26)
ii. Wastewater pipeline outfalls, headwalls, manholes, gate boxes, or other structures must be designed to address anticipated flood flows of the surface water bodies. (7-1-26)
iii. Wastewater pipelines crossing surface water bodies should be designed to cross the surface water body as nearly perpendicular to the surface water body flow as possible and must be free from change in grade. (7-1-26)
iv. Wastewater pipelines entering or crossing surface water bodies must be constructed of water transmission pressure rated pipe with restrained joints conforming to Section 401.2.9 of the “Idaho Standards for Public Works Construction,” incorporated by reference in Section 004, or other suitable pipe with restrained joints capable of being installed to remain watertight and free from changes in alignment or grade. Material used to back-fill the trench must be concrete slurry, stone, coarse aggregate, washed gravel, or other materials which will not readily erode, cause siltation, damage pipe during placement, or corrode the pipe. (7-1-26)
v. Construction methods that will minimize siltation and erosion must be employed. (7-1-26)
l. Support must be provided for all joints in pipes utilized for aerial crossings. Restrained joints or structural casings are required. (7-1-26)
m. There may be no physical connections between a public or private potable water supply system and a wastewater pipeline, or appurtenance thereto, which would permit the passage of any wastewater or polluted water into the potable supply. No water pipe may pass through or contact any part of a wastewater pipeline manhole. (7-1-26)
n. When wastewater pipelines are proposed in the vicinity of any existing public or private drinking water sources or supplies or other drinking water facilities, excluding potable pipelines, the following separation distances must be maintained. (7-1-26)
i. Pressure wastewater mains will not be closer horizontally than one hundred (100) feet. (7-1-26)
ii. Gravity wastewater mains will not be closer horizontally than fifty (50) feet. (7-1-26)
iii. Wastewater service lines will not be closer horizontally than fifty (50) feet from any public water system source. (7-1-26)
iv. Wastewater service lines will not be closer horizontally than twenty-five (25) feet from private drinking water sources and other drinking water facilities. (7-1-26)
o. The requirements for the protection of potable pipelines from contamination by non-potable pipelines are described in Subsections 430.02.o.ii. and 430.02.o.iii. For this subsection, the term “pipeline” applies to both mains and services. Raw water pipelines must meet equivalent separation distances of Subsections 430.02.o.ii. through 430.02.o.iv. from either potable or non-potable pipelines. (7-1-26)
i. Alternative separation distances may be considered for Subsections 430.02.o.ii. through 430.02.o.iii. on a case-by-case basis when considering constructability, public health risk, environmental risk, and cost. The design engineer must submit data to the Department for review and approval showing that the proposed installation will be protective of public health and the environment. (7-1-26)
431. -- 439. (RESERVED)
01. General. Section 440 regulates municipal wastewater collection pump stations and not individual residence pump stations, individual residence grinder pump stations, or individual residence septic tank effluent pump stations. See Section 441 for regulation of those types of pump stations. (7-1-26)
a. Wastewater pumping station structures and electrical and mechanical equipment must be protected from physical damage by the one hundred (100) year flood. Wastewater pumping stations must remain fully operational and accessible during the twenty-five (25) year flood. Regulations of state and federal agencies regarding flood plain obstructions shall be considered. (7-1-26)
b. The pumping station must be accessible by maintenance vehicles during all weather conditions. (7-1-26)
c. The wet well and pump station piping must be designed to avoid operational problems from the accumulation of grit. (7-1-26)
d. Provisions must be made to consider the protection of maintenance personnel and visitors from typical and foreseeable hazards in accordance with the engineering standards of care. See also Subsection 450.07. (7-1-26)
02. Design. Design of wastewater pumping stations must meet the applicable provisions of Subsections 440.02.a. through 440.02.i. (7-1-26)
a. Construction materials used for pumping station structures must be appropriate under conditions of exposure to hydrogen sulfide and other corrosive gases, greases, oils, and other constituents frequently present in wastewater. (7-1-26)
i. Dry wells must be completely separated from the wet well. Common walls must be gas tight. (7-1-26)
ii. Provisions must be made to facilitate removing pumps, motors, and other mechanical and electrical equipment. Individual pump and motor removal must not interfere with the continued operation of remaining pumps. Suitable means of access for maintenance personnel wearing self-contained breathing apparatus must be provided to dry wells and to wet wells. See also Subsection 450.07. (7-1-26)
iii. Where high groundwater conditions are anticipated, buoyancy of the wastewater pumping station structures must be considered and, if necessary, adequate provisions made for protection. (7-1-26)
iv. Dry wells must be equipped with a positive means for dewatering. (7-1-26)
b. Multiple pumps must be provided. Pumps must have capacity such that, with any pump out of service, the remaining pumps will have capacity to handle the design peak hour flow. (7-1-26)
i. Pumps (except screw pumps) handling separate sanitary wastewater from thirty (30) inch or larger diameter sewers must be protected by bar racks. Appropriate protection from clogging must also be considered for small pumping stations. (7-1-26)
ii. Pumps handling unscreened raw wastewater must be capable of passing spheres of at least three (3) inches in diameter. Pump suction and discharge openings must be at least four (4) inches in diameter. An exception to the requirement for passing solid spheres of at least three (3) inches in diameter may be made on a case-by-case basis when approved by the Department based on equivalent protection from clogging or damage, such as grinder pumps. (7-1-26)
iii. The pump must be placed so that, under normal operating conditions, it will operate under a positive suction head, except as specified in Subsection 440.03. (7-1-26)
iv. Electrical equipment must comply with local and state codes. (7-1-26)
v. Design of intakes may use American National Standard Institute/Hydraulic Institute ANSI/HI 9.8, American National Standard for Centrifugal and Vertical Pump Intake Design. (7-1-26)
vi. The pumps and controls must be designed to operate with varying wastewater flows into the wet well. The pump control system design must account for, and minimize, downstream impact of pump discharge hydraulic surges. The station design capacity must be based on peak hourly flow as determined in accordance with Section 411 and must be adequate to maintain a velocity in the force main sufficient to avoid solids deposition. (7-1-26)
c. Water level control sensing devices must be designed to allow for automatic control of pumps. (7-1-26)
d. Suitable shutoff and check valves must be placed on the discharge line of each pump (except on screw pumps). The check valve must be located between the shutoff valve and the pump. Check valves must be suitable for the material being handled and placed on the horizontal portion of the discharge piping except for ball checks, which may be placed in the vertical run. Valves must be capable of withstanding normal pressure and water hammer. All shutoff and check valves must be operable from the floor level and accessible for maintenance. Outside levers are recommended on swing check valves. (7-1-26)
e. Suitable shutoff valves must be placed on the suction lines of dry pit pumps. (7-1-26)
f. Wet Wells. (3-31-22)
i. The American National Standard Institute/Hydraulic Institute ANSI/HI 9.8, American National Standard for Centrifugal and Vertical Pump Intake Design may be used as a guidance for design of wet wells. (7-1-26)
ii. Covered wet wells must have provisions for air displacement to the atmosphere, such as an inverted “j” tube or other means. (7-1-26)
g. Adequate ventilation must be provided for all pump stations unless access is provided using confined space entry procedures. Where the dry well is below the ground surface, mechanical ventilation must be provided. If screens or mechanical equipment requiring maintenance or inspection are in the wet well, permanently installed ventilation must be provided. There may be no interconnection between the wet well and dry well ventilation systems. (7-1-26)
h. Suitable methods for measuring wastewater flow must be provided at all pumping stations. (7-1-26)
i. There may be no physical connection between any potable water supply and a wastewater pumping station which, under any conditions, might cause contamination of the potable water supply. If a potable water supply connection is made to the station, the connection must comply with IDAPA 58.01.08, “Idaho Rules for Public Drinking Water Systems.” (7-1-26)
03. Suction Lift Pump Stations - Special Considerations. Suction lift pumps must meet the applicable provisions of Subsection 440.02. (7-1-26)
a. Suction lift pumps must be of the self-priming or vacuum-priming type. Suction lift pump stations using dynamic suction lifts exceeding the limits outlined in Subsections 440.03.b. through 440.03.d. may be approved by the Department upon submission of factory certification of pump performance and detailed calculations indicating satisfactory performance under the proposed operating conditions. (7-1-26)
b. Self-priming pumps must be capable of rapid priming and re-priming at the “lead pump on” elevation. Self-priming and re-priming must be accomplished automatically under design operating conditions. (7-1-26)
c. Vacuum-priming pump stations must be equipped with dual vacuum pumps capable of automatically and completely removing air from the suction lift pump. The vacuum pumps must be adequately protected from damage due to wastewater. The combined total of dynamic suction lift at the “pump off” elevation and required net positive suction head at design operating conditions must not exceed twenty-two (22) feet. (7-1-26)
d. The pump equipment compartment must be above grade or offset and be effectively isolated from the wet well to prevent a hazardous and corrosive sewer atmosphere from entering the equipment compartment. Wet well access may not be through the equipment compartment and must be at least twenty-four (24) inches in diameter. Gasketed replacement plates must be provided to cover the opening to the wet well for pump units removed for servicing. Valving may not be in the wet well. (7-1-26)
04. Submersible Pump Stations - Special Considerations. Submersible pump stations must meet the applicable provisions of Subsection 440.02, except as modified in Subsection 440.04. (7-1-26)
a. Submersible pumps and motors must be designed specifically for raw wastewater use, including totally submerged operation during a portion of each pumping cycle. An effective method to detect shaft seal failure or potential seal failure must be provided. (7-1-26)
b. Submersible pumps must be readily removable and replaceable without personnel entering or dewatering the wet well, or disconnecting any piping in the wet well. (7-1-26)
c. Electrical equipment must comply with local and state codes. (7-1-26)
i. Electrical supply, control, and alarm circuits must be designed to provide strain relief and to allow disconnection from outside the wet well. Terminals and connectors must be protected from corrosion by location outside the wet well or through use of watertight seals. (7-1-26)
ii. The motor control center must be located outside the wet well, readily accessible, and be protected by a conduit seal or other appropriate measures to prevent the atmosphere of the wet well from gaining access to the control center. The seal must be located so that the motor may be removed and electrically disconnected without disturbing the seal. (7-1-26)
iii. Pump motor power cords must be designed for flexibility and serviceability under conditions of extra hard usage. Ground fault interruption protection must be used to de-energize the circuit in the event of any failure in the electrical integrity of the cable. Power cord terminal fittings must be corrosion-resistant and constructed to prevent the entry of moisture into the cable, provided with strain relief appurtenances, and designed to facilitate field connecting. (7-1-26)
d. Valves required under Subsection 440.02 must be in a separate valve chamber. Provisions must be made to remove or drain accumulated water from the valve chamber. The valve chamber may be dewatered to the wet well through a drain line with a gas and water tight valve. Check valves that are integral to the pump need not be in a separate valve chamber provided that the valve can be removed from the wet well in accordance with Subsection 440.04. Access must be provided in accordance with Subsection 440.02. (7-1-26)
05. Screw Pump Stations - Special Considerations. Screw pump stations must meet the applicable provisions of Subsection 440.02. (7-1-26)
a. Covers or other means of excluding direct sunlight must be provided as necessary to eliminate adverse effects from temperature changes. (7-1-26)
b. A positive means of isolating individual screw pump wells must be provided. (7-1-26)
c. Submerged bearings must be lubricated by an automated system without pump well dewatering.
