PURPOSE: The following criteria have been prepared as a guide for the design of land treatment systems. This rule is to be used with rules 10 CSR 20-8.110–10 CSR 20-8.220 for the planning and design of the complete treatment facility. This rule reflects the minimum requirements of the Missouri Clean Water Commission as regards adequacy of design, submission of plans, approval of plans and approval of completed sewage works. Deviation from these minimum requirements will be allowed where sufficient documentation is presented to justify the deviation. These criteria are taken largely from Great Lakes-Upper Mississippi River Board of State Sanitary Engineers Recommended Standards for Sewage Works and are based on the best information presently available. These criteria were originally filed as 10 CSR 20-8.030. It is anticipated that they will be subject to review and revision periodically as additional information and methods appear. Addenda or supplements to this publication will be furnished to consulting engineers and city engineers. If others desire to receive addenda or supplements, please advise the Clean Water Commission so that names can be added to the mailing list.

Editor’s Note: The secretary of state has determined that the publication of this rule in its entirety would be unduly cumbersome or expensive. The entire text of the material referenced has been filed with the secretary of state. This material may be found at the Office of the Secretary of State or at the headquarters of the agency and is available to any interested person at a cost established by state law.

1. (1) Definitions.

   1. (A) Definitions as set forth in the Clean Water Law and 10 CSR 20-2.010 shall apply to those terms when used in this rule, unless the context clearly requires otherwise. Where the terms shall and must are used, they are to mean a mandatory requirement insofar as approval by the agency is concerned unless justification is presented for deviation from the requirements. Other terms, such as should, recommend, preferred and the like, indicate discretionary requirements on the part of the agency and deviations are subject to individual consideration.
   2. (B) Land treatment is the application of wastewater at rates up to the maximum amount which can be renovated by the soil— plant filter without detrimental effects to surface or groundwater soils or crops.
   3. (C) Wastewater reuse is the application of wastewater for maximum economic return from the cropping system. Application rates will approximate the irrigation deficit and normally will not exceed twelve inches (12") (30 cm) per year.

2. (2) Exceptions.

   1. (A) This rule shall not apply to facilities designed for twenty-two thousand five hundred (22,500) gallons per day (85.4 m3) or less (see 10 CSR 20-8.020 for the requirements for those facilities).
   2. (B) This rule shall not apply to land application systems designed for wastewater reuse. Due to the low application rates, little need for regulation exists at this time.
3. (3) Preliminary Considerations. Land treatment is the application of wastewater at rates not to exceed the maximum which can be renovated by the soil and vegetation without detrimental effects to surface or groundwater, soils or crops. Land treatment installations are to be used where the waste contains pollutants which can be successfully renovated through organic decomposition and the adsorptive, physical and chemical reactions in the soil and vegetation. The land treatment of wastewater may recharge the local groundwater or reemerge into streams; therefore, the quality, direction and rate of movement and local use of the groundwater, present and future, are important considerations in evaluating a proposed site. It is essential to maintain an aerated zone in the soil to provide good vegetative growth and removal of nutrients. A groundwater mound may develop after the system is in use. Major factors in the design of land treatment systems are topography, soils, geology, hydrology, weather, agricultural practice, crop, use of crop, adjacent land use, equipment selection and installation.

4. (4) Design Report. The design report shall include maps and diagrams as noted in the following. It shall also include any additional material that is pertinent about the location, geology, topography, hydrology, soils, areas for future expansion and adjacent land use.

   1. (A) Location.

      1. 1. A copy of the USGS topographic map

of the area (seven and one-half (7 1/2)-minute series where published), similar map or aerial photograph showing the exact boundaries of the spray field.

1. 2. A topographic map of the total area

under consideration by the applicant at a scale of approximately one inch to fifty feet (1":50') (2.54:15.2 cm) with appropriate contour interval. It should show all buildings, the waste disposal system, the spray field boundaries and buffer zone. An additional map should show the spray field topography in detail with a contour interval of two feet (2') (61 cm) and include buildings and land use on adjacent lands within one-fourth (1/4) mile of the project boundary.

1. 3. Water supply wells which might be

affected shall be located and identified as to uses—for example, potable, industrial, agricultural and class of ownership; for example, public, private, etc.

1. 4. All abandoned wells, shafts, etc.,

where possible, should be located and identified. Pertinent information thereon shall be furnished.

1. (B) Geology.

   1. 1. Geologic formation’s name and the

rock types at the site.

1. 2. Degree of weathering of the bedrock.
2. 3. Character and thickness of the surfi-

cial deposits.

1. 4. Local bedrock structure including the

presence of faults, fractures and joints.

1. 5. The presence of any solution open-

ings and sinkholes in carbonate terrain.

1. 6. The source of the information in

(4)(B)1.–5. must be indicated.

1. (C) Hydrology.

   1. 1. The depth to seasonal and permanent

highwater tables (perched and/or regional) must be given, including an indication of seasonal variations.

1. 2. The direction of groundwater move-

ment and the point(s) of discharge must be shown on one (1) of the attached maps.

1. 3. Chemical analyses indicating the

quality of groundwater at the site must be included.

1. 4. Indicate the source of the data in

(4)(C)1.–3.

1. 5. The following information shall be

provided from existing wells and from the test wells as may be necessary:

1. A. Construction details—where avail-

able. Depth, well log, pump capacity, static levels, pumping water levels, casing, grout material and the other information as may be pertinent; and

1. B. Groundwater quality. For example,

nitrates, total nitrogen, chlorides, sulfates, pH, alkalinities, total hardness, coliform bacteria and metal ions.

