Industrial Pretreatment Program

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In 1972, the United States Congress passed the "Water Pollution Control Act" with the purpose to "restore and maintain" the quality of our nation's water. The "Water Pollution Control Act" was amended in 1977 and re-titled the "Clean Water Act." As amended, the "Clean Water Act" includes requirements limiting the level of pollutants that industries are allowed to discharge into sanitary sewer systems. Within the Clean Water Act, the United States Congress established the Environmental Protection Agency (EPA).

In 1978, the EPA established the "General Pretreatment Program Regulations." These regulations and the subsequent amendments required Wastewater Treatment Plant nationwide to operate EPA-approved Pretreatment Programs.

The objective of the National Pretreatment Program is to control the industrial discharge wastes that could interfere with treatment processes, which could result in reduced treatment efficiencies; and to prevent pollutants from passing through the treatment works, that would degrade the receiving waters. The National Industrial Pretreatment Regulations require that industries pre-treat their process wastewater to remove excess pollutants, prior to discharging to the Wastewater Treatment Plant. The federal Resource Conservation and Recovery Act (RCRA) regulate specific waste types as hazardous waste. The RCRA regulations are published in volume 40, Part 260 of the "Code of Federal Regulation". Organizations that generate, store, ortransport hazardous waste are required to notify the EPA of their activity and obtain an identification number. If you need more information, please visit the Environmental Protection Agency's web site.


The Industrial Pretreatment Program (IPP) regulates industries in two ways. Specific types of processes are regulated by federal categorical standards and all industries are also regulated by City discharge limits that are specific for the City's Wastewater Treatment Facility. The federal categorical standards specify the quantity or concentration of pollutants, or pollutant property, which may be discharged to a wastewater treatment facility (WWTF) by an industry in specific industrial categories. The "General Pretreatment Regulations" are published in volume 40, Part 403 of the "Code of Federal Regulation". The City Municipal Code under Chapter 13.32 "Sewer Use Regulation" set forth uniform limits and requirements for direct and indirect contributors to the wastewater collection and treatment system of the City.


In 1983, the City's IPP was mandated as a provision of the National Pollutant Discharge Elimination System (NPDES), permit number- CO 0023078 and regulated through the U.S.E.P.A. Region VIII and Colorado Department of Public Health & Environment (CDPH&E). The City's IPP has gone through numerous changes to comply with new requirements and regulations over the years. The goals of the City's IPP are:
  • To enrich the health and economic welfare of the community are of the utmost importance.
  • To protect the receiving stream (Coal Creek) from pass through of toxic chemicals and heavy metals.
  • To prevent interference with the City Wastewater Treatment Plant's treatment process.
  • To maintain non-interfering, biological treatable influent to create and maintain high quality effluent, reclaimed water and Class "A" biosolids.
  • To protect our employees from hazardous substances that could be discharged from an industrial setting.

The City requires all current and future commercial and/or industrial users of the City's Wastewater Treatment Plant to complete and return the Wastewater Classification Survey form prior to discharging wastewater to the City Sewer System. The survey form is designed to provide enough information for the City to determine if a complete Wastewater Discharge Permit Application will be required. These forms are available electronically in a PDF format.

Presently, the City's IPP consists of an Industrial Pretreatment Coordinator, who is also the Wastewater Plant Superintendent and a Pretreatment Specialist. Their primary duties consist of regulating and monitoring all industrial and commercial businesses located within the city limits of Louisville and to assist those industries and businesses whenever necessary with compliance issues or questions related to the City's IPP. The following procedures are used to ensure the City's IPP goals and requirements are met:

1. Classification of Non-Residential Users
  • Review wastewater classification survey submittals for the purpose of identifying possible critical users.
  • Review non residential building permit applications for non residential users moving into new facilities and non residential users expanding facilities.
2. Issuance of discharge permits to significant industries
  • Promotes Industrial User (IU) awareness of the sewer use ordinance, discharge limitations, and user responsibility.
  • Initiates frequency of self monitoring wastewater discharge requirement.
  • Establishes a method of violation detection, reporting, and pollution prevention
  • Enforces pretreatment where needed.
  • Assists IU to comply with EPA, CDPH&E and City Sewer Use requirements.
3. Industrial User discharge monitoring

  • Receive and evaluate compliance reports from the IU.
  • Monitor the industries for compliance with their wastewater discharge permits.
  • Establishes additional sampling requirements where necessary.
  • Ensure IU complies with USEPA, CDPH&E and City Sewer Use requirements.

4. Compliance tracking

  • Identifies compliance, non-compliance, and significant non-compliance of discharge permit.
  • Determines which type of enforcement action to be taken.
  • Measures effectiveness of enforcement action.
  • Complies with USEPA, CDPH&E and City Sewer Use requirements.

5. Implement the City's IPP Enforcement Response Guide
  • Establishes a penalty for non-compliance.
  • Expedites progress toward compliance.
  • Shortens duration of non-compliance.
  • Complies with USEPA, CDPH&E and City Sewer Use requirements.
6. Report writing
  • Documents pretreatment actions taken during previous reporting period.
  • Documents changes in local industrial base.
  • Documents changes in pretreatment program to inform the public and industry of changes in local, state or federal regulations.
  • Complies with USEPA, CDPH&E and City Sewer Use requirements.
7. Monitoring WWTF influent, effluent, reclaim water and biosolids per National Pollutants Discharge Elimination Systems (NPDES) Permits.
  • Measures quality of plant influent, effluent, reclaim water and biosolids.
  • Measures effectiveness of plant operations.
  • Measures overall effectiveness of industrial pretreatment program.
  • Complies with USEPA, CDPH&E and City Sewer Use requirements.

If you would like further information about this program you may call 303.335.4779. 

Emergency and Non-Emergency Notification

For accidental or slug discharge to sewer system, please call:
303.441.4444 for emergency situations
303.335.4667 for non emergencies

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