Mo. Code Regs. Ann. tit. 10, § 20-8.110
PURPOSE: This rule provides the minimum criteria for the preparation of engineering reports and facility plans and specifications related to the design of wastewater systems. This rule is to be used with rules 10 CSR 20-8.110 through 10 CSR 20-8.210 for the planning and design of a wastewater treatment facility. It does not address all aspects of design, and the design engineer may refer to other appropriate reference materials so long as these minimum standards set forth in this rule are met.
(1) Applicability. Engineering reports and facility plans and specifications shall be prepared based on criteria contained in this rule, published standards, applicable federal and state requirements, standard textbooks, current technical literature, and applicable safety standards. In the event of any conflict between the above criteria, the requirement in this rule shall prevail.
(2) General. All documents submitted to the Missouri Department of Natural Resources (department) for the purpose of complying with this rule shall be prepared, signed, sealed, and dated by a Missouri registered professional engineer.
(B) Engineering Reports or Facility Plans.
volving collection systems, pumping stations, and force mains.
wastewater treatment facility projects and projects receiving department funding through the grant and loan programs under 10 CSR 20-4, Grants and Loans.
(3) Hydraulic and Organic Waste Load.
(A) Existing Systems shall—
erage and peak flows to calculate projections for hydraulic capacity;
sewers that will affect interceptor sewers and treatment facilities;
load to calculate projections for organic capacity; and
contributions of industrial sources in the calculations of projected capacity.
(B) New Collection and Wastewater Treatment Systems.
collection systems.
sign peak hourly flow, including origin of the flow estimates and any assumptions, shall be identified.
used in conjunction with a peaking factor from the following Equation 110-1, included herein.
Equation 110-1. Ratio of peak hourly flow to design average flow.
Peaking Factor = Q Peak Hourly / Q Design Avg = (18 + √P) / (4 + √P)
Where: Q Peak Hourly = design peak hourly flow Q Design Avg = design average flow P = Population in thousands
development, the likelihood of inflow and infiltration (I/I) contributions from existing service lines shall be evaluated.
be identified for all contributing parameters such as the design average five (5)-day Biochemical Oxygen Demand (BOD5).
(C) Drinking Water Use Records. Facilities proposing drinking water usage as the basis for design average flow must provide at least one (1)-year of drinking water use records in the following form:
ing water use records for facilities that discharge year-round; or
during the entirety of an operating season for facilities having critical operational schedules (e.g., recreational areas, campuses, and industrial facilities).
(D) Re-Rating a Wastewater Treatment Facility. A wastewater treatment facility owner must request department review and approval when proposing to re-rate an existing wastewater treatment facility’s current design hydraulic capacity or organic waste loading. An engineering re-rating analysis must demonstrate the wastewater treatment facility can reliably operate at the proposed re-rated loading rate. The re-rating analysis shall include the following:
the maximum monthly average flow, the maximum daily flow, and the ratio of the peak flow to annual average flow using the last five (5) years’ wastewater treatment facility. Include all calculations and assumptions.
water treatment facility’s average annual flow plus one (1) standard deviation for a wastewater treatment facility that will not be affected by future growth; or
pated changes from the existing flow for a wastewater treatment facility that will be affected by future growth.
loading based on the average daily organic load.
twenty-four (24)-hour composite samples of the influent wastewater per week, taken during days with representative flow, for a period of at least three (3) months during both wet and dry weather conditions;
unless monitoring of the parameter is not a requirement of the National Pollutant Discharge Elimination System (NPDES) permit: BOD5, Total Suspended Solids (TSS), ammonia, total nitrogen, and total phosphorus;
tion from subparagraph (3)(D)1.A and B. of this rule; and
if they are appropriately sized to provide adequate treatment based on the re-rated design organic waste load.
its design and peak capacity. Normally one (1) unit process will be most restrictive in terms of design capacity. Include solids processing, handling, and storage in this analysis.
ty’s ability to reliably and consistently comply with the NPDES permit effluent limitations and conditions.
