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Attachment C Page 8 of G <br /> SIGMA CIRCUITS Inc . , CITATION DIVISION <br /> FIELD SITE <br /> TREATMENT UNIT OPERATION <br /> UNIT 2 (Continued ) <br /> Process: <br /> A) Spent stripper is pumped from the process to the BTT <br /> and may be blended with spent equipment cleaner . Other <br /> concentrated metal-bearing wastes are also pumped to <br /> this BTT for treatment . <br /> B ) The stripper (or stripper/equipment cleaner blend ) is <br /> treated by lowering the pH to about 4 by addition of <br /> sulfuric acid . This process precipitates the resist <br /> and the metals . The sludge is then allowed to settle <br /> in this tank . <br /> C ) After an appropriate settling time , the sludge is <br /> pumped through the filter press and the filtrate from <br /> the press is pumped through the CWTS and processed as <br /> described in Unit 1 . <br /> D) After each sludge run , as with the CWTS sludge, the <br /> filter press is opened up and the sludge scraped off <br /> the plates into the bin . The contents of this <br /> collection bin are then transferred directly to <br /> reusable plastic bins for shipment offsite. <br /> E ) Other metal-bearing wastes are also treated in the BTT <br /> by various waste treatment processes. The sludge and <br /> filtrate from the press are monitored , sampled , <br /> analyzed , and handled in the same manner as with spent <br /> stripper . <br />