From: Brigette Martin (BMARTIN@gulf-states.com)
Date: Thu Mar 16 2000 - 10:53:03 CST
Gary, some of these chemicals start off with a ph of 12 of higher and a very
large amount of water would need to be mixed to bring it down to acceptable
levels. Our problem is that these are usually piped directly to the sewer so we
can sample pH prior to disposal.
I need a way to verify that the pH is in acceptable ranges and meets POTW
standards. Mass flushing with water may not help achieve these levels.
We will continue to investigate....b
>>> <email@example.com> 03/16 8:26 AM >>>
The vast majority of printers discharge their prepress waste to a POTW
without needing to neutralize for pH. Most sewer authorities will accept a
wide range of pH in the effluent commonly in the 5-9 range. The effluents
from prepress will fit into this range as the film developer and fix will
neutralize each other. However, using a fixer recycling unit will change this
balance as the fix will not be available and the pH of your effluent will
rise. Also, some direct to plate systems can also have a high pH.
For those printers using a septic system, they are not allowed to discharge
any industrial effluents. These printers, as well as the ones where their
POTW will not accept their effluent, have to collect the wastewater and
solutions and have them sent off-site for disposal. This is expensive and
some printers use evaporators to reduce the volume of waste sent off-site.
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