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Industrial Pretreatment Program

​​The U.S. Congress created the national EPA-mandated Pretreatment program in 1972 to protect the nation's wastewater treatment plants and waterways from discharges of toxic and other pollutants. “Pretreatment” refers to the requirement that industries discharging pollutants treat their wastewaters before discharging to municipal sewer systems. Objectives of our program are to:
  • Protect the District's treatment plant and South Platte River from non-domestic pollutants that could pass through the plant if untreated, and ensure that the Metro District's wastewater and biosolids remain of high quality.
  • Protect Metro District employees and the general public from potentially harmful chemicals.
  • Enable the Metro District to comply with all applicable environmental permits, laws, and regulations.

What Industries are Regulated by this Program?

All businesses, including industrial, commercial and governmental establishments, that discharge anything other than normal sanitary wastewater are subject to the requirements of the Pretreatment Program, and should complete and submit an Industrial Waste questionaire. For most businesses, this simply means they cannot discharge anything that will adversely affect the wastewater system, its workers, or the resulting effluent or biosolids. See Section 6 of the Metro District regulations.

Businesses with a reasonable potential to violate pretreatment standards and requirements or who perform a process deemed by EPA as a “categorical process”, have additional requirements. We classify these businesses as Significant Industrial Users (SIUs) and require them to obtain industrial discharge permits in order to discharge to the sewer system. Examples include

  • Electroplating
  • Metal finishing
  • Nonferrous metals forming
  • Battery manufacturing

Permits contain specific limits on the industrial pollutants that are present in an industry's discharge. Permits also contain monitoring and reporting requirements with which the industry must comply if it is to continue discharging into the sewer system.

Dental Amalgam Control Program

In August 2014, the Metro District established a Dental Amalgam Control Program to meet the anticipated mercury limitation in its next Colorado Discharge Permit System permit.  The District’s Dental Amalgam Control Program requires dental facilities that discharge wastewater generated from the placement or removal of dental amalgam to comply with the requirements to install an amalgam separator and implement best management practices (BMPs). In July 2017, the Federal Effluent Limitations Guidelines and Standards for the Dental Category also became effective. New and relocated facilities must comply as follows:

  • Prior to discharge from a new business (opened after July 2017), install an amalgam separator. A signed copy of the Amalgam Separator Installation Certification form must be received by the District within
    90 days of installation.
  • Within 90 days of starting business, submit a signed copy of the BMP Certification form.
Copies of all the required forms may be found on the left of this screen, including training materials, the initial BMP Certification form, initial Amalgam Separator Installation Certification form, Metro District’s Dental Amalgam Control Program Advisor, and applicable sections of the District’s Rules and Regulations Governing the Operation, Use and Services of the System (Rules and Regulations). 
If a dentist office does not place or remove amalgam and/or teeth containing amalgam and would like to apply for a waiver of this program, it may submit a brief summary of the activities that take place at its facility and how it ensures no amalgam work is conducted.  If the Metro District concurs and grants a waiver, the dentist office will be required to annually certify to “no amalgam work” at its facility.
All existing dental facilities placing or removing any amalgam are required to certify annually to the ongoing compliance with their amalgam separator maintenance, operations and maintenance plan, and BMPs.  These facilities will be inspected every 3 to 5 years. If certification statements are not submitted, the Metro District will inspect the facility to determine compliance.  The District also may conduct site inspections of the facility to verify any submitted information.

What Happens if a Facility Fails to Comply?

Any non-domestic discharger who fails to comply with pretreatment program standards and requirements faces the possibility of serious enforcement actions, including monetary penalties and termination of service. Our Pretreatment Enforcement Management System details the our policies and procedures for identifying, documenting, and responding to Pretreatment Program violations.
Submit an inquiry for more details about our Pretreatment Program →