FIELD DOCUMENTS_1987 - Laserfiche WebLink

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WASTE DISCHARGE REQUIREMENTS -2 THE MARLEY COOLING TOWER COMPANY STOCKTON, SAN JOAQUIN COUNTY 8. Past use of copper, chromium, and arsenic wood treatment compounds has resulted in contamination of soils and ground water underlying the site. First ground water is approximately 40 feet below ground surface. The contamination sources are the Retort Pit and Stormwater Retention Pond (no longer in use) , identified in Attachment B. Soils have been contaminated with copper, chromium, and arsenic; ground water has been contaminated with chromium and copper only. A ground water contamination plume exceeding the Drinking Water Standard of 50 u9/1 for chromium, extends off-site threatening local domestic supplies. 9. The Board, on 28 November 1984, ratified a Settlement Agreement between the Department of Health Services, the Discharger, and the Board, which requires the Discharger to define the extent of contamination, develop a mitigation plan, and implement all measures necessary to remediate existing site contamination. The Discharger is performing these tasks in accordance with the Agreement. 10. As part of the mitigation measures, the Discharger proposes to pump and discharge ground water from beneath the site to the on-site treatment plant before discharge. 11. The Report of Waste Discharge describes the combined stormwater and ground water characteristics prior to treatment as follows: Average Flow: 0.37 million gallons per day (mgd) Design Flow : 0.370 million gallons per day (mgd) Average Temperature: storm water - ambient ground water - 68°F Constituent Stormwater (mg/1 ) Ground Water (mg/1 ) Total Chromium 5.0 20.0 Chromium VI 4.5 20.0 Copper 4.34 <0.05 Arsenic 0.04 <0.01 12. Both stormwater and ground water will be treated at an on-site treatment plant constructed and operated by the Discharger. Treatment will consist of flow equalization, settling, filtration, pH adjustment, and ion exchange. 13. From 1 October to 1 April , all flow in the Calaveras River is diverted at Bellotta to Upper Mormon Slough, tributary to the Stockton Diverting Canal , tributary to the Calaveras River (see Attachment C) . No flows are maintained in the Calaveras River channel between the fork with Upper Mormon Slough and the confluence with the Stockton Diverting Canal .