Dental facilities

On June 9, 2017, the US EPA finalized the Dental Effluent Guidelines. These guidelines require facilities to install and maintain an amalgam separator, which removes mercury-containing amalgam from the wastewater process prior to discharge to the sanitary sewer.

In accordance with this EPA ruling, EBMUD requires dental facilities to complete a one-time Dental Facility Compliance Report due no later than July 14, 2020. The Dental Facility Compliance Report is available below. 

Studies have shown that about one third of the mercury discharged to EBMUD's wastewater treatment plant is from dental practices. EBMUD works with dental facilities to remove mercury-containing amalgam from wastewater discharges.

Frequently asked questions

Mercury is one of the 12 toxic pollutants identified by the U.S. EPA that is impairing Central San Francisco Bay, and is listed in Section 303 (d) list of the Clean Water Act. Mercury bioaccumulates and persists in the environment. Currently, fish consumption advisories are issued in 41 States. The San Francisco Bay is included on the fish consumption advisory list.

Studies have shown that approximately one third of the mercury discharged to EBMUD's wastewater treatment plant is from dental practices and that mercury cannot be removed through the wastewater treatment process. The environmental and public health risks associated with mercury contamination have spurred the Federal EPA to issue the Dental Effluent Guidelines in 2017 and codified in 40 CFR 411

Following the Federal EPA ruling issued on June 9, 2017 all dental facilities must:

  1. Install and maintain an amalgam separator and
  2. Complete and return the one time Dental Facility Compliance Report and return it to EBMUD

The deadlines for meeting compliance are July 14, 2020 for dental facilities that were open before the July 14, 2017.

Dental facilities that opened after July 14, 2017 have 90 days to comply with the above rules. 

Even if your dental facility does not actively remove amalgam, you still need to complete a Dental Facility Compliance Form. Practices specializing in orthodontics, oral pathology/oral medicine, periodontics, prosthodontics, oral & maxillofacial surgery/radiology, and mobile dentists must also complete the form but may skip sections B-D. 

The Dental Facility Compliance Form must be completed by the current practicing dentist at each facility. So if you just took over a dental practices then you will need to complete your own form within 90 days of acquiring the practice.

Red bag waste may require incineration. Incinerated mercury volatilizes and becomes an air pollutant. It also may eventually end up in surface water.

If the amalgam is disposed of with other garbage, the mercury may end up in the landfill leachate, which may eventually contaminate groundwater or surface water.

Contact your local dental association for information on amalgam recycling options.

Not all of the scrap amalgam and particulates are captured by the chair-side traps and vacuum filters. Grinding, drilling, and polishing of amalgam fillings may result in the production of fine particulate matter that passes through the chair-side traps and vacuum filters (Nimmo et al., 1990, Brune et al., 1980). The residual particulates remain in the wastewater discharged to the sanitary sewer.

An additional source of mercury is wastewater from instrument washing, and chair-side trap and vacuum filter cleaning. This wastestream may not be managed by a device designed to capture amalgam.

A practical type of treatment is amalgam separators used to remove amalgam waste and particulates from wastewater prior to discharging to the sanitary sewer (see the Naval Dental Research Institute's website for the American Dental Association's evaluation of available amalgam separators).

Studies (Arenholt-Bindslev and Larsen, 1996, MASCO) have shown that significant amounts of amalgam particulates can accumulate in dental office plumbing lines. When biomass build-up sloughs off the inside of the pipe, mercury ends up in the sanitary wastestream. A study in Sweden found as much as 30 pounds (lbs) of waste amalgam (~15 lbs of mercury) in the plumbing of a large dental office.

Cleaning or replacing the p-trap can be a cost-effective means of removing the build-up of amalgam that may end up in the sanitary sewer system. Even if a dental practice has an up-to-date amalgam management system, mercury may still be present in the building's plumbing from years past.