(4) Engineering Report. Engineering reports shall include the following:
(5) Facility Plan. Facility plans shall include the following, in addition to the information in section (4) of this rule:
(E) Detailed Alternative Evaluation. Include the following for the alternatives to be evaluated in detail:
sions to the existing collection system including adequacy of portions not being changed by the project;
treat wet weather flows in a manner that complies with federal, state, and local regulations;
alternative in the facility plan. Also refer to 10 CSR 20-6.010(4) (A)5;
alternative in the facility plan;
when the project includes wastewater irrigation or subsurface soil dispersal;
site evaluation. Take appropriate measures to minimize adverse impacts when a site is critical with respect to the following items:
the present and planned future land use, including noise, potential odors, air quality, and anticipated solids processing and disposal techniques. Wastewater treatment facilities should be separate from habitation or any area likely to be built up within a reasonable future period and shall be separated in accordance with state and local requirements. Refer to 10 CSR 20-8.140(2)(C) for minimum separation distances;
CSR 20-8.140(2)(B);
features, or other geologic considerations of significance to the project;
by the department’s Missouri Geological Survey is required in the following instances:
stream determinations (gaining or losing);
structures. Earthen basin structures shall not be located in areas receiving a severe collapse potential rating. Earthen basin structures located in areas receiving a severe overall geologic limitation rating are reviewed on a case-by-case basis. Earthen basin structures located in areas receiving a moderate collapse potential rating with an appropriate engineering solution are reviewed on a case-by-case basis; and
subsurface soil dispersal sites);
vate wells shall be provided. When the proposed wastewater facilities will be near a water source or other drinking water facility, as determined by the Missouri Geological Survey or by the department’s Public Drinking Water Branch, include an evaluation addressing the allowable distance between these wastewater facilities and the water source. Refer to 10 CSR 20- 8.140(2)(C);
tion and depth to normal and seasonal high groundwater;
qualified soil scientist for all subsurface soil dispersal systems. Refer to section (7) of this rule;
any field tile or curtain drain in the immediate area of the proposed site;
and monitoring requirements;
for the outfall line; and
and assumptions used in the design of the project. Provide the basis for unit operation and preliminary unit process sizing;
site of the project and anticipated location and alignment of proposed facilities;
treatment facility alternatives, including all recycle flows;
and removal efficiencies through each unit operation in addition to total removal efficiency and effluent quality (both concentrations and mass);
gency operation measures as outlined in 10 CSR 20-8.140(7)(A);
rule. Provide a contingency plan, in the event that such new technology fails to meet the expected performance;
moval capabilities, including the footprint available for expansion or treatment facility modifications necessary for nutrient removal for each alternative;
natives considered and method selected consistant with the requirements of 10 CSR 20-8.170 and any conditions in the NPDES permit;
method and level of treatment (including solids processing, storage, and disposal) to be achieved during construction and include it in the facility plan. Refer to paragraph (9)(A)5. and subsection (10)(C) of this rule;
struction cost, annual operation and maintenance cost (including basis), and a twenty (20)-year present worth cost for each alternative;
mental information meeting the criteria in 10 CSR 20-4.050, for projects receiving funding through the state grant and loan programs; and
reports in accordance with 10 CSR 20-7, Water Quality; and
(6) New and Innovative Technology.
(A) Evaluation of Technology Performance. To determine if new technologies of wastewater treatment processes and equipment or applications have a reasonable and substantial chance of success, the facility plan prepared for department approval shall include the following:
engineering evaluations demonstrating the efficiency of processes or equipment;
methods that are sufficiently sensitive analytical methods for detecting, identifying, and measuring the concentrations of pollutants;
under various ranges of strength and flow rates (including diurnal variations) and waste temperatures over a sufficient length of time to demonstrate expected performance under the range of climatic and other conditions that may be encountered in the area of the proposed installations. A control group may be necessary to demonstrate effectiveness;
mance warranty including all exclusions or limitations on the warranty, when available;
assumptions clearly documented and explained;
functions;
pilot test work. For full-scale operating experience, include the length of time that each installation has been in operation. For pilot test work, include a copy of the associated pilot test plan and final pilot test results report;
operational issues that have occurred or may occur during the first year of operation;
needed to operate the proposed technology including an estimate of increased operator attention needed during start-up and the first year of operation; and
(B) Pilot Test or Demonstration Plan. Proposals for pilot tests and demonstration projects shall include the following in addition to the facility plan information in section (5) of this rule:
to why a pilot study or demonstration project is necessary to obtain additional engineering data;
experience;
pictures, drawings, or any other important information;
assumptions clearly documented and explained;
both direct and indirect;
methods that are sufficiently sensitive analytical methods for detecting, identifying, and measuring the concentrations of pollutants;
start, completion, and submittal of the pilot test or demonstration results report; and
(7) Soils Report.
(B) Soils Report. The soils report resulting from the investigation shall include the following information:
erosion, and other natural features that may influence the soil treatment area;
geologic risk factors affecting the soil’s ability to treat and disperse effluent, such as karst features, dense tills, clay pans, and fragipans;
identifying all applicable site features that could impact the soil treatment area(s). Previously prepared or otherwise available drawings or maps such as a survey prepared by a Missouri registered professional surveyor; an aerial photograph; a United States Geological Survey topographic map with the proposed soil treatment area clearly delineated; a United States Department of Agriculture Natural Resources Conservation Services county soil survey map with the proposed soil treatment area clearly delineated; or a digital orthophotograph prepared from a geographical information system may be used. The following shall be included on the drawings or maps:
tent of different soils clearly delineated;
existing roadways, and other hardscapes and proposed hardscapes, or related site disturbances;
wells, or geothermal systems, and surface water features that could either influence or be impacted by the proposed soil treatment area. For minimum separation distances, follow the provisions listed in 10 CSR 20-8.140(2)(C);
hibit, limit, or adversely impact the siting of a soil treatment area including, but not limited to: sinkholes, wetland vegetation, bedrock outcrops, areas with a slope greater than fifteen percent (15%), and existing or abandoned field or drainage tiles;
served easements and right-of-ways; and
clude the following:
bedrock) and the source of this information;
consideration the drainage and permeability of the soils and the distance to the limiting layer.
zon within the specific soil description;
this information;
holes or karst features) on the proposed site or in the surrounding area that may indicate vulnerability for surface water and groundwater contamination and the source of this information; and
logically control effluent and the source of this information.
