Element 1 - State Pretreatment Responsibilities

Pretreatment is the reduction of the amount of pollutants, the elimination of pollutants, or the alteration of the nature of pollutant properties in wastewater before or in lieu of discharging such pollutants into a Publically Owned Treatment Works (POTW).

The CWA Section 307 established a program to address indirect discharges for industries that discharge to a POTW. The pretreatment component of the NPDES permit is part of the National Pretreatment Program.

The program is a cooperative effort of the federal, state and local regulatory environmental agencies established to protect water quality.  There are currently about 45 approved and active pretreatment programs in the state.  Through an agreement with the U.S. Environmental Protection Agency (EPA) in the early 1980s, the Missouri Department of Natural Resources became the approval authority for delegating control authority to cities and their POTWs.  Missouri state law authorizes control authorities (cities/POTWs) to issue and enforce pretreatment permits.  Missouri’s General Pretreatment Regulation, 10 CSR 20-6.100 effective October 30, 2012, incorporates the federal general pretreatment regulation 40 CFR 403 and those federal categorical standards in 40 CFR 405-471 that have pretreatment requirements.

Since the mid-1980s, Missouri requires cities to have a state-approved pretreatment program when certain industries are connected to the POTW.  The pretreatment program requires industries to meet numeric limits on pollutants and today's pretreatment program is required to employ best management practices to control pollutants that are discharged into city sewers.

General pretreatment regulations require all POTWs with design flows greater than 5 million gallons per day and receiving industrial discharges that are subject to federal limitations or that pass through or interfere with the operation of the POTW to develop and implement an approved pretreatment program.  At the discretion of the department, smaller POTWs can also be required to develop programs.  The State of Missouri as approval authority will review and approve a cities pretreatment program submission.  The state will put a pretreatment program (or a substantial modification) on public notice before approval.  A substantial modification is a modification that generally has less stringent requirements for the regulated industries.  The public notice of intent to approve a pretreatment program or substantial modification is posted at the web site: http://dnr.mo.gov/env/wpp/pretreatment.htm

In cities with an approved pretreatment program, the POTW is the regulating authority for all Industrial Users contributing wastewater to POTW’s.  Local authorities incorporate pollutant limits and best management practices within their permit process for Significant Industrial Users.  These same authorities are responsible for the staffing and funding of their pretreatment programs.

An Industrial User permit describes, at a minimum, the duration of the permit, a statement of conditions for transferability, the effluent limits, monitoring and reporting requirements, and a statement of applicable civil and criminal penalties and any compliance schedule.

The requirements of an Industrial User permit reflect the most stringent of the applicable federal and local pretreatment standards.  Pretreatment standards for certain categories of industries are in the federal regulations at 40 CFR parts 405 through 471. The general and specific prohibitions are in the federal general pretreatment regulation at 40 CFR 403.5, adopted by the State of Missouri.  A city’s local limits are approved by the State of Missouri and the legal authority to implement is in city ordinance.

Local control authorities (cities/POTWs) are required to develop local limits, or demonstrate that local limits are not necessary.  These local limits are calculated as part of the initial pretreatment program submission and are reviewed when conditions change, or at least once in a NPDES permit period.

Approximately 30 Industrial Users in Missouri are located in cities that do not have approved pretreatment programs.  The State of Missouri is the control authority for those Industrial Users in cities that do not have an approved pretreatment program.  In accordance with Missouri Revised Statutes subsection 644.026(13), the State of Missouri cannot issue an Industrial User permit.  For Industrial Users subject to the categorical standards in 40 CFR 405-471, the state will ask for compliance (in writing) with federal and state pretreatment standards, monitor the industries, and report compliance to EPA Region 7.  Where an Industrial User is not adequately controlled to protect the POTW, the State of Missouri will require that the city/POTW develop a pretreatment program as a NPDES permit condition.

State Pretreatment Responsibilities

Through a formal agreement with EPA Region 7, the state administers the National Pretreatment

Program in Missouri. The duties associated with program administration include the following:

  • On-site reviews of local POTW programs, which may consist of Pretreatment Compliance Inspections or Pretreatment Audits
  • Reviewing annual pretreatment reports submitted by local POTW programs
  • Reviewing and approving new local POTW programs and modifications to existing programs
  • Acting as control authority for categorical Industrial Users discharging to POTWs without a local pretreatment program
  • Reviewing all new or modified NPDES permits issued to POTWs to ensure that the appropriate pretreatment requirements are included
  • Maintaining a list of pretreatment cities
  • Providing technical assistance and general information to POTWs, industries, consultants and the general public

References