All posts tagged POTW

Posted: September 29, 2014

WASHINGTON – The U.S. Environmental Protection Agency (EPA) today proposed standards under the Clean Water Act to help cut discharges of dental amalgam to the environment. Amalgam is a mixture of mercury and other metals that dentists use to fill cavities. Mercury is discharged when dentists remove old fillings or remove excess amalgam when placing a new filling.

Studies show about half the mercury that enters Publicly Owned Treatment Works (POTWs) comes from dental offices. Mercury from amalgam can then make its way into the environment in a number of ways, including through discharge to water bodies. Contact with some microorganisms can help create methylmercury, a highly toxic form of mercury that builds up in fish, shellfish and fish-eating animals. Fish and shellfish are the main sources of human exposure to methylmercury.

In response, many states and localities have implemented amalgam discharge-cutting programs requiring amalgam separators and other Best Management Practices in dentist offices. The American Dental Association (ADA) also recommends separators and other Best Management Practices for amalgam.

EPA expects compliance with this proposed rule would cut metal discharge to POTWs, half of it from mercury, by at least 8.8 tons a year.
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Posted: July 1, 2014
On June 30, 2014, the Water Permits Divison in EPA’s Office of Wastewater Management posted a set of Frequently Asked Questions (FAQs) to the NPDES web site: http://cfpub.epa.gov/npdes/pathogenfaq.cfm

This set of FAQs provides an overview of NPDES permitting applicable to continuous dischargers (such as Publicly Owned Treatment Works) based on water quality standards for pathogens and pathogen indicators associated with fecal contamination.

These FAQs answer questions to help EPA, state, tribal and territorial NPDES permit writers understand implications of changes to state water quality standards based on the 2012 Recreational Water Quality Criteria (RWQC), published November 29, 2012.

The 2012 RWQC recommendations are for two bacterial indicators of fecal contamination – enterococci and E. coli. Section 304(a)(9) of the Clean Water Act directed EPA to publish new or revised water quality criteria recommendations for pathogens and pathogen indicators for the purpose of protecting human health. A pathogen indicator, as defined in section 502(23) of the CWA, is “a substance that indicates the potential for human infectious disease.” Most strains of enterococci and E. coli do not cause human illness (that is, they are not human pathogens); rather, they indicate the presence of fecal contamination.

If you have any questions regarding the FAQs, please contact David Hair [hair.david@epa.gov] at 202-564-2287.