The Narragansett Bay Commission VA `r ~

One Service Road Chairman

-2 t bLtVinct J. Mesolella

Providence, Rhode Island 02905

Raymond J. Marshall, P.E.

401 • 461 • 8848

Executive Director 401 • 461 • 6540 FAX

'I'I'Y (RI RELAY OPERATOR) 711 JAN 0 2 20C8

http:/iwww.narrabay .com

~nsett B'~~

December 27, 2007

Water Docket

Environmental Protection Agency

Mailcode 4203M

1200 Pennsylvania Avenue, NW

Washington, DC 20460

RE: Docket ID No. EPA-HQ-OW-2006-0771

Dear Sir/Madam :

The Narragansett Bay Commission (NBC) owns and operates the two largest Publicly

Owned Wastewater Treatment Works (POTW) located in the State of Rhode Island. One

POTW, the Field's Point WWTF is located in Providence and the other is located at

Bucklin Point in East Providence . The NBC has thoroughly reviewed the Preliminary

2008 Effluent Guidelines Program Plan and would like to thank the USEPA for providing

the opportunity to comment on this important plan.

Based upon our review, the NBC does not recommend that the EPA expend valuable

resources to develop new federal catego rical regulations for indirect dischargers. The

NBC, like other POTWs with approved Pretreatment Programs, has extensive knowledge

and experience controlling the discharge of toxics from industrial and commercial

sources. Technologically developed local limits, along with an enforceable sewer use

ordinance, are all the tools that are necessary for the NBC's Pretreatment Program to

protect our wastewater facilities, the receiving waters of Narragansett Bay, public health

and the environment .

The NBC would like to further comment on the Effluent Guideline proposed for

controlling dental mercury. In 2003, the NBC developed a Best Management Practices

document for the Management of Waste Dental Amalgam (BMP) and the NBC

implemented a BMP Dental Program in 2004. The NBC worked with the R.I. Dental

Association to develop this program . A copy of the BMP is attached to this letter for

your information. The BMP provides facilities, including dental offices, dental clinics

and hospitals, that have the potential to discharge mercury containing dental amalgam to

the sewer system two options to control the discharge of mercury to the sewer system . The first option allows the facility to install an amalgam separator that has a separation

efficiency of 99% according to ISO 11143 standards . Under this option the permitted user

is not required to routinely sample the waste stream . The second option requires the user

to routinely sample their discharge and achieve compli ance with the local mercury

discharge limitation established to protect the treatment facility and the environment

.

DEC 2 7 2OC' 8

a dean Gay today a denrr hay to(ja)a clean bay toda) a dean hay toda)a deare ba)toda)a rltart Ga} toda}a dean Gaq today a rlrarr Ga}toda)a clean ha} today
p. 2

In addition to the two options, there are mandatory Best Management Practices that must

be followed by this class of users. These include the following :

➢ installation of dental chair side traps and their maintenance,

➢ maintenance of vacuum pump filters ,

➢ storage, management and disposal of scrap amalgam,

➢ use of only approved line cleaners,

➢ specific requirements for sinks located in operatories,

➢ annual certification submittal requirements,

➢ record keeping requirements, an d

➢ training of dental staff in waste management and spill response .

In addition the BMP document provides information about pollution prevention and

hazardous waste management. All of the facilities in the NBC's two districts opted to

install amalgam separators in lieu of performing routine effluent monito ring. These

BMPs are written into Wastewater Discharge Permits issued to each facility performing

dental operations. By implementing the BMP program, the NBC has seen a great

reduction in the influent mercury loading to both NBC Wastewater Treatment plants . In

fact within the first six months of implementing the program the NBC Field's Point plant

realized an 18% influent mercury loading reduction and the Bucklin Point plant achieved

a 23% reduction in mercury loading. The following table of annual influent loadings

clearly demonstrates the success of the NBC Dental Mercury BMP Program :

Year Field's Point (Ibs) Bucklin Point (Ibs)

2003 16.0 6.5

2004 13.1 5.4

2005 13.3 5.6

2006 10.8 4.5

Overall % Reduction 32.5% 30.8%

The NBC Dental Mercury Control BMP Program has been so successful that the Rhode

Island Department of Environmental Management has implemented the NBC program as

a mandatory requirement throughout the state . To summarize, the NBC believes that

Publicly Owned Wastewater Treatment Works are effective at controlling the discharge

of mercury to the sewer system from dental facilities and that imposing new or additional

categorical standards are not necessary for indirect dischargers controlled by approved

Pretreatment Programs. Thank you for providing the Narragansett Bay Commission the

opportunity to comment on the Preliminary 2008 Effluent Guidelines Program Plan . If

you have any questions or need any additional information, please feel free to contact me

at 401-461-8848 ext. 470.

Sincerely,

Thomas P. Uva

Director of Planning, Policy & Regulation

Cc : Raymond J. Marshall, P.E. - NBC

Kerry M. Britt - NBC

Chris Hornback - NACWA