As you may have read or heard, the EPA is proposing a mandate for the regulation of dental amalgam waste from existing and new dental practices. This mandate will impose pretreatment standards on dental offices that are similar to CIU standards.
Research has shown that dental offices are the main source of mercury discharges to POTW’s as dental amalgam is made up of 50% mercury. The amalgam discharge accounts for an estimated 50% of the mercury that flows into our nation’s POTWs and contains three times as much mercury as the next pollutant source. It is also estimated that dental offices discharge approximately 4.4 tons of mercury each year. Of the over 120,000 dental offices in the United States, almost all of these discharge to a POTW.
The simplest solution for removing mercury from the waste stream is to remove it in a concentrated and easy to handle form, hence the EPA is proposing that Amalgam Separators be installed. These separators act like traps installed in-line with the drain so that the heavy particles fall out of the waste stream and settle at the bottom of the trap. Since 2007, the American Dental Association has recommended separators as part of its Best Management Practices and yet only about 1/3 of US dentists have separators installed. Amalgam Separators are considered the most effective Pollution Prevention Strategy for mercury and the cost to install one is approximately $700 – $1000. The cost equates to $0.50 per patient a year and yet voluntary efforts to get dentists to install separators have proven unsuccessful. This failure to install separators voluntarily is the reason this mandate for dental regulations has come about. This drive for new regulations has led to a new classification of CIU called DIU (Dental Industrial User). These users are not subject to the oversight requirements for SIUs and are not considered a SIU. The EPA proposes to allow Control Authorities to focus the oversight efforts on dental offices that fail to meet compliance requirements of the DIU category.
If this proposed mandate passes, the Control Authority will be required to evaluate at least once per year whether an IU previously determined to be a DIU still meets the criteria for treatment as a DIU under 40 CFR 441.60. This evaluation will primarily involve the verification that the certification has been submitted by the dental office documenting continued eligibility for DIU status. If it fails to provide any required report within 45 days of the due date or if the Control Authority elects to inspect the facility and find the facility is not in compliance with 40 CFR 441.60, the Control Authority must initiate enforcement in accordance with its approved Pretreatment Program to return the dental discharger into comopliance. After enforcement, the Control Authority would need to verify and find through an inspection that the dental discharger has returned to full compliance with the criteria set forth in 40 CFR 441.60. If within 90 days, the Control Authority inspects, verifies, and finds that the dental discharger has returned to full compliance with the 40 CFR 441.60, then the dental discharger would remain a DIU. If they have not returned to compliance within 90 days, the Control Authority could no longer treat the dental discharger as a DIU and they would become SIU. This means you would then have to issue them a permit, inspect them once a year, sample them once a year, and review the need for a slug control plan. Also, if this mandate passes, it will require changes to the POTWs sewer use ordinace.
With this mandate in place, the EPA expects that compliance with this rule would reduce the discharge of metals to POTWs by at least 8.8 tons per year.