SITE HISTORY - Laserfiche WebLink

Home Browse Search

r 1117 Lone PalmAve,Suite 201 Modesto,CA 95351 (Yt7J%TCPhone:209-579-2221 b" Fax: 209-579-2225 �. intensive, often requiring a hundred square feet or more of enclosed and level compound for equipment. In order to determine the effectiveness of SVE, a vapor extraction pilot test would need to be conducted. Data collected during the pilot test would be utilized to evaluate the necessity of soil remediation, as well as provide information to properly design a full-scale SVE remediation system. The installation of at least three SVE wells would need to be installed to conduct the pilot test. These wells would be screened in the vadose zone from approximately 20 to 40 feet bgs. Subsequently, a pilot test would be conducted using a mobile vapor extraction system. �.r The advantages of soil vapor extraction include: • Short treatment times; usually 6 months to 2 years under optimal conditions. • Readily available equipment. • Implementation with minimal disturbance to aboveground activities. • Proven performance over a wide range of conditions. • Cost competitive. 3.2 Groundwater Remediation Alternatives 3.2.1 Groundwater Extraction with Biological Treatment and Bio Enhanced Infiltration The groundwater extraction alternative involves recovering contaminated groundwater from the water saturated zone using groundwater extraction wells, surface filtration using a combination of aerobic and anaerobic biological processes, and re-injection of the treated water in the subsurface. Depending on the geology and soil type, pump and treat can be a viable method to quickly reduce high concentrations of contaminants and also capture or pursue contaminants which have migrated off-site. Although it is difficult to reach closure criteria concentrations due to the equilibrium of absorption/desorption processes in the saturated zone with regular pump- and-treat, the addition of biological enhancement can be effective in the destruction of the contaminants of concern. The impacted groundwater is mixed with predetermined micro- organisms designed to enhance natural biological processes. To determine the effectiveness of groundwater extraction and re-injection, an aquifer pump test and slug test would need to be conducted at the site. Data collected during the aquifer pump test would be utilized to evaluate the feasibility of this technology to remediate groundwater, as well as provide information to properly design a full-scale groundwater extraction and treatment system. In order to conduct the pump test at least three groundwater extraction wells would need to be installed. The extraction wells would be screened at approximately 40 to 55 feet bgs. Re- injection could be accomplished using existing on-site monitoring wells. Heterotrophic plate counts from the groundwater would be required to evaluate the indigenous bacteria. The plate count provides an estimate of the bacterial load in the groundwater. s:\environmental\22493\reports\feasibility.doc 9 V