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RE: Concrete Batch Plant Wastewater

Hello, John:

I've seen a few here in Orange County.  Discharge of wastewater to sewer
over time caused restriction in sewer pipe diameter.  Line cleaning was
difficult and time consuming to remove the material.  These places don't
discharge to the sewer in my county anymore.

Equipment and trucks are cleaned with water.  The layout is set up so that
this flows into a concrete pit.  The solids settle out. The water is reused
for cleaning.  When the reuse water becomes murky, the solids are removed
from the pit with a tractor.  These solids are recycled back into the cement
process.*  The displacement in the pit, afforded by the removal of solids
from the pit, allows fresh water to again be used in the cleaning process;
and, renews the quality of the reuse water in the pit until solids must
again be removed.

It doesn't rain as much here as in Palau.  The pit will need an appropriate
berm configuration and roof or rain cover to prevent discharges to surface

*Reuse of solids and even pit water may vary depending on the quality
specifications of each individual type concrete product produced; also, the
amount of work that may be necessary to blend these into the product to
achieve the desired specification for the final product.

It's been a very long time since I've inspected one of these places, so,
that is the best I can recollect on the subject.

Please forward my email address to the contractor on Palau.


						Source Control Inspector
-----Original Message-----
From: Katz.John@epamail.epa.gov [mailto:Katz.John@epamail.epa.gov]
Sent: Thursday, October 05, 2000 2:38 PM
To: p2tech@great-lakes.net; p2@ucsd.edu
Subject: Concrete Batch Plant Wastewtaer

P2'ers -

Have a semi-P2 request below from Palau (Pacific Islands). Anybody have
information on how these operations are regulated here in the States? Any P2
suggestions? Please forward them to me - I will compile the responses and
them on.


John Katz
US EPA Region 9


Hello -

I have inquiry regarding wastewater discharges from concrete batch
plants. These facilities are beginning to proliferate here in Palau and
can add to the water quality problems.   Our approach is to begin
including the following discharge conditions:
Either 1) Recycle concrete wash wastewater from water from trucks as
concrete mix water, 2) Dispose of ocncrete mixer washwater onsite,  or
3) Discharge must basically meet pH limits of 7.7 to 8.5 and TSS limits
of 50 mg/L.
Even testing for TSS is a problem in Palau because there are no labs.
  I was curious to know how concrete batch plants are being handled in
the region.
Any info or assistance is appreciated