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© MONTGOMERY WATSON i TY-1 <br /> September 9, 1993 <br /> SEP 1G1993 <br /> C ry OP MANTF.CA <br /> DTTRT T^ ^^� - - nFP'T <br /> City of Manteca <br /> 1001 West Center Street <br /> Manteca, CA <br /> Attention: James Podesta <br /> Subject: Industrial Waste Discharge Permit Application, Libby-Owens-Ford, Co. <br /> Montgomery Watson, Inc. has reviewed the Industrial Waste Discharge Permit appli- <br /> cation submitted by Libby-Owens-Ford Company for the temporary discharge of <br /> treated cooling water. Libby-Owens-Ford plans to rebuild the glass furnace at its <br /> Lathrop facility. The glass furnace cooling water is treated with sodium dichromate <br /> to prevent corrosion in the cooling system. The cooling system contains 550,000 <br /> gallons of cooling water, and the chromium concentration is about 350 mg/l. <br /> Information on treatment of the proposed discharge and recommended requirements <br /> and conditions for accepting the Libby-Owens-Ford discharge are presented below. <br /> Description of Proposed Discharge <br /> The rebuilding of the glass furnace is scheduled for the fall of 1993. With the re- <br /> building of the furnace, Libby-Owens-Ford will eliminate the use of chromate cor- <br /> rosion inhibitors in the cooling system. The existing 550,000 gallons of cooling water <br /> requires will require disposal. Libby-Owens-Ford proposes to treat the cooling water, <br /> and discharge it to the City of Lathrop collection system at the Destec facility. <br /> The proposed cooling water treatment consists of acidfication to a pH of 2 with sulfu- <br /> ric acid. After acidification, the hexavalent chromium is reduced to trivalent chromi- <br /> um by the addition of sodium metabisulfite. The pH of the cooling water is then <br /> increased into the range of 8.5 to 10 by the addition sodium hydroxide. Under the <br /> alkaline conditions, an insoluble chromium hydroxide precipitate is formed. The <br /> cooling water is then filtered through a plate and frame filter press to remove the <br /> chromium hydroxide precipitate. The cooling water will be processed on a batch <br /> basis during a daily eight hour shift and will produce approximately 20,000 gallons of <br /> treated cooling water per day. <br /> 355 Lennon Lane Te 1.510 933 2250 Serving the World's Environmental Needs <br /> 14'alnut Creek.Caldorma Fax 5109334227 <br /> 94598-2427 <br />