(C) Imported Soils. When a facility is importing soils for the subsurface soil dispersal systems, the following shall be specified:
structure, and pore space;
consistency of the physical characteristics as close as possible to the original state upon delivery;
(10%) clay and less than fifteen percent (15%) organic debris present;
(4"–6") instead of one (1) thick layer; and
subsurface soil dispersal systems with the fill for the cap being imported soils.
(8) Summary of Design. A summary of design shall accompany the plans and specifications and must include the following:
(9) Plans.
(A) General.
nents on all plan sheets:
owner, and continuing authority (refer to 10 CSR 20-6.010(2) and 20 CSR 2030-2.050);
to a scale that allows necessary information to be seen plainly. Blueprints and hand-drafted plans are not acceptable.
the following:
views, which together with the specifications and general layouts, provide the working information for the contract and construction of the facilities;
location and outline form of equipment, location and size of piping, water levels, and ground elevations;
and below ground, that might interfere with the proposed construction or require isolation setback, particularly water mains and water supply structures (e.g., wells, clear wells, basins), gas mains, storm drains, and telephone, cable, and power conduits. Show the location of all existing and proposed water supply structures located within five hundred feet (500') of the proposed or existing wastewater treatment facility; and
Include test boring logs on the plans or in the specifications as an appendix.
must be included; and
procedure for operation during construction that complies with the plan outlined in paragraph (5)(E)15. and subsection (10)(C) of this rule.
(B) Plans of Sewers.
1. General plans. These plans shall show the following:
A. Geographical features.
or proposed streets and all streams or water surfaces. Include contour lines at suitable intervals;
and high and low water elevations of all water surfaces;
tinuing authority and the area to be sewered; and
of relevant existing and proposed sanitary and combined sewers draining to the treatment facility concerned.
the following:
one hundred feet (100') to the inch and a vertical scale of not more than ten feet (10') to the inch;
and shown on the same sheet;
length between manholes; invert and surface elevation at each manhole; grade of sewer between each two (2) adjacent manholes; and any special construction features. Number all manholes on the plan and correspondingly number them on the profile;
profile of the sewer where there is any question of the sewer being sufficiently deep to serve any residence;
phons, concrete encasements, elevated sewers, etc.; and
G. Detail drawings to show the following:
bed and ordinary high water mark, normal, and low water levels;
tions; and
holes, inspection chambers, inverted siphons, regulators, tide gates, and elevated sewers.
(C) Plans of Wastewater Pumping Stations.
1. Location plans. These plans must show the following:
tary area;
and
where applicable:
installation of future pumps;
system upon occasion of power failure;
sewers when all installed pumps are in operation;
valves, level control switches, hatches, safety equipment, ventilation equipment, and hoisting equipment; and
provisions listed in 10 CSR 20-8.140(2)(B).
(D) Plans of Wastewater Treatment Facilities.
ing:
remainder of the system; and
with relation to streams and the point of discharge of treated effluent.
treatment facility shall show—
various units and showing utility systems serving the facility processes;
(identify materials handled and direction of flow through pipes, including arrangements for independent operation);
supernatant liquor, recycle streams, and solids; and
where applicable:
and proposed treatment facilities and solids handling facilities;
water to which the facility effluent is to be discharged;
of all pumps, blowers, motors, and other mechanical devices;
flow in hydraulic profile with wastewater, supernatant liquor, and solids flow through the treatment facility;
and profile;
covered by the specifications or facility plan; and
provisions listed in 10 CSR 20-8.140(2)(B).
(10) Specifications.
(B) The technical specifications accompanying construction drawings shall include the following, but not be limited to all construction information not shown on the drawings which is necessary to inform the builder, in detail, of the design requirements for the quality of materials, workmanship, and fabrication of the project:
rating of equipment;
electrical equipment (including machinery, valves, piping, and jointing of pipe);
ters;
slag);
necessary to meet design standards; and
ponent units. It is suggested that these performance tests be conducted at design load conditions wherever practical.
(11) Revisions to Approved Plans or Specifications.
AUTHORITY: section 644.026, RSMo 2016.* Original rule filed Aug. 10, 1978, effective March 11, 1979. Amended: Filed Sept. 14, 2010, effective June 30, 2011. Amended: Filed June 15, 2018, effective Feb. 28, 2019.
*Original authority: 644.026, RSMo 1972, amended 1973, 1987, 1993, 1995, 2000.