The United States Enivonmental 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 submit a one-time compliance report to their pretreatment Control Authority. For dental offices that discharge wastewater to MSD, MSD is their pretreatment Control Authority. The one-time compliance report, with instructions, can be downloaded here.
The completed report should be mailed to:
Industrial Pretreatment Manager
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.