1. 6. A minimum of one (1) groundwater

monitoring well, where deemed necessary by the DGLS, must be drilled in each dominant direction of groundwater movement and between the project site and public well(s) and/or high capacity private wells with provision for sampling at the surface of the water table and at five feet (5') (1.5 m) below the water table at each monitoring site. The location and construction of the monitoring well(s) must be approved by the agency. These may include one (1) or more of the test wells where appropriate.

1. (D) Evaluation of Effluent to be Applied. Representative samples are essential to properly evaluate the effluent. Where the discharge is from a sewage treatment plant, twenty-four (24)-hour samples proportioned to the rate of flow will be needed to obtain a representative sample. In cases where the effluent is stored for several days or longer, a single sample of the effluent will suffice. Analyses which will be of major importance will be for total suspended solid (TTS), a volatile suspended solid (VSS), sodium, calcium, magnesium, electrical conductivity (EC), nitrogen, phosphorous, metal ions and fluoride. The sodium absorption ratio (SAR) should be calculated from sodium, calcium and magnesium determination.

2. (E) Soils. All soils investigation should be performed by a qualified soil scientist.

   1. 1. A soils map should be furnished of

the spray field, indicating the various soil types. This may be included on the largescale topographic map. Soils information can normally be secured through the USDA Soil Conservation Service.

1. 2. The soils should be named and their

texture described.

1. 3. Slopes and agricultural practice on

the spray field are closely related. Slopes on cultivated fields should be limited to four percent (4%) or less. Slopes on sodded fields should be limited to eight percent (8%) or less. Forested slopes should be limited to eight percent (8%) for year-round operation but some seasonal operation slopes up to fourteen percent (14%) may be acceptable.

1. 4. The thickness of soils should be indi-

cated. Indicate how determined.

1. 5. Data should be furnished on the

exchange capacity of the soils. In cases of industrial wastes particularly, this information must be related to special characteristics of the wastes.

1. 6. Information must be furnished on the

internal and surface drainage characteristics of the soil materials. Location and depths to impermeable or restricted horizons should be indicated.

1. 7. Proposed application rates should

take into consideration the drainage and permeability of the soils and the distance to the water table.

1. (F) Agricultural Practice.

   1. 1. The present and intended soil-crop

management practices, including forestation, shall be stated.

1. 2. Pertinent information shall be fur-

nished on existing drainage systems.

1. 3. When cultivated crops are anticipat-

ed, a cropping and harvesting program by a qualified agronomist shall be included.

1. (G) Adjacent Land Use.

   1. 1. Present and anticipated use of the

adjoining lands must be indicated. This information can be provided on one (1) of the maps and may be supplemented with notes.

1. 2. The plan shall show existing and pro-

posed screens, barriers or buffer zones to prevent blowing spray from entering adjacent land areas.

1. 3. If expansion of the facility is antici-

pated, the lands which are likely to be used for expanded spray fields must be shown on the map.

1. (5) System Design.

   1. (A) Treatment Before Land Application. The treatment of wastewater prior to application shall be adequate to prevent nuisance conditions from occurring in the treatment facility, in the storage basins or on the application site. When spray application is to be used, the system must also minimize the aerosol spread of pathogen. A primary lagoon cell loaded at a rate not to exceed thirty-four pounds (34 lbs.) BOD5/acre/day (38 kilograms BOD5/hectare/day) will be considered adequate to avoid nuisance conditions. Detention time of sixty (60) days or greater will be considered adequate to achieve pathogen reduction to acceptable levels. Other treatment methods may be used to meet these requirements and will be reviewed on a case-by-case basis.
   2. (B) Storage Requirements. Storage shall be provided for the maximum capacity required to accommodate wastewater flows in excess of quantities which can be irrigated during the wettest year in ten (10). Computations for storage shall consider possible increases in wastewater flow during wet weather. If discharge to surface waters is permitted during portions of the year, storage facilities should be adequate to store excess wastewater flow during the period when discharge is not permitted. National Weather Service records should be used to estimate the number of days that weather will prevent the application of wastewater to the land.
   3. (C) Application Rates. Application rates shall be determined for each individual site based on topography, soils, geology, hydrology, weather, agricultural practice, adjacent land use and application method. A balance calculation for water and each significant parameter should be prepared to show that the system performance meets the requirements of 10 CSR 20-7.031 Water Quality Standards. The agency will consider comments from the Division of Geology and Land Survey, the Soil Conservation Service and University of Missouri-Extension Division in evaluating the proposed application rate.
2. (6) System Monitoring. An appropriate monitoring system shall be provided to determine the quality of water leaving the land treatment site and entering surface and/or ground water. Analysis of soil and plant tissue samples may be required to monitor the effect of the wastewater on the soil and crop.
3. (7) Fencing. The project area shall be enclosed with a suitable fence to preclude livestock and discourage trespassing. A vehicle access gate of sufficient width to accommodate mowing equipment should be provided. All access gates should be provided with locks.
4. (8) Warning Signs. Appropriate signs should be provided along the fence around the project boundaries to designate the nature of the facility and advise against trespassing.

AUTHORITY: section 644.026, RSMo Supp. 1988.* Original rule filed Aug. 10, 1978, effective March 11, 1979.

*Original authority 1972, amended 1973, 1987, 1993.