The United States Environmental Protection Agency (EPA) has developed regulations to reduce discharges of mercury from dental offices into sewer systems. The Dental Office Category regulation is contained in 40 CFR Part 441.
Dental offices discharge mercury present in amalgam used for fillings. Amalgam separators are a practical, affordable, and readily available technology for capturing mercury and other metals before they are discharged into sewers that drain to treatment plants. Once captured by a separator, mercury can be recycled.
- Dental offices that place or remove amalgam must operate and maintain an amalgam separator and must not discharge scrap amalgam or use certain kinds of line cleaners. These offices must operate and maintain an amalgam separator, must not discharge scrap amalgam or use certain kinds of line cleaners, and must submit a one-time compliance report to their pretreatment Control Authority,
- For dental offices that do not place or remove amalgam, they need only submit a one-time certification.
- For dental offices that discharge wastewater to MSD, MSD is their pretreatment Control Authority.
- Dental offices that were in existence prior to when the rule was issued, July 14, 2017, must be in compliance with the standards by July 14, 2020, and submit a one-time compliance report to MSD certifying such by October 12, 2020.
- Dental dischargers whose first discharge occurs after July 14, 2017 must be in compliance with the standards immediately and submit a one-time compliance report to MSD certifying such within 90 days after first discharge to a POTW.
- If a dental office that was in existence prior to July 14, 2017 transfers ownership, the new owner must submit a new one-time compliance report to MSD by October 12, 2020, or if the transfer occurs after July 15, 2020, no later than 90 days after the transfer.
- If a dental office that began operations after July 14, 2017 transfers ownership, the new owner must submit a new one-time compliance report to MSD no later than 90 days after the transfer.
The one-time compliance report, with instructions, can be downloaded here: One-Time Compliance Report for Dental Dischargers.pdf
The completed report should be mailed to:
Industrial Pretreatment Program
Metropolitan St. Louis Sewer District
Division of Environmental Compliance
10 East Grand Ave.
St. Louis, MO 63147
EPA maintains a website with detailed information regarding the Dental Effluent Guidelines, including a section on frequently asked questions. The Fact Sheet and FAQs are easily readable, and may answer many if not all of your questions regarding the Dental Office Category regulation.
The American Dental Association also maintains a very helpful website regarding the amalgam and this rule that provides additional practical information. It provides additional information from a dental practice perspective.