(7-1-26)
06. Alarm Systems. Alarm systems with a backup power source must be provided for pumping stations. The alarm must be activated in cases of power failure, dry well sump and wet well high water levels, pump failure, pump clogging, unauthorized entry, or other cause of pump station malfunction. Pumping station alarms, including identification of the alarm condition, must be transmitted to a twenty-four (24) hour response center. Audio-visual alarm systems may be approved by the Department based upon location, station holding capacity, and inspection frequency. (7-1-26)
(3-31-22)
a. Emergency operation for pump stations is required to prevent the unintended discharge of raw or partially treated wastewater to any waters or land surface and to protect public health by preventing back up of wastewater and subsequent discharge to basements, streets, and other public and private property. (7-1-26)
b. Emergency pumping capability is required for all new pumping stations constructed after April 15, 2007. Emergency pumping capability is required for all existing pumping stations that undergo a material modification unless overall system reliability can be proven adequate to the Department as shown in Subsections 440.07.b.i. and 440.07.b.ii. (7-1-26)
i. System reliability is adequate for an existing pumping station undergoing material modification if power grid outages average three (3) or less per year based on data for the three (3) previous years with no more than six (6) outages in a single year. (7-1-26)
ii. Outage duration averages less than four (4) hours based on data for the three (3) previous years, with no more than one (1) outage during the three (3) previous year period exceeding eight (8) hours. Power loss for at least thirty (30) minutes qualifies as an outage. (7-1-26)
c. Emergency pumping capability must be accomplished by either connection of the station to at least two (2) independent utility substations as determined by and stated in a letter from the appropriate power provider, by provision of portable or in-place internal combustion engine equipment which will generate electrical or mechanical energy, or by the provision of portable pumping equipment. Such emergency standby systems must have sufficient capacity to start up and maintain the total rated running capacity of the station. Regardless of the type of emergency standby system provided, a portable pump connection to the force main with rapid connection capabilities and appropriate valving must be provided outside the dry well and wet well. (7-1-26)
i. The following general requirements apply to all internal combustion engines used to drive auxiliary pumps, service pumps through special drives, or electrical power generating equipment. (7-1-26)
(1) The engine must be protected from operating conditions that would result in damage to equipment. Unless continuous manual supervision is planned, protective equipment must be capable of shutting down the engine and activating an alarm on site and as provided in Subsection 440.06. Protective equipment must monitor for conditions of low oil pressure and overheating, except that oil pressure monitoring is not required for engines with splash lubrication. (7-1-26)
(2) The engine must have adequate rated power to start and continuously operate under all connected loads. (7-1-26)
(3) Reliability and ease of starting, especially during cold weather conditions, must be addressed in the selection of the type of fuel. (7-1-26)
(4) Fuel storage and piping facilities if provided must be constructed in accordance with applicable state and federal regulations. (7-1-26)
(5) The engine must have adequate ventilation of fuel vapors and exhaust gases. (7-1-26)
(6) All emergency equipment must be provided with instructions indicating the need for regular
starting and running of such units at full loads. (7-1-26)
(7) Emergency equipment must be protected from damage at the restoration of regular electrical power. (7-1-26)
ii. Where permanently-installed or portable engine-driven pumps are used, the following requirements in addition to the provisions of Subsection 440.07.c.i. apply. (7-1-26)
(1) Engine-driven pumps must meet the design pumping requirements unless storage capacity is available for flows in excess of pump capacity. Pumps must be designed for anticipated operating conditions, including suction lift if applicable. (7-1-26)
(2) The engine and pump must be equipped to provide automatic start-up and operation of pumping equipment unless manual start-up and operation is justified. Provisions must also be made for manual start-up. Where manual start-up and operation is justified, storage capacity and alarm system must meet the provisions of Subsection 440.07.c.ii.(3). (7-1-26)
(3) Where part or all engine-driven pumping equipment is portable, adequate emergency storage capacity as defined in Section 010 with alarm system must be provided to allow time for detection of pump station failure and transportation and hookup of the portable equipment. (7-1-26)
iii. Where permanently-installed or portable engine-driven power generating equipment is used, the following requirements apply in addition to the provisions of Subsection 440.07.c.i. (7-1-26)
(1) Power generating unit size must be adequate to provide power for pump motor starting current and for lighting, ventilation, and other auxiliary equipment necessary for safety and proper operation of the pumping station. (7-1-26)
(2) The operation of only one pump during periods of auxiliary power supply must be justified based on the design peak hourly flows relative to single-pump capacity, anticipated length of power outage, and storage capacity. (7-1-26)
(3) Manual or special sequencing controls must be provided to start pump motors unless the power generating equipment has capacity to start all pumps simultaneously with auxiliary equipment operating. (7-1-26)
(4) Provisions must be made for automatic and manual startup and load transfer unless only manual start-up and operation is justified. Automatic transfer switches must be UL listed and meet NEC requirements. The generator must be protected from operating conditions that would result in damage to equipment. Provisions must be made to allow the engine to start and stabilize at operating speed before assuming the load. Where manual start-up and transfer is justified, the storage capacity and alarm system must meet the provisions of Subsection 440.07.c.iii.(5). (7-1-26)
(5) Where portable power generating equipment and manual transfer is provided, adequate emergency storage capacity as defined in Section 010 with alarm system must be provided to allow time for detection of pump station failure and transportation and connection of power generating equipment. Special electrical connections and double throw switches must be provided for connecting portable power generating equipment. Manual transfer switches must be UL listed and meet NEC requirements. (7-1-26)
iv. Where independent power substations are used for emergency power, each separate substation and its associated transmission lines must be capable of starting and operating the pump station at its rated capacity. (7-1-26)
a. An operation and maintenance manual must be submitted to and approved by the Department as required by Section 425. Adherence to the terms of this approved manual is required. The owner is responsible for maintaining the pump station in a manner that ensures its designed operation. (7-1-26)
b. For new privately owned municipal wastewater collection pump stations, documents that detail the technical, managerial, and financial capabilities of the private entity to properly operate and maintain said pump station for the long term must be submitted to the Department in accordance with Section 409. (7-1-26)
a. A cleansing velocity of at least two (2) feet per second must be maintained within force mains at the design pumping rates. (7-1-26)
b. An air relief valve must be placed at high points in the force main to prevent air locking unless otherwise approved by the Department. The force main configuration and head conditions must be evaluated to determine the need for and placement of vacuum relief valves. (7-1-26)
c. The force mains from other than individual grinder pump stations must enter a receiving manhole. Corrosion protection for the receiving manhole must be provided. Control of odors at such discharge points must be evaluated. (7-1-26)
d. Pipe and joints must be equal to water main strength materials suitable for design conditions. The force main, reaction blocking, thrust restraint, and station piping must be designed to withstand water hammer pressures and associated cyclic reversal of stresses that are expected with the cycling of wastewater pumping stations. If necessary, the use of surge valves, surge tanks, or other suitable means to protect the force main against severe pressure changes must be evaluated. (7-1-26)
e. Force main construction near streams or water works structures and at water main crossings must meet applicable provisions of Section 430. (7-1-26)
f. Design friction losses must be in accordance with an approved PER pursuant to Section 411.03.c. (7-1-26)
g. Where force mains are constructed of material which might cause the force main to be confused with potable water mains, the force main must be appropriately identified using trench tape saying, “raw sewage,” “biohazard,” or other appropriate wording. (7-1-26)
h. Leakage tests must be specified including testing methods and leakage limits. Testing must conform with Sections 401.3.6 and 505.3.3 of the “Idaho Standards for Public Works Construction,” incorporated by reference in Section 004. (7-1-26)
i. Thrust blocking or restraint must conform with Sections 401.3.4 of the “Idaho Standards for Public Works Construction,” incorporated by reference in Section 004, or specific calculations reviewed and approved by the Department. (7-1-26)
j. Isolation valves must be used if force mains connect into a common force main. (7-1-26)
k. Force mains must be covered with sufficient earth or other insulation to prevent freezing or other physical damage. (7-1-26)
01. General. Section 441 regulates individual service connection pump stations including individual grinder pump stations and individual septic tank effluent pump stations. Certain individual service connection wastewater pumping stations may be under the jurisdiction of the Idaho Division of Occupational and Professional Licensing. (7-1-26)
a. Wastewater pumping station structures and electrical and mechanical equipment must be protected from physical damage by the one hundred (100) year flood. Wastewater pumping stations must remain fully
operational and accessible during the twenty-five (25) year flood. Local, state and federal flood plain regulations must be considered. (7-1-26)
b. The pumping station must be accessible by maintenance vehicles during all weather conditions. (7-1-26)
02. Design. Design of wastewater pumping stations must meet the applicable requirements of Subsections 441.02.a. through 441.02.c. (7-1-26)
a. Duplex pumps for individual service connection wastewater pump stations are not required. However, for developments having five (5) or more similar facilities, one (1) working spare pump for each size will be readily available at all times. (7-1-26)
i. Pumps handling raw wastewater will be capable of passing spheres of at least three (3) inches in diameter or be a grinder pump. (7-1-26)
i. The pump will be placed so that, under normal operating conditions, it will operate under a positive suction head. (7-1-26)
b. Water level control sensing devices will be designed to allow for automatic control of pumps. (7-1-26)
c. Suitable means to facilitate pump removal and to prevent backflow shall be provided. All shutoff and check valves will be accessible for maintenance. (7-1-26)
03. Submersible Pump Stations - Special Considerations. (3-31-22)
a. Submersible pumps and motors must be designed specifically for wastewater, including totally submerged operation during a portion of each pumping cycle. An effective method to detect shaft seal failure or potential seal failure must be provided. (7-1-26)
b. Submersible pumps must be readily removable and replaceable without personnel entering or dewatering the wet well, or disconnecting any piping in the wet well. (7-1-26)
c. Electrical equipment must comply with local and state codes. (7-1-26)
i. Electrical supply, control, and alarm circuits must be designed to provide strain relief and to allow disconnection from outside the wet well. Terminals and connectors must be protected from corrosion by location outside the wet well or through use of watertight seals. (7-1-26)
ii. The motor control center must be outside the wet well, readily accessible, and be protected by a conduit seal or other appropriate measures to prevent the atmosphere of the wet well from gaining access to the control center. The seal must be located so that the motor may be removed and electrically disconnected without disturbing the seal. (7-1-26)
iii. Pump motor power cords must be designed for flexibility and serviceability under conditions of extra hard usage. Ground fault interruption protection must be used to de-energize the circuit in the event of any failure in the electrical integrity of the cable. Power cord terminal fittings must be corrosion-resistant and constructed in a manner to prevent the entry of moisture into the cable, provided with strain relief appurtenances, and designed to facilitate field connecting. (7-1-26)
04. Alarm Systems. Audio-visual alarm systems with a backup power source must be provided for pumping stations. The alarm must be activated in cases of wet well high water levels and visible from the outside of the structure. (7-1-26)
05. Emergency Operation. The pumping station must be sized to allow for one (1) day's flow between the high water alarm and the building service invert or the pressure discharge pipe, whichever is closer to the
high water alarm.
