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.
ed for projects involving collection systems, pumping stations, and force mains.
projects involving 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—
represent the average and peak flows to calculate projections for hydraulic capacity;
upstream combined sewers that will affect interceptor sewers and treatment facilities;
sent organic waste load to calculate projections for organic capacity; and
organic waste load contributions of industrial sources in the calculations of projected capacity.
(B) New Collection and Wastewater Treatment Systems.
facilities and new collection systems.
age flow and design peak hourly flow, including origin of the flow estimates and any assumptions, shall be identified.
flow value shall be 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
to serve existing development, the likelihood of inflow and infiltration (I/I) contributions from existing service lines shall be evaluated.
load estimates shall 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:
months of drinking water use records for facilities that discharge year-round; or
use records 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:
annual average flow, 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.
using the wastewater 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
using the anticipated changes from the existing flow for a wastewater treatment facility that will be affected by future growth.
design organic waste loading based on the average daily organic load.
of at least three (3) 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;
ing parameters 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;
capacity evaluation from subparagraph (3)(D)1.A and B. of this rule; and
cess to determine if they are appropriately sized to provide adequate treatment based on the re-rated design organic waste load.
each unit process for 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.
change of the facility’s ability to reliably and consistently comply with the NPDES permit effluent limitations and conditions.
pated rate of growth. (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:
the proposed revisions to the existing collection system including adequacy of portions not being changed by the project;
to transport and treat wet weather flows in a manner that complies with federal, state, and local regulations;
include it as an alternative in the facility plan. Also refer to 10 CSR 20-6.010(4)(A)5;
and include it as an alternative in the facility plan;
CSR 20-8.200(2) when the project includes wastewater irrigation or subsurface soil dispersal;
ing criteria during site evaluation. Take appropriate measures to minimize adverse impacts when a site is critical with respect to the following items:
treatment process with 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;
restrictions;
topography of the site;
expansion;
provisions listed in 10 CSR 20-8.140(2)(B);
depth to bedrock, karst features, or other geologic considerations of significance to the project;
uation conducted by the department’s Missouri Geological Survey is required in the following instances:
facilities to identify stream determinations (gaining or losing);
outfalls;
tions to earthen basin 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
ater irrigation sites, subsurface soil dispersal sites);
ing public and private 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);
ability for construction and depth to normal and seasonal high groundwater;
conducted by a qualified soil scientist for all subsurface soil dispersal systems. Refer to section (7) of this rule;
discharge point of any field tile or curtain drain in the immediate area of the proposed site;
future effluent quality and monitoring requirements;
waterbody access for the outfall line; and
of site availability;
engineering criteria and assumptions used in the design of the project. Provide the basis for unit operation and preliminary unit process sizing;
identifying the site of the project and anticipated location and alignment of proposed facilities;
flow diagram of treatment facility alternatives, including all recycle flows;
mated loadings to and removal efficiencies through each unit operation in addition to total removal efficiency and effluent quality (both concentrations and mass);
cussion of emergency operation measures as outlined in 10 CSR 20-8.140(7)(A);
section (6) of this rule. Provide a contingency plan, in the event that such new technology fails to meet the expected performance;
sion of nutrient removal capabilities, including the footprint available for expansion or treatment facility modifications necessary for nutrient removal for each alternative;
and disposal alternatives considered and method selected consistant with the requirements of 10 CSR 20-8.170 and any conditions in the NPDES permit;
Develop a plan for the 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;
mates for capital construction cost, annual operation and maintenance cost (including basis), and a twenty (20)-year present worth cost for each alternative;
additional environmental information meeting the criteria in 10 CSR 20-4.050, for projects receiving funding through the state grant and loan programs; and
reviews, studies, or reports in accordance with 10 CSR 20-7, Water Quality; and
the selected project from the alternatives considered under paragraph (5)(E) of this rule, including the financing considerations and recommendations for implementation of the plan. Provide a project implementation schedule identifying project milestones. 10 CSR 20-8
(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:
test results and engineering evaluations demonstrating the efficiency of processes or equipment;
protocol and test methods that are sufficiently sensitive analytical methods for detecting, identifying, and measuring the concentrations of pollutants;
posited samples, 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;
ranty and performance warranty including all exclusions or limitations on the warranty, when available;
lations, and all assumptions clearly documented and explained;
cess or equipment functions;
operating experience or 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;
start-up issues and operational issues that have occurred or may occur during the first year of operation;
knowledge and skills 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:
an explanation as to why a pilot study or demonstration project is necessary to obtain additional engineering data;
parameters and related experience;
schematic diagrams, pictures, drawings, or any other important information;
lations, and all assumptions clearly documented and explained;
mental impacts, both direct and indirect;
protocol and test methods that are sufficiently sensitive analytical methods for detecting, identifying, and measuring the concentrations of pollutants;
evaluation including 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:
tion;
rock outcrops, erosion, and other natural features that may influence the soil treatment area;
ing conditions or geologic risk factors affecting the soil’s ability to treat and disperse effluent, such as karst features, dense tills, clay pans, and fragipans;
drawings, or maps 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:
pits with the extent of different soils clearly delineated;
and structures;
vated or fill areas, existing roadways, and other hardscapes and proposed hardscapes, or related site disturbances;
wells, abandoned 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);
tions that would prohibit, 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;
proposed, and observed easements and rightof-ways; and
clusions must include the following:
ment area;
water table, fragipan, bedrock) and the source of this information;
rates that take into consideration the drainage and permeability of the soils and the distance to the limiting layer.
