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Treated Water Disposal Evaluation -2- 7 January 1992 <br /> Marley Cooling Tower Company <br /> My comments on the Evaluation Report are discussed below. <br /> Page 1-3. The Report discusses the effect of the remediation on water resources. <br /> Marley estimates that approximately 700,000 gallons per day will be <br /> extracted and treated. However, the Report fails to estimate how long the <br /> remedial action will be needed. An estimate of the duration of the <br /> remedial action is crucial to the cost analysis of the different proposed <br /> disposal actions. <br /> Page 2-2. The Report states that direct reuse of Marley's treated water as a public <br /> water supply has not been accepted by state agencies. This disposal option <br /> was not considered for evaluation. The Board considers the reuse/recycle <br /> option to be the most favorable as long as the requirements of all public <br /> water agencies are met. Therefore, reuse as a public water supply would be <br /> supported by the Board. In addition, continued drought conditions may <br /> change attitudes regarding treated water as the value of this resource is <br /> realized. Marley needs to continue to investigate and report on potential <br /> reuse disposal options. <br /> Page 3-4. The Evaluation Report states that to minimize the potential for scaling <br /> associated with injection into the deep zone, the wells should be screened <br /> below 250 feet below ground surface (bgs) . The Injection FS did not <br /> recommend this design for the extraction well system, but rather <br /> recommended screening the entire deep zone (200 to 400 feet bgs) with <br /> additional treatment of the effluent prior to disposal . In addition, the <br /> interval between about 200 and 250 bgs may be a highly transmissive zone <br /> that would be needed to maintain an injection rate of 500 gallons per <br /> minute (gpm) . <br /> Page 3-4. The Report lists other disposal options considered in previous studies. <br /> These options include industrial reuse, agricultural reuse, infiltration <br /> basins or recharge trenches and reuse as a water supply. An additional <br /> reuse disposal option which apparently has not been considered before, is <br /> that of reuse of the treated ground water in the subsurface soil flushing <br /> system. It is my understanding that Marley is not using the treated water <br /> in the interim subsurface soil flushing system but intends to use it in the <br /> final system. We strongly support this reuse. Therefore, it is unclear <br /> why reuse in the existing or final (currently under construction) was not <br /> evaluated for this report. The reuse of the treated effluent in the <br /> subsurface soil flushing system may be a disposal alternative that can be <br /> used in conjunction with other selected disposal methods. <br /> In addition, reuse of the treated water in the final subsurface flushing <br /> system, will require new WDRs because of the direct impacts of this <br /> discharge on the aquifer. Because the final subsurface soil flushing <br /> system is currently under construction, these WDRs could be issued <br /> simultaneously as the modification of the NPDES permit, should Marley <br /> pursue this disposal option. <br /> Page 4-1 . Table 4-1 present the summary of the different disposal alternatives <br /> considered for the evaluation. Listed below are several comments on the <br /> evaluation. <br />