(3-31-22)
06. Operation and Maintenance. An operation and maintenance manual must be submitted to and approved by the Department as required by Section 425. Adherence to the terms of this approved manual is required. The owner of the individual service connection wastewater pumping station is responsible for maintaining the pumping station in a manner that assures its designed operation. The owner of the wastewater pumping station must be supplied with a complete set of operational instructions, including emergency procedures, maintenance schedules, tools, and such spare parts as may be necessary. (7-1-26)
(3-31-22)
a. A cleansing velocity of at least two (2) feet per second must be maintained within force mains at the design pumping rates. If the force main conveys effluent from a septic tank effluent pump system, a cleansing velocity of at least one (1) feet per second must be maintained at the design pumping rates. (7-1-26)
b. Force main construction near streams or water works structures and at water pipeline crossings must meet applicable provisions of Section 430. (7-1-26)
c. Design friction losses must be in accordance with an approved PER pursuant to Section 411.03.c. (7-1-26)
d. Where force mains are constructed of material which might cause the force main to be confused with potable pipeline, the force main must be appropriately identified using trench tape saying, “raw sewage,” “biohazard,” or other appropriate wording. (7-1-26)
e. Leakage tests must be specified including testing methods and leakage limits and conform with Sections 401.3.6 and 505.3.3 of the “Idaho Standards for Public Works Construction,” incorporated by reference in Section 004. (7-1-26)
f. Thrust blocking must conform with Sections 401.3.4 of the “Idaho Standards for Public Works Construction,” incorporated by reference in Section 004. (7-1-26)
g. Isolation valves must be used if force mains connect into a common force main. (7-1-26)
h. Force mains must be covered with sufficient earth or other insulation to prevent freezing or other physical damage. (7-1-26)
(3-31-22)
a. The PER and facility plan must include a detailed discussion for new facilities regarding site selection criteria and alternatives considered. See Sections 410 and 411. (7-1-26)
b. The treatment plant structures, electrical, and mechanical equipment must be protected from physical damage by the one hundred (100) year flood. Treatment plants must be designed to remain fully operational and accessible during the one hundred (100) year flood. This requirement applies to new construction and to existing facilities undergoing material modification. Local, state, and federal flood plain regulations must be considered. (7-1-26)
c. Facilities open to the atmosphere such as wastewater lagoons, open clarifiers, open aeration basins, and other such facilities must be placed a minimum of two hundred (200) feet from residential property lines. For totally enclosed facilities with noise and odor controls, the minimum setback must be fifty (50) feet. A lesser setback may be considered by the Department on a case by case basis when considering factors including, but not limited to,
anticipated land use, property zoning, quality of wastewater, or anticipated odors. Neighboring property owners may grant long term easements or other types of legal documents tied to the land to allow for similar setbacks from future development or public use. (7-1-26)
02. Quality of Effluent. The degree of wastewater treatment must be based on the effluent requirements established by the responsible state or federal agency. Combined sewer overflows are not allowed. (7-1-26)
03. Design. (3-31-22)
a. The PER or facility plan must include a detailed discussion regarding criteria and alternatives considered in selecting the appropriate treatment type. See Sections 410 and 411. The plant design must provide the necessary flexibility to perform satisfactorily within the expected range of waste characteristics and volumes. (7-1-26)
b. Department policy is to encourage the development of any valid methods or equipment for treatment of wastewater. The lack of inclusion in these standards of some types of wastewater treatment processes or equipment should not be construed as precluding their use. The Department may approve other types of wastewater treatment processes and equipment that meet the performance standards set forth in these rules under the condition that the operational reliability and effectiveness of the process or device must have been demonstrated under similar conditions with a suitably-sized unit operating at its design load conditions, to the extent required. To determine that such new processes and equipment or applications have a reasonable and substantial chance of success, the Department may require the following: (7-1-26)
i. Monitoring observations, including test results and engineering evaluations, demonstrating the efficiency of such processes. (3-31-22)
ii. Detailed description of the test methods. (3-31-22)
iii. Testing, including appropriately composited samples, under various ranges of strength and flow rates (including diurnal variations) and waste temperatures over a sufficient length of time to demonstrate performance under climatic and other conditions which may be encountered in the area of the proposed installations. (7-1-26)
iv. Appropriate testing be conducted and evaluations be made under the supervision of a competent process engineer other than those employed by the manufacturer or developer. (7-1-26)
c. The design period must be clearly identified in the PER or facility plan described in Sections 410 and 411. (7-1-26)
d. Hydraulic design flow conditions critical to the design of the treatment plant must be as described in the PER required by Section 411. (7-1-26)
i. Initial low flow conditions must be evaluated in the design to minimize operational problems with freezing, septicity, flow measurements and solids dropout. The appropriate design flows must be considered in evaluating unit processes, pumping, piping, etc. (7-1-26)
ii. The treatment plant design capacity must be as described in the PER as required by Section 411. The plant design flow selected must meet the appropriate effluent and water quality standards that are set forth in the discharge or other appropriate permit. For plants subject to high wet weather flows or overflow detention pump-back flows, the design maximum flows that the plant is to treat on a sustained basis must be specified. (7-1-26)
iii. Facilities for the equalization of flows and organic shock load must be considered at all plants which are critically affected by surge loadings. (7-1-26)
e. Organic loadings for wastewater treatment plant design must be based on the information provided in the PER described in Section 411. The effects of septage flow which may be accepted at the treatment facility must
be given consideration and appropriate facilities must be included in the design. See Section 520. (7-1-26)
f. The shock effects of high concentrations and diurnal peaks for short periods of time on the treatment process, particularly for small treatment plants, must be considered. (7-1-26)
g. All piping and channels must be designed to carry the maximum expected flows. Conduits must be designed to avoid creation of pockets and corners where solids can accumulate. (7-1-26)
h. Suitable gates or valves must be placed in channels to seal off unused sections which might accumulate solids. The use of shear gates, stop plates or stop planks is permitted where they can be used in place of gate valves or sluice gates. Non-corrodible materials must be used for control gates and conduits. (7-1-26)
i. Component parts of the plant must be arranged for appropriate operating and maintenance convenience, flexibility, economy, continuity of maximum effluent quality, and ease of installation of future units. (7-1-26)
j. Flow division control facilities must be provided as necessary to ensure organic and hydraulic loading control to plant process units and must be designed for easy operator access, change, observation, and maintenance. Appropriate flow measurement facilities must be incorporated into the flow division control design. (7-1-26)
k. An odor management plan must be submitted to and approved by the Department as a part of the PER described in Section 411. The Water Environment Federation Guidance referenced in Section 008 provides guidance for use in developing an odor management plan that is inclusive of the facilities being designed. (7-1-26)
l. Facilities must be designed with regard for proper operation and maintenance and protection during cold weather temperatures expected at the specific location. The Water Environment Federation Guidance referenced in Section 008 provides guidance for use in designing, operating and maintaining facilities in cold weather. (7-1-26)
i. Properly located and arranged bypass structures and piping must be provided so that each unit of the plant can be removed from service independently. The bypass design must facilitate plant operation during unit maintenance and emergency repair to minimize deterioration of effluent quality and ensure rapid process recovery upon return to normal operational mode. The actuation of all bypasses requires manual action by operating personnel. All power-actuated bypasses must be designed to permit manual operation in the event of power failure. (7-1-26)
ii. Unit bypassing during construction must be in accordance with the PER described in Section 411. (7-1-26)
b. Drains or sumps must be provided to completely dewater each unit to an appropriate point in the process. Due consideration must be given to the possible need for hydrostatic pressure relief devices to prevent flotation of structures. Pipes subject to plugging must be provided with means for mechanical cleaning or flushing. (7-1-26)
c. Materials must be selected that are appropriate under conditions of exposure to hydrogen sulfide and other corrosive gases, greases, oils, and other constituents frequently present in wastewater. This is particularly important in the selection of metals and paints. (7-1-26)
d. The contents and direction of flow must be identified on the piping in a contrasting color. (7-1-26)
e. Tools, accessories, and spare parts necessary for the plant operator’s use must be provided. (7-1-26)
f. Readily accessible storage and workspace facilities must be provided, and consideration must be
given to provision of a garage for large equipment storage, maintenance, and repair. (7-1-26)
g. Effective site erosion control must be provided during construction. (7-1-26)
h. Upon completion of the plant, the ground must be graded and landscaped in accordance with the PER described in Section 411. (7-1-26)
a. The outfall must be designed to discharge to the receiving water in a manner acceptable to various reviewing authorities including, but not limited to, EPA, the Department, U.S. Army Corp of Engineers, Idaho Department of Water Resources, and local jurisdictions. (7-1-26)
b. The outfall must be so constructed and protected against the effects of floodwater, ice, or other hazards as to reasonably ensure its structural stability and freedom from stoppage. Hazards to navigation must be considered in designing outfalls. (7-1-26)
c. All outfalls must be designed so that a sample of the effluent can be obtained at a point after the final treatment process and before discharge to or mixing with the receiving waters. (7-1-26)
