Element 7 - Disposition of all Residual Wastes

Ensuring adequate controls over the disposition of all residual waste or sludge from any water treatment processing is authorized under state authority by adding sludge requirements to the state Water Pollution Control Operating Permit. Sludge is a residual of the wastewater treatment process, the byproduct of the industrial treatment process of raw wastewater and is the result of contaminants removed from the wastewater stream. Sludge that meets the requirements for land application is called biosolids. The Missouri Department of Natural Resources requires state operating permits for all persons who operate, use or maintain facilities for the storage, treatment or disposal of sludge and/or biosolids as well as construction permits for those who build such facilities for storage, treatment or disposal. The department administers a state biosolids program. The U.S. Environmental Protection Agency administers a separate national biosolids programs. Missouri is not delegated to administer this program.

Facilities must meet the applicable control technology for sewage sludge treatment, use, and disposal as published by EPA and, applicable state standards and limitations in the Missouri Clean Water Law.

The Missouri Department of Natural Resources and the University of Missouri Cooperative Extension Services have developed guidance documents WQ 420 to WQ 449 for permittees designed to promote safe use and disposal of biosolids.

Missouri Biosolids Program

The Missouri Biosolids Program operates in conjunction with the delegated NPDES permit program for wastewater treatment facilities. A separate National Biosolids Program is administered by the EPA and has independent permitting and technical requirements under federal regulations. Missouri is delegated to administer NPDES permits, but is not delegated for the NPDES Biosolids Permitting Program. The state addresses any violations to water quality standards, while technical violations of federal regulations are referred to EPA. NPDES sludge permitting regulations are authorized under 40 CFR Part 122, Part 501, and Part 503. Requirements for states to assume delegation of the national program are authorized in 40 CFR Part 501. The Missouri Biosolids Program has been in place since 1982, preceding the first federal rules in 40 CFR Part 503 issued in 1993.

The Missouri Department of Natural Resources and the University of Missouri Extension Services have developed guidance documents designed to promote safe use and disposal of biosolids for permittees. Standard Conditions Part III in NPDES permits incorporates the University Extension water quality guidance documents. Other applicable state laws involving use and disposal of sewage sludge include the Missouri Fertilizer Law, administered by the Director of the Missouri Agricultural Experiment Station, and the Solid Waste Management Law, administered by the Missouri Department of Natural Resources.

Construction Permits

A state construction permit is required by 10 CSR 20-6.015 for all persons who build, erect, alter or replace facilities for sludge or biosolids storage, treatment, and disposal from domestic wastewater facilities. Revisions to 10 CSR 20-6.010(4)(C) would exempt sludge processing equipment, if made in the near future. A fee based on the size of the facility is required by 10 CSR 20-6.011 for each construction permit application. Each application must include engineering plans, specifications and biosolids/sludge management plans. Plans must be developed according to state design regulations as published in 10 CSR 20-8.020.

Operating Permits

The Missouri Biosolids Program operates in conjunction with the delegated NPDES permit program for wastewater treatment facilities by adding sludge requirements into state operating permits. A state operating permit is required, unless exempted, for all persons who operate, use or maintain facilities for the storage, treatment or disposal of sludge and/or biosolids.

Domestic Sludge/Residuals

Domestic sludge is a solid by-product that accumulates when domestic wastewater is treated in a wastewater treatment facility. It must be removed periodically to keep the facility operating properly. The department writes permits for wastewater treatment under the state’s effluent regulations and NPDES requirements. These permits allow treated water to be discharged into state waters or irrigated onto crop, forest, or pasture land. State operating permits also address sludge in Standard Conditions Part III and require compliance with Part 503 federal regulations.

Industrial Sludge/Residuals

The definition for industrial waste sources under the Missouri Clean Water Law includes all facilities that are not domestic waste sources, namely, wastewater industrial facilities. Industrial sludge is generated by industries not connected to publicly owned treatment works (POTWs) and/or by industries connected to POTWs that require pretreatment of wastewater. The department issues state operating permits to industrial facilities that produce sludge during wastewater treatment or generate residuals as a byproduct of manufacturing processes. These residues must be disposed of by land application, landfill and/or incineration. Industrial permits are written under state regulations and 40 CFR Part 503 regulations.

A generating industry is required to pretreat industrial wastes to reduce pollutants to acceptable levels prior to discharge into a POTW. Sludge removed by the industrial pretreatment process is the responsibility of the generating industry, and has the same requirements as other industrial sludge. Industries may land apply part or all of their waste materials depending on waste characteristics, regulatory requirements, permittee desires and site-specific factors.

Domestic Sludge Land Application: Biosolids

Sludge meeting requirements for land application is called biosolids. Department of Natural Resources Chapter 8 regulations contain the requirements for use and disposal of wastewater sludge. Biosolids are useful to crop and soil requirements by providing nutrients and organic matter. They may also contain heavy metals and other substances that could affect soil productivity and quality of food. Before sludge is applied to crop, forest, or pasture land, the organic and bacterial contents are treated to levels deemed necessary to prevent nuisance odors and public health hazards. Biosolids, as it applies to domestic sludge, must meet treatment process criteria for both pathogens and metal pollutant limitations for beneficial use. Other measures would be required if the processed biosolids are spread on dairy pastures or crops used for human consumption.

Standard Conditions Part III in the state operating permit includes limitations and monitoring requirements, operation and reporting requirements, and best management practices for land application. Best management practices include nutrient management, soil conservation practices and other requirements that ensure biosolids are used properly when stored or disposed. A primary emphasis of the operating permit is to verify that land application is being operated according to an approved plan and that water quality protection is maintained.

Form R – Permit Application for Land Application of Industrial Wastewater Biosolids and Residuals was developed to specifically address land application facilities. This form supplements other permit application forms. Form R contains details of supporting documentation needed to address the regulatory requirements to characterize waste and soils.