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A? <br /> ,wlt'l <br /> E <br /> PES Environmental, Inc. <br /> l Mr. Jeff Werner <br /> February 12, 1991 <br /> Page S <br /> judgement. The time required to obtain a NPDES permit can b� up to six <br /> engin <br /> kid judg ds in <br /> monthss,. obviously, the time required to startup ant[ interim treatment system depen <br /> part on the time required to obtain a NPDES pe <br /> Air stripping without air emission controls would not be appropriate for groundwater that <br /> t contains high concentrations of benzene. The San Joaquin Air Pollution Control District <br /> regulates ak emissions from air stripping towers and requires the use of air emission controls <br /> i whoa ben=c errtsstans result in additional cancer risks to exranular activated carbon or risk <br /> level. The use of air emission controls such as vapor phase g <br /> thermal incincraticm nullifies the cost-effectiveness of this treatment option. <br /> G For this particular site, biotreatment, chemical oxidation, or carbon adsorption are the most <br /> !" technically feasible technologies for groundwater remediation- Table 1 presents some <br /> and disadvantages of each of these treatment technologies. A detailed evaluation <br /> advantages <br /> l� of site-specific ftc data however, will provide information required to design the most cost- <br /> of performing a <br /> effective treatment system- PFS will employ the following methodology <br /> 1 <br /> detailed cost analysis of the treatment system: <br /> I v` iftc data from the extraction well, such as: (1) the range of flocrrdtes <br /> Collect site-spec <br /> • <br /> that can be achieved from pumping; (2) the variability of petroleum hydrocarbon <br /> a concentrations during groundwater pumping; (3) the inorganic water chemistry (such <br /> .F..r as hardness and:nerals content); and (4) the biological composition of the <br /> groundwater. This data will be obtained from bath existing data and new information <br /> obtained from Task 3 activities. <br /> • Based on site-specific data, PES will: (1) size biotreatment, chemicalxi at an and <br /> k <br /> carbon systems from corrrnercially available off-the-shelf units: (2) pe <br /> rl nts of the <br /> preliminary assessment regarding pre- or post-treatment require are a detailed <br /> aV <br /> groundwater for each of the treatment technologies; and (3) p P <br /> estimate of operation and maintenance costs for each treatment cost. <br /> • The cost analyses of each treatment technology will be compared to each other so that <br /> } the most cost-effective treatment system <br /> t: performance of treatment systems <br /> this <br /> procedure, PFS can assess the comparative cost <br /> l over time rather than base system selection sojvly on initial costs. As an exaMpie, <br /> 9 carbo <br /> carbon systems are typically less expensive in terms of capital costs- <br /> replacement <br /> replacement costs can make the expense of operating such a system p <br /> Computer modeling of a W gallon per minute system, pumping water with typical <br /> concentrations exhibited in nearby Well MW-8. indicates a carbon usage rate for this <br /> site of about 15 pounds per day. This correlates to an annual carbon.rthe extractention cost <br /> of approximately $15,000 per vear. if, however, the pumping rate of the extraction <br /> h system is 20 gallons per,minute, the costs annual carbon replacement costs will be <br /> -�� -� rim <br />