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- - ~ .r. ~ wvv 1 ~ ~ ub N. 06 <br />~, ~.rn A 6~.: II' 2QD <br />Wentlfiea~lon of the tielecbd Remedy <br />Institutional controls for the selected remedy are reflected in Appendix B. Those institutional <br />controls are intended to prevent the future use of groundwater exeoedigg romediation goals. <br />~:.. The Offpost Groundwater Intercept and Treatment System is an a7riy of extraction wells and <br />recharge trenrl7es is the northern and First Creek palsocha7mels. The system is configured to extract <br />r <br />sad treat LTFS groundwater that exceeds containment system remediation goals and to recharge the <br />.. treated groundwater. Figure 7.1 presents the placement of extraction wells and recharge wells in the <br />northern paleochannel end the placement of extraction wells sad recharge trenches in the First Geek <br />paleochannel. The location of the treatment facilit}• is also shown in Figure 7,1. The northern paleo- <br />,. <br />n channel collection system consisU of 12 extraction we1La spaced approximately 200 feet apart across <br />`;:. the paleochennel, perpendicular to the direction of groundwater flow. The recharge ryatem is the <br />r northern paleochanael consists of 24 recharge wells spaced 100 feet apart and placed parallel to and <br />approximately 300 feet dowggr-adiant of the collection system. I'he First Ctaalc paleoehsanel <br />collection system consists of 5 extraction wells spaced 200 to 500 feet apart along the axis of the <br />paleochannel. Recharge trenches era placed such that tour of the cix trenches ere pazallel to the flow <br />axis and located oa the margins of the paleocha7tnel. with the remaining two trenches located <br />I dow7lgradieat of the extraction well system and oriented perpendicular to the flow axi,. <br />The system is designed to eoch-act and treat an average flow of 300 gpm from the northern paleoehan- <br />eel, an average flow of 1110 gpm from the First Creek palaochaanel, sad a peak flow of 1.5 times the <br />average flow. Tha treatment facility basic process flow includes influent storage, pumping, bag <br />filtration for particulate removal, carbon adsorption, multimedia filtration, treated water storage, <br />treated water pumping, and final bag filtration. <br />~~ <br />A total of approximately 250 million gallons per yeaz would be treated by the Offpost Groundwater <br />~~ Intercept and Treatment System at the average flows. In addition, operation of the NBCS component <br />of this alternative will treat approximately 125 million gallons per year. Thus, a total of apprord- <br />.. 8d Haed(ny Larson pssodatas 'rises aotolo <br />0:]7721895 R02 <br />ar <br />