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RE: Examples of reuse or recycling of sulfuric acid or solvents


*	One local wire mill supplies (or at least used to supply) a
publically owned wastewater treatment plant with waste sulfuric acid to
replace the use of ferric chloride in the treatment process.  I THINK the
ferric chloride, and/or sulfuric acid, are used for phosphate removal.

*	A local metal finisher (electroplater) uses his waste caustic to
neutralize waste acid, or vice versa, in his captive pre-treatment system..

*	Two other possibilities come to mind for re-use of sulfuric
acid...pending the level of contamination (I really think anyone wanting the
waste acid for uses other than wastewater treatment would be very concerned
about contaminants already in the waste):
	1) waste acid could be used as a neutralizing agent in an air
scrubber system, and
	2) the waste acid could be used for cleaning reaction vessels and/or
transfer lines in manufacturing plants using batch reactors (or used as a
caustic neutralizing agent if caustic is initially used for cleaning).
	One plant of which I am aware maintains a large tank of caustic
(24,000 gallons of NaOH) for cleaning reactor vessels.  Each caustic
cleaning is followed by an acid neutralizing step.  (The caustic is pumped
into reactors for cleaning then back to the main tank.  The acid is used to
neutralize anything remaining in the reactor prior to discharge.)



-----Original Message-----
From: Katz.John@epamail.epa.gov [mailto:Katz.John@epamail.epa.gov]
Sent: Tuesday, February 20, 2001 6:59 PM
To: P2@ucsd.edu; p2tech@great-lakes.net
Subject: Examples of reuse or recycling of sulfuric acid or solvents

Forward from a colleague here in Region 9. You can respond to me or to him
directly at jones.davidb@epa.gov

John Katz
P2 Coordinator
EPA Region 9

----- Forwarded by John Katz/R9/USEPA/US on 02/20/2001 04:02 PM -----

                    DavidB Jones

                                         To:     John Katz/R9/USEPA/US@EPA

                    02/20/2001           cc:

                    03:58 PM             Subject:     Examples of reuse or
recycling of       
                                         sulfuric acid or solvents


     I am participating in a training session for the semiconductor,
Printed Wire Board, and electronics industry which will be discussing
cleaner production techniques as well as dealing with hazardous wastes that
are apparently stacking up in drums with limited disposal alternatives.
Rick Reibstein from Region 1 will be a co-presenter.  We are going to
fashion our presentation going right down the pollution prevention
hierarchy, starting with pollution prevention, waste reduction, and on-site
recycling.  I am going to cover off-site reuse, recycling, and disposal
options (the lower end of the ladder).

      What I would like to do is give some examples of how acids
(particularly sulfuric acid), solvents, or metal hydroxide sludges (RCRA
F006 sludge in this country) are being reused or recycled in this country
(examples are not limited to this industry sector)  Based on my experience
in this sector, I know that some F006 sludge is going to copper smelters,
that some acids are being used as feedstock to replace virgin acids in some
manufacturing processes, and that many solvents are being distilled (at a
RCRA TSD facility) or burned for BTU value. Therefore what I would like to
find out is:

1.   Examples of how acids (particularly sulfuric acid) is being reused or

2.  Examples of how solvents (particularly those in the electronics
industry) are being reused and recycled.