for each soil horizon within the specific soil description;
and the source of this information;
bedrock outcrops, sinkholes 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
to treat and hydrologically 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:
form in texture, structure, and pore space;
uniformity and consistency of the physical characteristics as close as possible to the original state upon delivery;
than ten percent (10%) clay and less than fifteen percent (15%) organic debris present;
layer;
of four to six inches (4"–6") instead of one (1) thick layer; and
cal separation for the 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.
following components on all plan sheets:
name of the project, owner, and continuing authority (refer to 10 CSR 20-6.010(2) and 20 CSR 2030-2.050);
ings;
legible plans drawn to a scale that allows necessary information to be seen plainly. Blueprints and hand-drafted plans are not acceptable.
plans consisting of the following:
and supplementary views, which together with the specifications and general layouts, provide the working information for the contract and construction of the facilities;
of structures, the location and outline form of equipment, location and size of piping, water levels, and ground elevations;
utilities, both above 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
where applicable. Include test boring logs on the plans or in the specifications as an appendix.
treatment facilities must be included; and
tion must specify the 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.
the following:
A. Geographical features.
Clearly show existing or proposed streets and all streams or water surfaces. Include contour lines at suitable intervals;
flow in all streams and high and low water elevations of all water surfaces;
ary lines of the continuing authority and the area to be sewered; and
and direction of flow of relevant existing and proposed sanitary and combined sewers draining to the treatment facility concerned.
submitted showing the following:
of not more than one hundred feet (100') to the inch and a vertical scale of not more than ten feet (10') to the inch;
ing horizontal scale and shown on the same sheet;
material, and type; 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;
ment floor on the profile of the sewer where there is any question of the sewer being sufficiently deep to serve any residence;
such as inverted siphons, concrete encasements, elevated sewers, etc.; and
lowing:
tions of the stream bed and ordinary high water mark, normal, and low water levels;
joints and cross-sections; and
nances such as manholes, inspection chambers, inverted siphons, regulators, tide gates, and elevated sewers.
(C) Plans of Wastewater Pumping Stations.
show the following:
utary area;
aries with the tributary area;
tion and force main; and
the following, where applicable:
ing provisions for installation of future 10 CSR 20-8
pumps;
in the collection system upon occasion of power failure;
downstream gravity sewers when all installed pumps are in operation;
tions;
such as pumps, valves, level control switches, hatches, safety equipment, ventilation equipment, and hoisting equipment; and
protection, follow the provisions listed in 10 CSR 20-8.140(2)(B).
(D) Plans of Wastewater Treatment Facilities.
include the following:
in relation to the remainder of the system; and
indicate its location with relation to streams and the point of discharge of treated effluent.
posed wastewater treatment facility shall show—
facility structures;
ing the flow through various units and showing utility systems serving the facility processes;
for unit isolation (identify materials handled and direction of flow through pipes, including arrangements for independent operation);
flow of wastewater, supernatant liquor, recycle streams, and solids; and
vations.
the following, where applicable:
tions of all existing and proposed treatment facilities and solids handling facilities;
level of the body of water to which the facility effluent is to be discharged;
operating capacity of all pumps, blowers, motors, and other mechanical devices;
peak hourly hydraulic flow in hydraulic profile with wastewater, supernatant liquor, and solids flow through the treatment facility;
age volumes in plan and profile;
tures not otherwise covered by the specifications or facility plan; and
protection, follow the 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:
characteristics, and rating of equipment;
mechanical and electrical equipment (including machinery, valves, piping, and jointing of pipe);
mentation, and meters;
sand, gravel, or slag);
equipment as necessary to meet design standards; and
facilities and component 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.