printech, November, 2003
Re: Ask PNEAC: Adjusting pH of Film Spent Film Developer


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From: Gary Jones (gjonesprinting@aol.com )
Date: Wed, 19 Nov 2003 10:21:51


The response to your question is yes, the pH of the film processing solutions can be adjusted prior to discharge. The other important question is what pH level do you need to achieve prior to discharge. In most instances, sewer authorities have very generous pH ranges that they can accept, typically pH from 6-9, which is a wide range. Do you know what pH discharge limit you have to meet? This is found in the sewer code and if you have not already done so, you should obtain a copy of it.

If you are discharging to a septic system, then this practice should be stopped as septic systems are not designed to handle industrial discharges only sanitary wastes.

Have you tested the effluent from the processor to see what the current pH is of your effluent? If you do not have a fixer recycling system, the two solutions will usually neutralize themselves to the point of acceptability from a sewer code perspective. If you have a fixer recycling unit, then you may have to neutralize the developer prior to discharge.

If you are discharging to a sewer, it is also important to know and understand where the discharge limits are applied. Again, this is a function of the sewer code, but in most instances, it is where your sewer line meets their sewer line. What this means is that the pH and other pollutants in the effluent will be tested at the sewer connect and the levels that get measured at this point are usually lower than those measured at the processor discharge. Gary Jones Graphic Arts Technical Foundation



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