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Pretreatment of Wastewater (Industrial Users) Compliance Monitoring

CWA Topics

Publicly Owned Treatment Works (POTWs) collect wastewater from homes, commercial buildings and industrial facilities and transport it via a series of pipes, known as a collection system, to a treatment plant. The POTW removes harmful organisms and other contaminants from the sewage so it can be discharged safely into a receiving stream. Generally, POTWs are designed to treat domestic sewage only. However, POTWs also receive wastewater from some industrial (non-domestic) users.

The General Pretreatment Regulations establish responsibilities of federal, state and local government, industry and the public to implement Pretreatment Standards to control pollutants from the industrial users which may pass through or interfere with POTW treatment processes or which may contaminate sewage sludge. The POTW acts as the control authority for these industrial users and monitors the wastewater they discharge to determine whether they are in compliance with the pretreatment standards.

Compliance Monitoring

EPA conducts both inspections and audits of the Control Authority, normally a POTW, to assess the effectiveness of the pretreatment program. Pretreatment audits are designed as a comprehensive review of all facets of the Control Authority's pretreatment program. The audit addresses all of the items covered in a pretreatment inspection, but in greater detail.

Pretreatment inspections involve:

Details on the pretreatment program can be found in Chapter 9 of the NPDES Compliance Inspection Manual.

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