a. All wastewater treatment plants must be provided with an alternate source of electric power or pumping capability to allow continuity of operation during power failures. Refer to Subsection 440.07.c. for design requirements. Methods of providing alternate sources include: (7-1-26)
i. The connection of at least two (2) independent power sources such as substations. A power line from each substation is required if this method is used. The determination of the independent power sources must be done by the appropriate power provider and stated in a letter from that provider. (7-1-26)
ii. In-place internal combustion engine equipment which will generate electrical or mechanical energy. (3-31-22)
iii. Portable pumping equipment when only emergency pumping is required. Where part or all of the engine-driven pumping equipment is portable, adequate emergency storage capacity with alarm system must be provided to allow time for detection of pump station failure and transportation and hookup of the portable equipment. (7-1-26)
iv. Standby power-generating capacity normally is not required for aeration equipment used in the activated sludge process. In cases where a history of chronic, long-term (four (4) hours or more) power outages have occurred, auxiliary power for minimum aeration of the activated sludge is required as provided in Subsections 450.06.a.i. and 450.06.a.ii. (7-1-26)
v. Standby power-generating capacity, as provided in Subsections 450.06.a.i. and 450.06.a.ii., is required for disinfection facilities and dechlorination facilities. (7-1-26)
b. Stairways must be installed in lieu of ladders for top access to units requiring routine inspection and maintenance (such as digesters, trickling filters, aeration tanks, clarifiers, tertiary filters, etc.). (7-1-26)
c. Flow measurement devices must be provided to measure the plant influent or effluent flow. If influent flow is significantly different from effluent flow, both must be measured or otherwise accounted for by other flow measurement facilities. (7-1-26)
i. Other flow measurement must be provided if required by provisions of the discharge permit or as required for plant operational control such as return activated sludge, waste activated sludge, and recycled flow. (7-1-26)
ii. Indicating, totalizing, and recording flow measurement devices for all influent or effluent flows must be provided for all plants. Any other flow measurement device may be indicating and totalizing only. All flow measurement equipment must be sized to function to a satisfactory level of accuracy over the full range of flows expected and must be protected against freezing. (7-1-26) iii. Flow measurement equipment including approach and discharge conduit configuration and critical control elevations must be designed to ensure the required hydraulic conditions necessary for the measurement accuracy needed for the specific application. (7-1-26) iv. The flow measurement devices must be calibrated and certified at manufacturer-specified frequencies. (7-1-26) d. Effluent composite sampling equipment must be provided at all mechanical plants and at other facilities where necessary to meet discharge permit monitoring requirements. Composite sampling equipment must also be provided as needed for influent sampling and for monitoring plant operations. The influent sampling point must be located prior to any process return flows. (7-1-26)
(3-31-22)
a. Provisions must be made to consider the protection of maintenance personnel and visitors from typical and foreseeable hazards in accordance with the engineering standards of care. Enclosure of the plant site with a fence and signs designed to discourage the entrance of unauthorized persons and animals is required. (7-1-26) b. The materials utilized for storage, piping, valves, pumping, metering, splash guards, etc., must be specially selected considering the physical and chemical characteristics of each hazardous or corrosive chemical. (7-1-26)
(3-31-22)
a. All treatment plants must include a laboratory for making the necessary analytical determinations and operating control tests, except for those plants utilizing only processes not requiring laboratory testing for plant control and where satisfactory off-site laboratory provisions are made to meet the permit monitoring requirements. The laboratory must have sufficient size, bench space, equipment, and supplies to perform all self-monitoring analytical work required by disposal permits, and to perform the process control tests necessary for good management of each treatment process included in the design. (7-1-26) b. Expected minimum laboratory needs must be addressed in the PER pursuant to Section 411. Treatment plant laboratory needs are divided into the following three (3) general categories: (7-1-26) i. Plants performing only basic operational testing; this typically includes pH, temperature, dissolved oxygen, and chlorine residual. (3-31-22) ii. Plants performing more complex operational and permit laboratory tests including biochemical oxygen demand, suspended solids, and fecal coliform analysis. (3-31-22) iii. Plants performing more complex operational, permit, industrial pretreatment, and multiple plant laboratory testing. (3-31-22)
09. Operation and Maintenance. An operation and maintenance manual must be submitted to and approved by the Department as required by Section 425. Adherence to the terms of this approved manual is required. The owner is responsible for maintaining the wastewater treatment facility in a manner that ensures its designed operation. (7-1-26)
01. Scope. Section 455 includes requirements in addition to Section 450 requirements for approval of private wastewater treatment plants. Individual extended treatment package systems for on-site systems are regulated by IDAPA 58.01.03, “Individual/Subsurface Sewage Disposal Rules and Rules for Cleaning of Septic Tanks.” (7-1-26)
a. If the Department determines that a proposed private wastewater treatment plant is reasonably accessible to a wastewater system, the use of the private wastewater treatment plant may be denied. (7-1-26)
b. A compliance agreement schedule authorized by Section 39-116A, Idaho Code, is required for each private wastewater treatment plant approved unless specifically waived by the Department in writing. If a private wastewater treatment plant installation is only a temporary or interim measure in a long-term plan, a compliance agreement schedule will include a sunset clause with a date for the private wastewater treatment plant to cease operation and will require the plant owner to fund and construct the eventual hookup to the municipal wastewater collection system when the system becomes reasonably accessible. The compliance agreement schedule will address such things as operation and maintenance requirements and monitoring, reporting requirements, and other project-specific items as applicable. The owner is responsible for complying with the requirements of the compliance agreement schedule. The compliance agreement schedule will be renewed every five (5) years; when ownership of the treatment plant changes; or at the request of the owners or Department, so long as the system is in operation. (7-1-26)
c. Private wastewater treatment plants must be designed to provide service within the contiguous area including all adjacent and connected parcels or subdivisions that are part of the same overall planned development footprint and provide service to future phases of the planned development. The design capacity must account for buildout conditions or provide for means to readily expand capacity to accommodate future growth. Anticipated phases of development and future growth must be accounted for within the facility plan and PER. (7-1-26)
d. The minimum size of a private wastewater treatment plant allowed under these rules is twenty-five thousand (25,000) gallons per day design capacity based on average day flows. (7-1-26)
i. The minimum size requirements do not apply to proposed systems with suitably configured passive wastewater treatment technologies including, but not limited to, facultative lagoons, free water surface wetlands, and vegetated submerged beds. (7-1-26)
ii. The Department may approve private wastewater treatment plants smaller than twenty-five thousand (25,000) gallons per day design capacity, based on average day flows, provided the treatment plant will be maintained under original ownership. (7-1-26)
e. Prior to transfer of ownership of a private wastewater treatment plant to another entity, the proposed new owner must submit adequate documentation demonstrating sufficient technical, financial, and managerial capacity, as described in Section 409. (7-1-26)
02. Facility Plan and PER. The facility plan and PER for private wastewater treatment plants must include project-specific estimated permit effluent limits and requirements based on discussion with the applicable permitting agency, the information listed in this subsection, and information specified in Sections 410 and 411. (7-1-26)
a. The private wastewater treatment plant will have at least two (2) full years of operating data on five (5) separate installations in the United States. The data submittal will include the name, address, and telephone number for a regulatory agency contact person or an owner or operator familiar with the performance of each reported installation. (7-1-26)
b. The private wastewater treatment plant will be a dual train type (or equivalent/greater) with redundant pumps and blowers from influent works to the disposal site and provide sufficient redundancy to continue processing incoming wastewater at peak flows while any one (1) component or process is out of service. Standby or emergency power will be provided to fully operate the wastewater treatment plant during a power outage unless the water system would also be out during a power outage. (7-1-26)
a. Plans and specifications for the private wastewater treatment plants will not be approved until the owner is in receipt of one of the following (whichever is applicable): (7-1-26)
i. A draft discharge permit for proposed surface water discharges; (7-1-26)
ii. A draft reuse permit from the Department in accordance with IDAPA 58.01.17, “Recycled Water Rules”; (7-1-26)
iii. Water balance calculations showing a net water loss for total containment lagoons included in approved PER; or (7-1-26)
iv. A subsurface installation permit application submitted to the local public health district and a completed site evaluation or nutrient pathogen evaluation in accordance with Section 260. (7-1-26)
b. A signed contract or other documentation acceptable to the Department that provides for ultimate legal disposal or use of the sludge must be submitted to the Department prior to plan and specification approval. (7-1-26)
a. Screening, coarse or fine, or comminutors are required for all mechanical plants and will be addressed for other types of plants. These facilities must be designed for peak hourly flow. Multiple channels must be provided and equipped with the necessary gates to isolate flow from any screening unit. Provisions must also be made to facilitate dewatering each unit. The channel preceding and following the screen must be shaped to minimize settling of solids. (7-1-26)
