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Re: Pretreatment guidance for priority and other chemicals accepted at wastewater treatment plants



All,
A wastewater treatment plant's ability to accept wastes is *individual*
and *not generic.* You must consult the specific plant.  Variables
include not only the plant's treatment processes, but also the effluent
limits to the receiving water (site-specific), the other discharges to
the plant, and the impairments of the receiving water (which may be
about to cause new effluent limits to be placed on wastewater treatment
plants; such limits may significantly reduce effluent limits).

Mid-sized and larger wastewater treatment plants (I believe more than 5
million gallons per day) have "local discharge limits" that are set by
the plant.  Such plants also issue permits for discharge and made
determinations about the allowability of any industrial waste
discharge.  The program that does this work is called the "pretreatment
program".  That program should be contacted directly for discharge
information; if you can't identify the Pretreatment Coordinator, call
the plant manager.  If you are working on a statewide issue, you can
usually obtain information about the state's major issues from the state
environmental agency's pretreatment oversight program (if that has been
delegated to the state) or the pretreatment group in the USEPA Regional
office's water division.

Also, it is very important to recognize that any pollutant you put in
the sewer system eventually goes somewhere in the environment.  A few
pollutants (e.g., nutrients) are actually destroyed in a sewage
treatment plant, but many toxic pollutants (e.g., benzene, metals)
simply pass through the plant and wind up in one of the plant's releases
(water, to river, estuary, or ocean; sludge, to field or landfill; air
emissions).  (If the plant has an incinerator, the sludge is converted
to ash and some pollutants are destroyed, but others are created and
many pollutants (e.g., mercury) are emitted to air by sewage sludge
incinerators, so they are not a great environmental technology either.) 
I strongly discourage use of the sewer as a waste disposal method,
because of the inevitable release of the pollutant to the environment;
unfortunately, sewer disposal is still cheap (real environmental costs
not paid) and much of the pollutant releases are still uncontrolled at
many plants (e.g., air emissions of benzene may not be regulated).

Kelly Moran
TDC Environmental
(and a former pretreatment program staffer)

Cindy McComas wrote:
> 
> I am looking for a reference document or website for pretreatment
> requirements or guidance for a wastewater treatment plant's ability to
> accept and treat certain chemicals such as benzene or other baddies, which
> might provide limits based on the type of wastewater treatment design, such
> as trickling filter, activated sludge, etc.  Any thoughts?  Thanks!
> 
> *********************************
> Cindy McComas, Director
> MnTAP
> University of Minnesota Gateway
> 200 Oak Street SE, Suite 350
> Minneapolis, MN  55455-2008
> 612-624-4678
> 612-624-3370 (fax)
> mccom003@tc.umn.edu
> http://www.mntap.umn.edu