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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 questionnaire. 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 ProgramMWRD_Dental-Amalgam-Control-Program_logo_circle_FINAL.png
On June 14, 2017, the EPA issued a final rule regarding the handling of dental amalgam waste at 40 CFR Part 441, Effluent Limitations Guidelines and Standards for the Dental Category, with an effective date of July 14, 2017. The final rule requires dental offices to use a qualifying amalgam separator and comply with industry best management practices to reduce amalgam waste.

Effective July 2, 2018, the Metro District's Dental Amalgam Control Program’s Rules and Regulations were revised to better reflect this final federal ruling while continuing to meet our own local limits.  The Metro District’s program Rules and Regulations meet the requirements of the federal rule and are in some areas more stringent than the federal requirements.
These new regulations now allow a broader range for exemption status.  Businesses may claim exemption status if any of the following apply:

1.  A business exclusively practices:
Oral pathology            Oral and maxillofacial radiology                 Oral and maxillofacial surgery
     Orthodontics               Periodontics        Prosthodontics                 Mobile dentistry

2.  Or, the dental facility does not place any amalgam, and whose removal of teeth with amalgam comprises
less than 5 percent of the dental facility’s business

One-Time Compliance Report Required
With a deadline of October 12, 2020, all existing dental sources (both exempt and non-exempt) must complete a One-Time Compliance Report and, if non-exempt, also must submit with this report a copy of your Operations and Maintenance Plan.  All One-Time Compliance Reports must be signed by an Authorized Representative of the facility. (Links to all forms are available in the Resources column to the left of this screen.) 
Please complete the report that most accurately fits your dental operations, and mail it to the Metro District at 6450 York Street, Denver, CO 80229.  The Metro District reserves the right to review and/or deny any exemption claims that do not match previously identified operations at your facility.  Information may also be verified via an on-site inspection by our staff.
For all new source businesses, those who opened on July 14, 2017, or later, the Regulations went into effect immediately and are enforceable under Section 6.28 of the Metro District’s Rules and Regulations.  These businesses must also submit the One-Time Compliance Report within 90 days of initial discharge.
Be advised, failure to submit the One-Time Compliance Report by the October 12, 2020, deadline, may result in enforcement action(s) that may include the assessment of penalties and/or suspension or termination of sanitary sewer service and/or other administrative or legal actions as provided for in Section 6.28 of the Metro District’s Rules and Regulations.
Best Management Practices
All dental facilities are required to comply with best management practices and requirements to operate and maintain an amalgam separator according to its manufacturer's recommendations, as required by 40 CFR Part 441 and the Metro District’s Rules and Regulations, Section 6.16.1 – Dental Amalgam Control Program. (Links are available in the Resources column to the left of this screen.) 
Additional Information
For additional information about the Metro District’s Dental Amalgam Control Program, contact:
Amalgam Control Program Investigator: 
Suzanne Renter     303-286-3128

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 →