b. For mechanical plants with design flow less than one million gallons per day (1 mgd), and where a single mechanically cleaned screen is used, an auxiliary manually cleaned screen must be provided. Where two (2) or more mechanically cleaned screens are used, the design must provide for taking any unit out of service without sacrificing the capability to screen the design peak instantaneous flows. (7-1-26)
02. Grit Removal Facilities. Grit removal and handling facilities must be provided for all mechanical wastewater treatment plants. Consideration must be given to possible damaging effects on pumps, comminutors, and other preceding equipment, and the need for additional storage capacity in treatment units where grit is likely to accumulate. (7-1-26)
01. Settling Units. A minimum of two (2) settling units capable of independent operation must be provided in all plants where design flow exceeds one hundred thousand (100,000) gallons/day. Plants not having multiple units must include other provisions to assure continuity of treatment. (7-1-26)
02. Sizing. Sizing must be calculated for both average day flow and peak hour flow conditions, and the larger surface area determined must be used. (7-1-26)
03. Isolation. The plant design must allow for isolation of each unit and allow for sludge and scum removal. (7-1-26)
04. Baffling. Baffling must be designed to control solids carry-over. (7-1-26)
05. Minimum Side Depth. The minimum side depth for primary settling facilities must be ten (10) feet. The minimum side depth for secondary settling facilities must be twelve (12) feet. (7-1-26)
471. -- 479. (RESERVED)
01. Facilities. Facilities for processing sludge must be provided for all mechanical wastewater treatment plants. Facilities must be capable of processing sludge to a form suitable for ultimate disposal. Final disposal or utilization must be in accordance with applicable federal and state regulations. (7-1-26)
02. Design. Sludge processing, storage and disposal facility design must comply with the PER. (7-1-26)
03. Multiple Units. Multiple units capable of independent operation must be provided in plants where design average flows exceed one hundred thousand (100,000) gallons/day. Plants not having multiple units must include other provisions to assure continuity of treatment. The plant design must allow for isolation of each unit. (7-1-26)
481. -- 489. (RESERVED)
If biological treatment is used, the process must be determined in the PER. The choice must be based on influent characteristics and effluent requirements. (7-1-26)
01. Trickling Filters. (3-31-22)
a. Trickling filters must be preceded by effective settling tanks equipped with scum and grease collecting devices or other suitable pretreatment facilities. (7-1-26)
b. The flow must be uniformly distributed across the surface of the media. The piping system, including dosing equipment and distributor, must be designed to provide capacity for the design peak hour flow, including recirculation. (7-1-26)
c. Media. (3-31-22)
i. Trickling filter media must be appropriate for the wastewater and of sufficient strength to support itself under design loading and build up of biomass. (7-1-26)
ii. The media must have a minimum depth of six (6) feet above the underdrains. (7-1-26)
d. Underdrainage System. (3-31-22)
i. Underdrains must be provided and the underdrainage system must cover the entire floor of the filter. Inlet openings into the underdrains must have an unsubmerged gross combined area equal to at least fifteen (15) percent of the surface area of the filter. (7-1-26)
ii. The underdrainage system, effluent channels, and effluent pipe must be designed to permit free passage of air. (7-1-26)
e. Special Features. (3-31-22)
i. All distribution devices, underdrains, channels, and pipes must be installed so that they may be properly maintained, flushed or drained. (7-1-26)
ii. Covers must be provided to maintain operation and treatment efficiencies when climatic conditions are expected to result in problems due to cold temperatures. (7-1-26)
iii. The piping system must be designed for recirculation as needed to achieve the design efficiency. The recirculation rate must be variable and subject to plant operator control at the range of 0.5:1 up to 4:1 (ratio of recirculation rate versus design flow). A minimum of two (2) recirculation pumps must be provided. (7-1-26)
f. Mercury rotary distributor seals are not permitted. (7-1-26)
g. Volumes of filter media must be based upon pilot testing with the particular wastewater or any of the various empirical design equations that have been verified through actual full scale experience. Such calculations must be submitted to the Department if pilot testing is not utilized. Trickling filter sizing design must consider peak organic load conditions including the oxygen demands due to solids and process recycle flows. (7-1-26)
a. Aeration. (3-31-22)
i. The size of the aeration tank for any particular adaptation of the process must be determined by full scale experience, pilot plant studies, or standard calculations based on solids retention time, food to microorganism ratio, and mixed liquor suspended solids levels. Other factors, such as size of treatment plant, diurnal load variations, and degree of treatment required, must also be considered. In addition, temperature, alkalinity, pH, and reactor dissolved oxygen must be considered when designing for nitrification. Calculations must be submitted to the Department in the PER to justify the basis for design of aeration tank capacity. (7-1-26)
ii. Arrangement of Aeration Tanks. (3-31-22)
(1) The dimensions of each aeration tank or return sludge reaeration tank must be able to maintain effective mixing and utilization of air. Horizontally mixed aeration tanks must have a depth of greater than five point five (5.5) feet. (7-1-26)
(2) Total aeration tank volume plus redundancy requirements must be divided among two (2) or more equal units, capable of independent operation. (7-1-26)
(3) Inlets and Outlets. (3-31-22)
(a) Inlets and outlets for each aeration tank unit must be designed to control flow to any unit with reasonable accuracy and to maintain reasonably constant liquid level. The properties of the system must permit the design peak day flow to be treated with any single aeration tank unit out of service. The properties of the system must permit the design peak hour hydraulic flow to be carried with any single aeration tank unit out of service. (7-1-26)
(b) Channels and pipes carrying liquids with solids in suspension must be designed to be self-cleansing. (7-1-26)
(c) Aeration tanks must be designed to include adequate control or removal of scum and foam. (7-1-26)
(4) All aeration tanks must have a freeboard of not less than eighteen (18) inches unless otherwise approved by the Department. (7-1-26)
iii. Aeration Equipment. (3-31-22)
(1) Oxygen requirements are based on maximum diurnal organic loading, degree of treatment, and level of suspended solids concentration to be maintained in the aeration tank mixed liquor. Aeration equipment must
be capable of maintaining a minimum of two point zero (2.0) mg/L of dissolved oxygen in the mixed liquor at all times and provide thorough mixing of the mixed liquor. For a horizontally mixed aeration tank system, an average velocity of one (1) foot per second must be maintained. In the absence of experimentally determined values, the design oxygen requirements for all activated sludge processes must be 1.1 lb O₂ per lb of design peak hour BOD₅ applied to the aeration tanks, except the extended aeration process, for which the value must be one point five (1.5) to include endogenous respiration requirements. (7-1-26)
(a) Where nitrification is required or will occur, the oxygen requirement for oxidizing ammonia must be added to the above requirement for carbonaceous BOD₅ removal and endogenous respiration requirements. The nitrogenous oxygen demand (NOD) must be four point six (4.6) times the diurnal peak hour total Kjeldahl nitrogen content of the aeration tank influent. In addition, the oxygen demands due to recycle flows must be considered due to the high concentrations of BOD₅ and total Kjeldahl nitrogen associated with such flows. (7-1-26)
(b) Aeration equipment design must meet maximum oxygen demand, maintain process performance with the largest unit out of service, and provide for varying the amount of oxygen transferred in proportion to the load demand on the plant. (7-1-26)
(2) Air requirements including, but not limited to, process air, channel aeration, aerobic digestion, and miscellaneous plant air must be submitted to the Department in the PER. Blowers must be provided in multiple units, so arranged and in such capacities as to meet the maximum air demand with the single largest unit out of service. The design must also provide for varying the volume of air delivered in proportion to the load demand of the plant. Aeration equipment must be easily adjustable in increments and maintain solids suspension within these limits. (7-1-26)
(3) Mechanical Aeration Systems. (3-31-22)
(a) The mechanism and drive unit must be designed for the expected conditions in the aeration tank in terms of the power performance. Certified testing must be provided to verify mechanical aerator performance. Refer to applicable provisions of Subsection 490.02. In the absence of specific design information, the oxygen requirements must be calculated for mechanical aeration systems using a transfer rate not to exceed two (2) pounds of oxygen per horsepower per hour in clean water under standard test conditions. Design transfer efficiencies must be included in the specifications. (7-1-26)
(b) Motors, gear housing, bearings, grease fittings, and other mechanical units, must be easily accessible and protected from inundation and spray as necessary for proper functioning of the unit. (7-1-26)
(c) Where extended cold weather conditions occur, the aerator mechanism and associated structure must be protected from freezing due to splashing. Due to high heat loss, subsequent treatment units must be protected from freezing. (7-1-26)
b. Non-aerated tanks or zones within aeration tanks must have mixing equipment adequate to fully mix the contents. Calculations must be provided in the PER for sizing this equipment. (7-1-26)
c. Return Sludge Equipment. (3-31-22)
i. The rate of sludge return must be varied by adjustable weirs or variable speed pumps to pump sludge. For very small wastewater systems, timers may be used for sludge return. The return sludge rate of withdrawal from the final settling tank is a function of the concentration of suspended solids in the mixed liquor entering it, the sludge volume index of these solids, and the length of time these solids are retained in the settling tank. (7-1-26)
ii. If a consolidated return sludge pump facility is used, the maximum return sludge capacity must be obtained with the largest pump out of service. If individual sludge pumps are used at each settling basin, the pumps must be designed to facilitate their rapid removal and replacement with a standby unit stored at the treatment plant site. If air lifts are used for returning sludge from each settling tank hopper, no standby unit is required provided the design of the air lifts facilitate their rapid and easy cleaning and provided other suitable standby measures are made available. Air lifts must be at least three (3) inches in diameter unless otherwise approved by the Department.
