SITE INFORMATION AND CORRESPONDENCE FILE 1

Home Browse Search

low yield aquifers that often go dry with conventional pumping do not go dry when pumping involves EVR. This feature is also useful in.the recovery of LNAPLs from the groundwater surface. If groundwater and LNAPL are pumped from a well subjected to EVR, there is "a depression in the water table potential without depression of the actual water table, which causes water and LNAPL to flow toward the well." (Millan, 1992). Success in the recovery of both air and groundwater with vacuum demonstrates that a commercially available pre-packaged recovery/treatment system can eliminate the need for pumps, downhole water level switches, and timers. In addition, application or addition of EVR technology is relatively inexpensive. 6.0 Summary The EVR pilot study that is the subject of this paper represents the progression of previous work using non-enhanced vacuum recovery of groundwater and product (Hix 1992, Schaal, 1992). The results indicate that a two-fold increase in groundwater production is possible from low yield aquifers. Key advantages of this result include reduction in the number of wells required to achieve specific well field production, elimination of well pulsing strategies which require time-essential aquifer recharging, and a potential reduction in the length of time required to complete remediation. Cost savings may be realized in O&M and schedule. The application of EVR in a well encourages the flow of groundwater and LNAPL to that well by increasing the piezometric gradient for groundwater and LNAPL and overcoming j interstitial pore pressures. The movement of air through the subsurface induced when subjecting wells to vacuum enhances SVE removal of LNAPL vapors and adsorbed-phase VOCs and supplements oxygen for aerobic microbial remediation of organic compounds.. `Y JJL 1 ' 1 521 I C