🚀 go-pugleaf

Alan Seideman (aneuman@netcom.com) wrote:



: 07/28/94 07:38 AM

: Has anyone knowledge or, leads for data about possible
: problems encountered by water treatment facilities and
: tetrachloroethylene, or pce. 

: I have heard recently that the
: use of pretreatment by carbon beds followed by aeration has
: not removed the pce but merely redeposited it about the
: perifery of the facility.  I believe there was such a
: problem in the Santa Barbara, Ca. area. 

: I know that various
: POTWs have prohibited the discharge of aqueous wastes
: containing this chemical, but, I'd like to know the reasons
: for such prohibitions.

If I remember correctly (and I might not because I had worked the 
midnight shift the night before), at a seminar last year at the San Jose
treatment facility, there was mention that preliminary data reveals that 
the chlororganic compounds in the effluent, in the presence of sunlight, 
may yield carcenogenic compounds. 

The situtation has been of more concern since POTWs have had to deal with 
nitrogen limits in their effluent. The inorganic nitrogen provides a food 
source for algae. The nitrogen, in combination with phosphorous, can cause 
significant algae blooms and therefore a increased oxygen demand upon the 
receiving waters.

Since most plants still use chlorine as a disinfectant, and the nitrogen 
compounds affect the disinfection process by the creation of mono, 
di or tri-chloramine compounds, there is concern about the presence of 
any chloroganics in the wastewater.
 
When you mention that the POTW's " have prohibited the discharge..." I 
assume that you are speaking about pretreatment from industrial 
dischargers TO the facility. New legislation as well as more restrictions 
in POTW's NPDES permits have required the source control folks to be a 
bit more diligent in their efforts to protect the receiving waters by 
starting at the source. 

Hopefully someone else (who was awake...) can give you more specifics on 
the compound.

Occasionally, carbon beds are used to adsorb and thus remove organic 
gases (and some inorganic gases like hydrogen sulfide) held in suspension 
in the wastewater flowstream.
-- 
Ken Navarre
kjn@netcom.com