(7-1-26)
iii. Discharge piping must be at least four (4) inches in diameter and must be designed to maintain a velocity of not less than two (2) feet per second when return sludge facilities are operating at normal return sludge rates. Suitable devices for observing, sampling, and controlling return activated sludge flow from each settling tank hopper must be provided. (7-1-26)
iv. Means for observing, measuring, sampling, and controlling waste activated sludge flow must be provided. (7-1-26)
d. Sequencing Batch Reactors. (7-1-26)
i. The fill and draw mode of the activated sludge process commonly termed the Sequencing Batch Reactor may be used in Idaho. The design must be based on experience at other facilities and meet the applicable provisions under Sections 450, 470 and 490, except as modified in Subsections 490.02.d.ii. through 490.02.d.xii. Continuity and reliability of treatment equal to that of the continuous flow through modes of the activated sludge process must be provided. (7-1-26)
ii. At least two (2) tanks must be provided. (7-1-26)
iii. The decantable volume and capacity of the sequencing batch reactor system with the largest basin out of service must be sized to pass at least seventy-five (75) percent of the design maximum day flow without changing cycle times. A decantable volume of at least four (4) hours with the largest basin out of service based on one hundred (100) percent of the design maximum day flow is permissible. (7-1-26)
iv. System reliability with any single tank unit out of service and the instantaneous delivery of flow must be evaluated in the design of decanter weirs and approach velocities. (7-1-26)
v. Reactor design must provide for scum removal and prevent overflow of settled solids. (7-1-26)
vi. An adequate zone of separation between the sludge blanket and the decanters must be maintained throughout the decant phase. Decanters which draw the treated effluent from near the water surface throughout the decant phase are recommended. (7-1-26)
vii. Solids management to accommodate basin dewatering must be considered. (7-1-26)
viii. The blowers must be provided in multiple units, so arranged and in such capacities as to meet the maximum air demand in the oxic portions of the fill/react and react phases of the cycle with the single largest unit out of service. (7-1-26)
ix. Mechanical mixing independent of aeration must be provided for all systems where biological phosphorus removal or denitrification is required. (7-1-26)
x. All twenty-four (24) hour effluent quality composite samples for compliance reporting or monitoring plant operations must be flow-paced and include samples collected at the beginning and end of each decant phase. (7-1-26)
xi. A programmable logic controller (PLC) must be provided. Multiple PLCs must be provided as necessary to assure rapid process recovery or minimize the deterioration of effluent quality from the failure of a single controller. An uninterruptible power supply with electrical surge protection must be provided for each PLC to retain program memory (i.e., process control program, last-known set points and measured process/equipment status, etc.) through a power loss. A hard-wired backup for manual override must be provided in addition to automatic process control. Both automatic and manual controls must allow independent operation of each tank. In addition, a fail-safe control allowing at least twenty (20) minutes of settling between the react and decant phases must be provided. The fail-safe control must not be adjusted by the operator. (7-1-26)
xii. A sufficient quantity of spare parts must be on hand and consideration given to parts with a low
mean time between failure such as electrical relays and solid state electronics. (7-1-26)
a. Biological treatment processes not included in these rules must be in accordance with Subsection 450.03. (7-1-26)
b. Details for Membrane Bioreactor (MBR) plants must be submitted and approved in the PER. In addition to the provisions of Section 411, details must include plant layout, calculations for hydraulic capacity and air required, membrane technology considered and membrane type and model selected, results from similar type MBR plants already in operation, and anticipated sludge production. (7-1-26)
a. These rules pertain to all new, and existing material modified, municipal wastewater lagoons, including discharging or total containment lagoons, municipal wastewater treatment lagoons, municipal wastewater or recycled water storage lagoons, and any other municipal wastewater lagoons not regulated under IDAPA 58.01.03, 'Individual/Subsurface Sewage Disposal Rules and Rules for Cleaning of Septic Tanks,' that have the potential to degrade waters. Lagoons are also sometimes referred to as ponds. Section 493 does not apply to industrial lagoons or mining tailings ponds, single-family dwellings utilizing a single lagoon, two (2) cell infiltrative system, those animal waste lagoons excluded from review under Section 39-118, Idaho Code, or storm water ponds. (7-1-26)
b. Lagoons utilized for equalization and sludge storage do not have to meet the requirements of Subsections 493.06 through 493.08, but must comply with all other applicable subsections. (7-1-26)
a. All lagoons covered under this section must be seepage tested at an interval of at least every ten (10) years by or under the supervision of an Idaho licensed professional engineer or an Idaho licensed professional geologist. (7-1-26)
b. As part of the construction process, all new lagoons must be seepage tested by or under the supervision of an Idaho licensed professional engineer or an Idaho licensed professional geologist. (7-1-26)
c. Lagoons must be seepage tested if a change of condition to the liner occurs that may affect its permeability, including but not limited to liner repair below the high water line, liner replacement, lagoon dewatering of soil-lined lagoons which results in desiccation of the soil liner, seal installation, or earthwork affecting liner integrity. Prior to performing activities that may affect liner permeability, such as solids removal, the system owner must contact the Department in writing to determine if a seepage test will be required prior to returning the lagoon to service. (7-1-26)
d. The procedure for performing a seepage test or alternative analysis must be approved by the Department prior to conducting the test, and the test results must be submitted to the Department for review. (7-1-26)
a. Lagoons must be designed and sealed such that seepage loss through the seal is as low as possible. Seals consisting of soils, bentonite, or synthetic liners may be considered, provided the permeability, durability, and integrity of the proposed material can be satisfactorily demonstrated for anticipated conditions. (7-1-26)
b. The seepage rate for lagoons constructed after April 15, 2007, must be no more than zero point one hundred twenty-five (0.125) inches (1/8 inch) per day. The leakage rate for existing lagoons constructed prior to April
15, 2007, must be no more than zero point twenty-five (0.25) inches (1/4 inch) per day. (7-1-26)
c. For lagoons located over sensitive aquifers or with a documented direct hydraulic connection to a 303d listed stream segment, the seepage rate may be no more than zero point one hundred twenty-five (0.125) inches (one-eighth (1/8) inch) per day. (7-1-26)
04. Lagoons Leaking Above the Allowable Amount. If a lagoon is found to be leaking at a rate higher than allowed, the owner of the lagoon, in accordance with a schedule negotiated with and approved by the Director, is required to: (7-1-26)
a. Repair the leak and retest for compliance; (3-31-22)
b. Re-line the lagoon and retest for compliance with a leakage rate of no more than zero point one hundred twenty-five (0.125) inches (1/8 inch) per day regardless of the original lagoon construction date; (7-1-26)
c. Drain the lagoon in an approved manner and stop using the lagoon; or (3-31-22)
d. Determine the impact of the leaking lagoon on the environment based on groundwater sampling and modeling. The procedure for performing groundwater sampling and monitoring must be approved by the Department. Any impact must comply with IDAPA 58.01.11, “Groundwater Quality Rule,” and IDAPA 58.01.02, “Water Quality Standards.” If the impact does not comply with IDAPA 58.01.11, and IDAPA 58.01.02, the owner of the lagoon must follow one (1) of the steps set out in Subsections 493.04.a. through 493.04.c. (7-1-26)
05. Location. (3-31-22)
a. Wastewater lagoons must be placed in accordance with the provisions in Subsection 450.01.c. In all cases, the design location must consider odors, nuisances, etc. This distance is to the toe of the exterior slope of the dike or to the top of the cut for a lagoon placed into a hillside. More restrictive planning and zoning or other local requirements may apply. (7-1-26)
b. A minimum separation of two (2) feet between the bottom of the lagoon and the maximum groundwater elevation must be provided in the design. (7-1-26)
c. A minimum separation of two (2) feet between the lagoon bottom and any bedrock formation must be provided in the design. (7-1-26)
06. Basis of Design. (3-31-22)
a. Design variables such as climatic conditions, odor, lagoon depth, multiple units, detention time, and additional treatment units must be considered with respect to applicable standards for BOD5, total suspended solids (TSS), fecal coliform, dissolved oxygen (DO), pH, and other effluent requirements and limits. (7-1-26)
b. The PER must include all design criteria for the development of the lagoon design. (7-1-26)
c. The reaction rate coefficient for domestic wastewater which includes some industrial wastes, other wastes, and partially treated wastewater must be determined experimentally for various conditions which might be encountered in the lagoons or actual data from lagoons in similar climates. Conversion of the reaction rate coefficient at other temperatures must be made based on experimental data. (7-1-26)
d. Oxygen requirements are based on the design average BOD5 loading, the degree of treatment, and the concentration of suspended solids to be maintained. If needed for treatment objectives, aeration equipment must be designed to maintain a minimum dissolved oxygen level of two (2) mg/L in the lagoons at all times. Suitable protection from weather must be provided for electrical controls. Aerated cells must be followed by a polishing cell with a detention time of a minimum of twenty-four (24) hours. (7-1-26)
07. Industrial Wastes as a Part of the Municipal Wastewater. (3-31-22)
a. Design must account for the type and effects of industrial wastes on the treatment process. (7-1-26)
b. Industrial wastes must not be discharged to lagoons without assessment of the effects such substances may have upon the treatment process or disposal requirements in accordance with state and federal laws. (7-1-26)
08. Number of Cells. (7-1-26)
a. A wastewater treatment lagoon system must consist of a minimum of three (3) cells designed to facilitate both series and parallel operations. Two (2) cell systems may be utilized in very small installations of less than fifty thousand (50,000) gallons per day average day flow. (7-1-26)
b. All systems must be designed with piping flexibility to permit isolation of any cell without affecting the transfer and disposal capabilities of the total system. (7-1-26)
09. Lagoon Construction Details. (7-1-26)
a. Embankments and Dikes. (3-31-22)
i. Dikes must be constructed of relatively impervious soil and compacted to at least ninety-five (95) percent Standard Proctor Density to form a stable structure. Vegetation and other unsuitable materials must be removed from the area where the embankment is to be placed. (7-1-26)
ii. The minimum dike top width must be ten (10) feet to permit access for maintenance vehicles. (7-1-26)
