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Itis-FORMATION SHEET WASTE DISCHARGE REQUIREMENTS ORDER NO. R5-2003-XXX SPX CORPORATION MARLEY COOLING TOWER COMPANY GROUNDWATER EXTRACTION AND TREATMENT SYSTEM SAN JOAQUIN COUNTY Site Description and Background The Marley Cooling Tower Company(>fCTC), a wholly owned subsidiary of SPX Corporation (hereafter Discharger) owns and operates a groundwater extraction and treatment system in the East Stockton Area of San Joaquin County. The Discharger previously operated a cooling tower fabrication plant at the site which included a wood preservation process using solutions containing copper, chromium and arsenic. Wood preserving was discontinued at this facility in January 1991, however past operational practices have resulted in contamination of soils and groundwater underlying the site. Soils have been contaminated with copper, chromium, and arsenic; groundwater has been contaminated with chromium and copper. On 28 November 1984 the Regional Board ratified a Settlement Agreement between the Department of Health Services (now Department of Toxic Substances Control (DTSC)), the Discharger, and the Regional Board. This Settlement Agreement required the Discharger to conduct a Remedial Investigation/Feasibihty Study(RDFS) to define the extent of contamination, to develop a Remedial Action Plan(RAP), and to implement all measures necessary to remediate existing site contamination. Following discussions with Regional Board staff,DTSC formally adopted the RAP on 29 August 1990. The RAP included the conceptual design of the groundwater remediation project. The recommended groundwater remedial action in the RAP includes the extraction, treatment, and discharge of contaminated groundwater. To minimize dewatering of the local aquifer and to aid in flushing of contaminants, approximately 5% of the treated water is reinjected into shallow soils in the area of a closed retort pit. The injected water is then recaptured by the groundwater extraction system. The discharge of treated groundwater to the Stockton Diverting Canal was previously regulated by Waste Discharge Requirements (WDR) Order No. 93-221,NPDES Permit No. CA0081787, which was adopted by the Regional Board on?1 October 1993. Under this Order, the Discharger was permitted to extract groundwater and discharge a maximum of 0.94 million gallons per day(mgd) of treated groundwater and storm water runoff to the Stockton Diverting Canal, a water of the United States and a tributary to the Calaveras River. Groundwater Treatment Processes The groundwater treatment system at the plant includes an electrochemical reduction and precipitation unit operating in parallel to an ion exchange treatment system. The ion exchange system consists of two anion exchange vessels and a cation exchange vessel. In the anion exchange vessels, hexavalent chromium in the water is adsorbed onto the ion exchange resins. In the cation exchange vessel, trivalent chromium and copper are adsorbed. The exchange process continues until the resin's exchange sites are filled and exchange capacity is exhausted. The adsorbed wood treating chemicals are stripped from the ion exchange resins and the resins are