Memo to the project file

From: Damon Highsmith

Date: 09/23/2014

Re: Date by which facilities opting to continue operating amalgam separators that achieve less than

99 .0 % removal must have installed a separator.

This proposed rule would establish a pretreatment standard that would require removal of at least 99.0% of total mercury from amalgam discharges and BMPs. One way affected dental offices would be able to meet the standard would be to use, and properly operate and maintain, a dental amalgam separator certified to achieve at least 99.0% reduction of total mercury according to the 2008 ISO 11143 standard, to perform certain BMPs, and to certify to this effect.

While the proposed rule does not require the use of an amalgam separator to meet the numeric standard, EPA expects that most, if not all dentists that place or remove amalgam would use this widely available technology to comply with the proposed numeric standard. EPA expects dentists will choose
to instal l and operate an amalgam separator because of the nature of dental offices, the variability of the flows and resulting waste streams, and the difficulty in obtaining a sample that represents only dental amalgam discharges. Moreover, amalgam separators are an easy to use, low cost technology. Dental offices that elect to not use an amalgam separator must meet the proposed numeric limit and would be subject to the oversight and compliance requirements for indirect discharges subject to national pretreatment requirements.

In selecting an amalgam separator that meets the requirements of today’s proposed pretreatment standards, dentists would verify that the amalgam separator is compliant with the 2008 ISO 11143 standard and meets the design specifications of the proposed regulation for their configuration. Once selected and installed, EPA expects dentists will operate and maintain the separator following all manufacturer’s instructions and conduct inspections at least monthly to ensure all features are
functi onal.

EPA does not want to penalize existing dental offices or institutional dental facilities that have already installed amalgam separators either voluntarily or to comply with state or local requirements. EPA recognizes that these offices may currentl y have amalgam separators in place that are certified to a removal rate slightly less than this proposed standard. For example, some states require dental offices to employ amalgam separators that are certified to remove 95% total mercury. EPA does not p ropose a rule that would require existing separators that still have a remaining useful life to be retrofitted with new separators, both because of the additional costs incurred by dental facilities that moved ahead of EPA’s proposed requirements to instal l a treatment technology and because of the additional solid waste that would be generated by disposal of the existing separators. Therefore, EPA is proposing that, as long as they continue to properly operate and maintain existing separators, comply with BMPs, and comply with recordkeeping requirements, these facilities would be considered in compliance with the numeric standard until ten years from the effective date of the final rule. EPA selected ten years because it appears to be a conservative estima te of the useful life of the existing equipment. However, if prior to that time, the currently installed separator needs to be replaced, these facilities would need to install and operate an amalgam separator that meets a removal efficiency of 99.0%.EPA decided that facilities that have not installed separators as of the date of publication of the proposed rule in the Federal Register and choose to do so to comply, in part, with the proposed rule would be required to install amalgam separators that achie ve at least 99.0% reduction of total mercury according to the 2008 ISO 11143 standard . Choosing the date of publication of the proposed rule in the
Fede ral Register as the cutoff date takes into account those facilities that have installed amalgam
separato rs and prevents them from having to replace their amalgam separators, while avoiding an unintended incentive for additional facilities to select amalgam separators that achieve less than the 99.0% reduction of total mercury that is included in the proposed rule.