iii. Inner and outer dike slopes must not be steeper than one (1) vertical to three (3) horizontal (1:3). (7-1-26)
iv. Inner slopes must not be flatter than one (1) vertical to four (4) horizontal (1:4). Flatter slopes can be specified for larger installations because of wave action but have the disadvantage of added shallow areas being conducive to emergent vegetation. Outer slopes must be sufficient to prevent surface runoff from entering the lagoons. (7-1-26)
v. Minimum freeboard must be three (3) feet, except for small systems of less than fifty thousand (50,000) gallons per day average day flow, two (2) feet is acceptable. (7-1-26)
vi. The minimum operating depth must be designed to prevent growth of aquatic plants and damage to the dikes, bottom, control structures, aeration equipment, and other appurtenances. Operating depth must not be less than two (2) feet. (7-1-26)
b. Lagoon Bottom. (7-1-26)
i. Soil used in constructing the lagoon bottom (not including the seal) and dike cores must be relatively incompressible and tight and compacted to at least ninety-five (95) percent Standard Proctor Density. (7-1-26)
ii. Lagoons must be sealed such that seepage loss through the seal complies with Subsection 493.03. Results of a testing program which substantiates the adequacy of the proposed seal must be incorporated into or accompany the PER. (7-1-26)
c. Miscellaneous. (3-31-22)
i. The lagoon area must be enclosed with an adequate fence to prevent livestock entering and discourage trespassing. This requirement does not apply to lagoon areas which store or impound Class A recycled water. (7-1-26)
ii. An all-weather access road must be provided to the lagoon site to allow year-round maintenance of the facility. (7-1-26)
iii. Appropriate permanent signs must be provided along the fence around the lagoon to designate the nature of the facility and advise against trespassing. At least one (1) sign must be provided on each side of the site and one (1) for every five hundred (500) feet of its perimeter. (7-1-26)
iv. Flow measurement requirements are provided in Subsection 450.06.c. Effective weather protection must be provided for the recording equipment. (7-1-26)
v. A groundwater monitoring plan must be submitted to the Department for review and approval as a part of the PER. Unless otherwise approved by the Department, a system of wells or lysimeters is required around the perimeter of the lagoon site to facilitate groundwater monitoring. (7-1-26)
10. Closure. The owner must notify the Department at least six (6) months prior to permanently removing any wastewater lagoon facility from service, including any treatment or storage lagoon. Prior to commencing closure activities, the owner must: (7-1-26)
a. Participate in a pre-closure on-site meeting with the Department; (3-31-22)
b. Develop a site closure plan that identifies specific closure, site characterization, or cleanup tasks with scheduled task completion dates in accordance with agreements made at the pre-closure on-site meeting; and (7-1-26)
c. Submit the completed site closure plan to the Department for review and approval within forty-five (45) days of the pre-closure on-site meeting. The facility must complete the Department approved site closure plan. (7-1-26)
01. General. Disinfection of treated wastewater must be provided as necessary to meet applicable standards. The design of new municipal wastewater treatment facilities, or municipal wastewater treatment facilities undergoing material modifications, must meet the bacterial standards and the disinfectant residual limit for the effluent. The disinfection process must be selected after due consideration of waste characteristics, type of treatment process provided prior to disinfection, waste flow rates, pH of waste, disinfectant demand rates, current technology application, cost of equipment and chemicals, power cost, and maintenance requirements as determined in the PER. Where a disinfection process other than chlorination, ultraviolet disinfection, or ozone is proposed, supporting data from pilot plant installations or similar full scale installations are required as a basis for the design of the system. (7-1-26)
02. Determining the Necessity for Disinfection. Disinfection at a municipal wastewater treatment facility is required when: (7-1-26)
a. Required by a surface water discharge permit; or (7-1-26)
b. The effluent is disposed to a facility required to meet the disinfection requirements in IDAPA 58.01.17, “Recycled Water Rules.” (7-1-26)
c. The effluent is disposed to a facility, where groundwater contamination has exceeded the bacterial limit in IDAPA 58.01.11, “Groundwater Quality Rule,” and it has been determined by the Department that disinfection is required. (7-1-26)
03. Chlorine Disinfection. (3-31-22)
a. Chlorine is available for disinfection in gas, liquid (hypochlorite solution), and pellet (hypochlorite tablet) form. The type of chlorine must be evaluated in the facility plan or PER. (7-1-26)
b. For disinfection, the capacity must be adequate to produce an effluent that will meet the applicable bacterial limits specified by the regulatory agency for that installation. Required disinfection capacity will vary, depending on the uses and points of application of the disinfection chemical. The chlorination system must be designed on a rational basis and calculations justifying the equipment sizing and number of units and submitted for the whole operating range of flow rates for the type of control to be used. System design considerations must include the controlling wastewater flow meter (sensitivity and location), telemetering equipment, and chlorination controls. (7-1-26)
c. Piping systems must be as simple as practicable, specifically selected and manufactured to be suitable for chlorine service, with consideration for minimizing number of joints. Piping must be well supported and protected against temperature extremes. Venting of excess gas must be provided. Special considerations must be given to piping and fixture selection for hypochlorite and chlorine use. (7-1-26)
d. Standby equipment of sufficient capacity must be available to replace the largest unit during shutdowns. Spare parts must be available for all disinfection equipment to replace parts which are subject to wear and breakage. (7-1-26)
e. Housing. (3-31-22)
i. Gas chlorination equipment and chlorine cylinders must be housed in a building. If this building is used for other purposes, a gas-tight room must separate this equipment from any other portion of the building. Floor drains from the chlorine room must not be connected to floor drains from other rooms. Doors to this room must open only to the outside of the building and be equipped with panic hardware. Rooms must permit easy access to all equipment. Local and state safety requirements must be satisfied. (7-1-26)
ii. Electrical and ventilation equipment must comply with local and state codes. (7-1-26)
iii. Respiratory air-pac protection equipment must be available where chlorine gas is handled, and be stored at a convenient location, but not inside any room where chlorine is used or stored. Instructions for using the equipment must be posted. (7-1-26)
04. Dechlorination. (3-31-22)
a. Types. (3-31-22)
i. Dechlorination of wastewater effluent must be provided when required to meet effluent limits to reduce the toxicity due to chlorine residuals. (7-1-26)
ii. The type of dechlorination system must be selected considering the type of chemical storage required, amount of chemical needed, ease of operation, compatibility with existing equipment, and safety. (7-1-26)
b. The dosage of dechlorination chemical must consider the residual chlorine in the effluent, the final residual chlorine limit, and the form of the dechlorinating chemical used. (7-1-26)
c. The same requirements apply for standby equipment and spare parts as chlorination systems. See Subsection 500.03.d. (7-1-26)
d. The requirements for housing sulfur dioxide gas equipment must follow the same guidelines as used for chlorine gas. Refer to Subsection 500.03.e. for specific details. When using solutions of the dechlorinating compounds, the solutions must be stored in a room that meets the safety and handling requirements set forth in Subsection 450.07. The mixing, storage, and solution delivery areas must be designed to contain or route solution spillage or leakage away from traffic areas to an appropriate containment unit. (7-1-26)
e. The respiratory air-pac protection equipment is the same as for chlorine. See Subsection
500.03.e.iii. (7-1-26)
a. The following documents or other references acceptable to the Department must be used for UV system sizing and facility design. (7-1-26)
“Wastewater Engineering, Treatment and Reuse,” Metcalf and Eddy. (7-1-26)
ii. For recycled water applications, “Ultraviolet Disinfection Guidelines for Drinking Water and Water Reuse,” National Water Research Institute/AWWA Research Foundation. (7-1-26)
b. All UV disinfection must be designed based on expected ranges of UV transmittance (UVT). For facilities larger than five million gallons per day (5 mgd) (design peak hour flow), or facilities that have industries that vary flows throughout the year, collection of one (1) year’s worth of UVT data (four (4) times per day) prior to the PER is required unless otherwise approved by the Department. (7-1-26)
c. All UV disinfection facilities must include the following: (7-1-26)
i. A minimum of two (2) channels (or justification for using a smaller system); and (7-1-26)
ii. A minimum of two (2) banks of UV lamps per channel (or justification for using a smaller system). (7-1-26)
d. The PER for all UV disinfection facilities must include a description of the following: (7-1-26)
i. The redundancy provided; (7-1-26)
ii. The upstream flow splitting device (which splits flow to the two (2) or more UV channels); (7-1-26)
iii. Water level control device; (7-1-26)
iv. Method used to take a channel off-line for maintenance, and method to dewater a channel; (7-1-26)
v. Type of UV system technology (low-pressure low-intensity, low-pressure high-intensity, medium pressure, etc.), with consideration given to power consumption; (7-1-26)
vi. Summary of UVT data and collimated beam data; (7-1-26)
vii. Climate controls system requirements to ensure adequate UV system performance during summer peak temperature period; (7-1-26)
viii. Maintenance requirements including removal (cleaning) of biofilms from the channel walls upstream and downstream of the UV system; (7-1-26)
ix. Alarming and controls; (7-1-26)
x. Procedure used for UV system sizing; and (7-1-26)
xi. Design criteria must include: (7-1-26)
(1) Design UVT; (7-1-26)
(2) TSS; (7-1-26)
(3) Design water temperature range; (7-1-26)
(4) Dose; (7-1-26) (5) End of lamp life factor; (7-1-26) (6) Fouling factor; (7-1-26) (7) Quartz sleeve transmittance factor; (7-1-26) (8) Design peak hour flow; (7-1-26) (9) Existing minimum flow; (7-1-26) (10) Number of channels; (7-1-26) (11) Disinfection requirements (coliform concentration); and (7-1-26) (12) Maximum head-loss from upstream of the first bank to downstream of the last bank of lamps (lamp spacing divided by two (2)). (3-31-22)
e. Use of bioassay method of UV system sizing is encouraged if all manufacturers under consideration have existing bioassays performed using identical protocol, and the bioassay was performed under conditions similar to the design application. Use of the bioassay method of UV system sizing is discouraged if these conditions cannot be met. (7-1-26)
f. Closed chamber units will be reviewed on a case-by-case basis in accordance with Subsection 450.03.b. (7-1-26)
06. Ozone. Ozone systems for disinfection will be evaluated by the Department on a case-by-case basis. Design of these systems must be based upon experience at similar full-scale installations or thoroughly documented prototype testing of the wastewater. (7-1-26)
501. -- 509. (RESERVED)
