FIELD DOCUMENTS AND WORK PLANS 1992-1999

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MEMORANDUM * CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD - CENTRAL VALLEY REGION 3443 Routier Road, Suite A Phone: (916) 361-5600 Sacramento, CA 95827-3098 �1 / ATSS Phone: 8-495-5600 TO: Antonia K. J. Vorsterl',� J FROM: Camilla Williams Senior WRC Engineer 1 1 Engineering Geologist DATE: 7 January 1992 SIGNATURE: ii7 �iui/� ../� SUBJECT: REVIEW OF EVALUATION OF TREATED WATER DISPOSAL OPTIONS, MARLEY COOLING TOWER COMPANY. SAN JOAQUIN COUNTY I have reviewed the Evaluation of Treated Water Disposal Options report for the Marley Cooling Tower Company (Marley) site. The Report was submitted on 5 August 1991 and was prepared by Black and Veatch. I have withheld my review of this Evaluation Report pending my review of the Ground Water Injection Feasibility Study (FS) Report, prepared by Hargis and Associates and submitted on 9 September 1991, because the Disposal Options Evaluation Report heavily references the Injection FS Report. My review comments on the FS Report are in a separate memorandum. The Evaluation of Treated Water Disposal Options was prepared in compliance with the Remedial Action Plan and the revised National Pollutant Discharge Elimination System (NPDES) permit, Waste Discharge Requirements (WDRs) Order No. 91-035. The Evaluation Report considers different sources and the costs of water in the area, compares the continued discharge to the Stockton Diverting Canal with injection into the aquifer for disposal , presents other disposal options that were considered but not evaluated, and presents an evaluation of the disposal option based on effectiveness, implementability and economic merits. The Evaluation Report does not provide a conclusion based on the evaluation of the disposal options. Table 4-1 (page 4-2) of the Evaluation Report summarizes the evaluation of the discharge to surface water, injection into the Intermediate Zone and injection into the Deep Zone. In general , the Table indicates that injection into the aquifer is feasible. The cost analysis shows that surface water discharge is the least costly (with an estimated total present worth of about $9,900,000) and injection into the Intermediate Zone incurring the greatest costs (with the estimated total present worth costs at about $11,500,000) ; the difference being about $1,600,000. This cost difference indicates that injection appears to be too costly to implement. One of the major problems with the Evaluation Report is that conclusions or recommendations were not presented. Marley should have provided a conclusion of whether or not treated water disposal to the Stockton Diverting Canal should remain the preferred disposal option. Marley should continue to investigate and report on other potential reuse options on a periodic basis, such as the renewal of the NPDES permit, because the value of this resource may change during remediation. The other major problem with the Evaluation Report is that reuse of the treated ground water in the subsurface soil flushing system was not addressed. It is my understanding that Marley intends to reuse the treated water in the final flushing system which is currently under construction. Because the reuse of the treated water would impact the aquifer, a Report of Waste Discharge (RWD) is required and new WDRs would need to be issued.