Treatment Agreements for Significant Industrial Users

A treatment agreement (TA) is needed if a Significant Industrial User (SIU) discharges to a publicly owned treatment works (POTW). SIU means an industrial user of a POTW that meets any one of the following conditions:

1. Discharges an average of 25,000 gallons per day or more of process wastewater excluding sanitary, noncontact cooling and boiler blowdown wastewater;
   
   
2. Contributes a process waste stream which makes up 5 percent or more of the average dry weather hydraulic or organic capacity of the POTW;
   
   
3. Is subject to Categorical Pretreatment Standards under 40 CFR 403.6 and 40 CFR Chapter I, Subchapter N; or
   
   
4. Is designated by the department as a significant industrial user on the basis that the contributing industry, either singly or in combination with other contributing industries, has a reasonable potential for adversely affecting the operation of or effluent quality from the POTW or for violating any pretreatment standards or requirements.

Upon a finding that an industrial user meeting the criteria in paragraph "1" or "2" of this definition has no reasonable potential for adversely affecting the operation of the POTW or for violating any pretreatment standard or requirement, the department may, at any time on its own initiative or in response to a request received from an industrial user or POTW, determine that an industrial user is not a significant industrial user.

Significant industrial users must submit a treatment agreement which meets the following criteria:

1. The agreement must be on the treatment agreement form #542-3221,*pdf; and
   
   
2. Must identify and limit the monthly average and the daily maximum quantity of compatible and incompatible pollutants discharged to the disposal system and the variations in daily flow; and
   
   
3. Be signed and dated by the SIU and the owner of the disposal system accepting the wastewater; and
   
   
4. Provide that the quantities to be discharged to the disposal system must be in accordance with the applicable standards and requirements in 567-Chapter 62.

If the SIU is subject to Federal Pretreatment Standards, the limits in the TA must be at least as stringent as the applicable federal pretreatment standards. Categorical industries that are subject to a federal pretreatment standard must submit a Baseline Monitoring Report including discharge data. For SIUs that discharge Total Toxic Organics (TTOs), an alternative to routine TTO monitoring is the preparation of a toxic organic management plan (TOMP). This option is available to regulated industrial users in the Electroplating, Metal Finishing, and Electrical and Electronic Components categories.

New SIUs:
For new SIUs, a TA form must be submitted at least 180 days before a new SIU proposes to discharge into a wastewater disposal system. The owner of a wastewater disposal system shall notify the department by submitting a complete treatment agreement at least 10 days prior to making any commitment to accept waste from a proposed new SIU. However, the department may notify the owner that verification of the data in the treatment agreement may take longer than 10 days and advise that the owner should not enter into a commitment until the data is verified.

Existing SIUs:
An existing SIU must submit a new TA form 60 days in advance of a proposed expansion, production increase or process modification that may result in discharges of sewage, industrial waste, or other waste in excess of the discharge stated in the existing TA. An industry that would become an SIU as a result of a proposed expansion, production increase or process modification shall submit a TA form 60 days in advance of the proposed expansion, production increase or process modification. In addition, TA forms from SIUs are required as a part of the application for a permit to operate the wastewater disposal system receiving the wastes from the SIU.

Wastewater treatment plant construction or upgrade:
A treatment agreement form for each significant industrial user must be submitted with the facility plan or preliminary engineering report for the construction or modification of a wastewater disposal system.

Please contact an NPDES permit writer (NPDES Permits Staff Directory) with any questions regarding treatment agreements.