510. FACILITY AND DESIGN STANDARDS FOR MUNICIPAL WASTEWATER SYSTEMS: SUPPLEMENTAL TREATMENT PROCESSES.
01. Chemical Treatment. Chemical treatment in various forms can be used to aid in phosphorus and nitrogen removal, pH adjustment, enhanced clarification, and sludge conditioning. (7-1-26)
a. Chemical treatment must be evaluated for each specific treatment process in the PER and must be compatible with other liquids, solids and air treatment processes. Laboratory tests such as jar tests or pilot-scale studies on actual process wastewater must be used to select appropriate chemicals and dosage ranges. (7-1-26)
b. When settling aids are used during the primary clarification process to enhance solids removal in the primary treatment process, the additional solids volume must be accounted for in pumping, solids handling, stabilization, and disposal processes. The coagulant must be added and mixed before the sedimentation process. Flocculants, if used, must be added after the coagulant. The design must provide for chemical addition points at several locations to give process personnel the opportunity to adjust for optimum performance. (7-1-26)
02. Filtration for Tertiary Treatment. Details for treatment facilities with tertiary treatment utilizing membrane, media, cloth, or reverse osmosis must be submitted and approved in the PER. In addition to the provisions of Section 411, the PER must include plant layout, calculations for hydraulic capacity and air required, filtration technology considered and the type and model selected, results from similar type filtration systems already in operation, and anticipated sludge production. (7-1-26)
511. -- 518. (RESERVED)
Prior to construction of a new septage transfer station or upon material modification of an approved existing station, the owner of the station must satisfy the following requirements. (7-1-26)
01. Design. Septage holding tanks, transfer/storage tanks, and transfer hoses for either type of tank will meet the applicable provisions of Subsections 519.01.a. through 519.01.c. (7-1-26)
a. All tanks will be watertight, not open to the air, and provided with containment structures to prevent the discharge of septage spills to the surrounding environment. (7-1-26)
b. All piping, transfer hoses, valves, and connections will be watertight, accessible, and capable of being cleaned, repaired, and replaced. (7-1-26)
c. All inlet and outlet connections will be constructed and maintained such that septage will not leak, spill, or overflow the holding tank. (7-1-26)
d. No septage holding or transfer/storage tank will be permitted within the one hundred (100) year flood plain as defined and delineated by the flood insurance rate maps published by the Federal Emergency Management Agency. (7-1-26)
e. Odor controls will be provided to mitigate nuisance odor during transfer. Odor control may be attained by employing appropriate setback distances to neighboring facilities, using appropriate air scrubbing technologies in conjunction with an enclosed transfer station or other suitably engineered configuration that provides assurances of minimal odor nuisances. (7-1-26)
f. The property is owned by the individuals operating the septage transfer station, or the property owner has granted permission to use the property. (7-1-26)
g. Septage transfer stations will provide total containment for the entire volume of the holding tanks and transfer/storage tanks in the event of spilled septage. (7-1-26)
h. Truck washing facilities will be constructed to retain all wash water on site. (7-1-26)
02. Plans and Specifications. In addition to the provisions of Section 400, plans and specifications for septage transfer stations will provide or identify: (7-1-26)
a. A map which identifies the proposed septage holding or transfer/storage tank location; (7-1-26)
b. The footprint of the proposed activity area; (7-1-26)
c. All access roads and access control measures; (7-1-26)
d. All roads, property boundary lines, and structures within two hundred (200) feet of the septage holding or transfer/storage tank location; any structures on the property; and any easements or rights-of-way which exist on the property; (7-1-26)
e. Surrounding land use within two hundred (200) feet of the footprint of the proposed activity area on which the septage holding or transfer/storage tank is proposed to be located; and (7-1-26)
f. A spill response plan, describing spill response equipment and disinfection and containment capability at the septage transfer station, must be submitted to and approved by the Department. (7-1-26)
03. Record Keeping. Every owner of a septage transfer station will maintain the following records for a minimum of five (5) years. (7-1-26)
a. For each load of septage received: (3-31-22)
i. The date received or picked up; (3-31-22)
ii. The name and address of the clients from whom the septage was received; and (7-1-26)
iii. The volume of the septage received, in gallons; and (3-31-22)
b. Records indicating the final disposal destinations for septage removed from the transfer/storage tank. (7-1-26)
520. FACILITY AND DESIGN STANDARDS FOR MUNICIPAL WASTEWATER SYSTEMS: HANDLING AND TREATMENT OF SEPTAGE AT A WASTEWATER TREATMENT FACILITY.
01. General. Septage disposal at a wastewater treatment plant is at the discretion of the owner of the wastewater treatment plant, unless other conditions apply. All treatment facilities require special design considerations prior to the acceptance of septage. Prior to acceptance of septage at a wastewater treatment facility, the plan for doing so must be addressed in the Facility Plan or PER. (7-1-26)
02. Characteristics. Prior to acceptance at a treatment facility, septage must be characterized. The U.S. EPA Handbook entitled "Septage Treatment and Disposal" 1984, EPA-625/6-84-009) may be used to estimate common parameters for septage and municipal wastewater. (7-1-26)
03. Considerations. An engineering evaluation of the existing treatment facility and the anticipated septage loading must be conducted prior to receiving septage at the treatment facility. For proposed treatment facility expansion and upgrading, the PER or facility plan must include anticipated septage loading in addressing treatment facility sizing and process selection. (7-1-26)
521. -- 599. (RESERVED)
600. LAND APPLICATION OF WASTEWATERS OR RECHARGE WATERS.
Land application of wastewater or recharge waters is subject to the following: (7-1-26)
01. Reuse Permit. IDAPA 58.01.17, "Recycled Water Rules," govern when a permit prior to land application or reuse of certain types of wastewater is necessary. (7-1-26)
02. Applied Waters Restricted to Premises. Wastewaters or recharge waters applied to the land surface must be restricted to the premises of the application site. (7-1-26)
03. Hazard or Nuisance Prohibited. Wastewaters or recharge waters must not create a public health hazard or a nuisance condition. (7-1-26)
04. Monitoring. Provision must be made for monitoring the quality of the groundwater in proximity of the application site. The groundwater monitoring program is subject to approval by the Department. All data and reports resulting from the groundwater monitoring program must be submitted to the Department upon request. To determine the frequency of monitoring and data submittal, the Department will consider the following: (7-1-26)
a. The nature and volume of wastewater or recharge water; (7-1-26)
b. The frequency and duration of application; and (3-31-22)
c. The characteristics of the soil mantle on and lithology underlying the application site. (3-31-22)
05. Basis for Evaluation. The evaluation for an approval to irrigate, either by sprinkling or flooding or surface spreading of wastewater or recharge water in the upper soil horizon as a method of treatment, must include, but will not be limited to, consideration of the following: (7-1-26)
a. The type and quantity of wastewaters or recharge water proposed for land application. In general, the organic constituents are to be biologically degradable and inorganic constituents must be utilized by vegetation or those organisms normally present in the soil. Other wastewaters or recharge waters will be considered provided it can be shown that land application will not adversely affect beneficial uses of waters. (7-1-26)
b. The nature of the soils and geologic formations underlying the application site. The entity proposing the activity must provide reasonable assurance that the soils and site geology will provide the required level of treatment and will not allow movement of pollutants into the underlying groundwater. (7-1-26)
c. The ability of the soil and vegetative cover on the application site to remove the pollutants contained in the applied waters through the combined processes of consumptive use and biological and chemical inactivation. (3-31-22)
01. Plans. Sludge can be disposed or utilized only in conformance with: (7-1-26)
a. A Department approved sludge disposal plan; (7-1-26)
b. A Department approved sludge use plan; or (7-1-26)
c. Procedures and in a manner approved by the Department on a site-by-site basis. (3-31-22)
02. Basis for Evaluation. Sludge disposal plans and sludge use plans will be evaluated by the Department regarding their protection of water quality and public health. (7-1-26)
03. Elements of Sludge Disposal Plans. Plans must at a minimum provide: (7-1-26)
a. Method of sludge transportation and disposal; (7-1-26)
b. Location of disposal and applicable acceptance criteria; (7-1-26)
c. Amount of sludge to be disposed, and whether the disposal is ongoing or one-time; and (7-1-26)
d. Emergency procedures, including spill cleanup, notification, and reporting procedures. (7-1-26)
04. Elements of Sludge Use Plans. Plans must at a minimum provide: (7-1-26)
a. That only stabilized sludge will be used; (7-1-26)
b. The criteria utilized for site selection, including: (3-31-22)
i. Soil description; (3-31-22)
ii. Geological features; (3-31-22)
iii. Groundwater characteristics; (3-31-22)
iv. Surrounding land use; (3-31-22)
v. Topography; and (3-31-22)
vi. Climate; (7-1-26)
c. A description of the transportation and application process; (7-1-26)
d. A statement detailing procedures to prevent application which could result in a reduction of soil productivity or in the percolation of excess nutrients; (7-1-26)
e. Identification of potential adverse health effects regarding the sludge and its proposed use; (7-1-26)
f. Delineation of methods or procedures to be used to alleviate or eliminate adverse health effects; (7-1-26)
g. Emergency procedures, including spill cleanup, notification, and reporting procedures; and (7-1-26)
h. Recordkeeping and reporting procedures. (7-1-26)
05. Reference to Federal Regulations. See Code of Federal Regulations, 40 CFR, Part 503, Standards for the Use or Disposal of Sewage Sludge. (3-31-22)
651. -- 659. (RESERVED)
Waivers from the provisions of these rules may be granted by the Director on a case-by-case basis upon demonstration by the person requesting the waiver(s) that such activities for which the waivers are granted are not necessary for the protection of public health and the environment, and that the facilities are satisfactorily operated and maintained. (7-1-26)
661. -- 999. (RESERVED)