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INFORMATION SHEET <br /> WASTE DISCHARGE REQUIREMENTS ORDER NO.R5-2002-XXX <br /> MARLEY COOLING TOWER COMPANY <br /> GROUNDWATER EXTRACTION AND TREATMENT SYSTEM <br /> SAN JOAQUIN COUNTY <br /> Site Description and Background <br /> The Marley Cooling Tower Company(MCTC), a wholly owned subsidiary of SPX Corporation <br /> (hereafter Discharger) owns and operates a cooling tower fabrication plant in the East Stockton <br /> Area in San Joaquin County. As part of the fabrication operations, the Discharger operated a wood <br /> preservation process utilizing solutions containing copper, chromium and arsenic. Wood <br /> preserving was discontinued at this facility in January 1991,however past operational practices <br /> have resulted in contamination of soils and groundwater underlying the site. Soils have been <br /> contaminated with copper, chromium, and arsenic; groundwater has been contaminated with <br /> chromium and copper. <br /> On 28 November 1984 the Regional Board ratified a Settlement Agreement between the <br /> Department of Health Services (now Department of Toxic Substances Control (DTSC)), the <br /> Discharger, and the Regional Board. This Settlement Agreement required the Discharger to <br /> conduct a Remedial Investigation/Feasibility Study(RDFS) to define the extent of contamination, <br /> to develop a Remedial Action Plan(RAP), and to implement all measures necessary to remediate <br /> existing site contamination. Following discussions with Regional Board staff,DTSC formally <br /> adopted the RAP on 29 August 1990. The RAP included the conceptual design of the groundwater <br /> remediation project. The recommended groundwater remedial action in the RAP includes the <br /> extraction, treatment, and discharge of contaminated groundwater. <br /> To minimize dewatering of the local aquifer and to aid in flushing of contaminants, approximately <br /> 5% of the treated water is reinjected into shallow soils in the area of a closed retort pit. The <br /> injected water is then recaptured by the groundwater extraction system. <br /> The discharge of treated groundwater to the Stockton Diverting Canal was previously regulated by <br /> Waste Discharge Requirements (WDR) Order No. 93-221,NPDES Permit No. CA0081787,which <br /> was adopted by the Regional Board on 22 October 1993. Under this Order, the Discharger was <br /> permitted to extract groundwater and discharge a maximum of 0.94 million gallons per day(mgd) <br /> of treated groundwater and storm water runoff to the Stockton Diverting Canal, a water of the <br /> United States and a tributary to the Calaveras River. <br /> Groundwater Treatment Processes <br /> The groundwater treatment system at the plant includes an electrochemical reduction and <br /> precipitation unit operating in parallel to an ion exchange treatment system. <br /> The ion exchange system consists of two anion exchange vessels and a cation exchange vessel. In <br /> the anion exchange vessels, hexavalent chromium in the water is adsorbed onto the ion exchange <br /> resins. In the cation exchange vessel, trivalent chromium and copper are adsorbed. The exchange <br /> process continues until the resin's exchange sites are filled and exchange capacity is exhausted. <br /> The adsorbed wood treating chemicals are stripped from the ion exchange resins and the resins are <br />