ARCHIVED REPORTS_XR0011954 - Laserfiche WebLink

Home Browse Search

Work Plan-Soil and Groundwater Remediation CSUS Multi-Campus Regional Center,Stockton,CA March 3,2003 Page 7 of 8 soil samples will be collected in clean brass or stainless steel sampling tubes. The rod-mounted sampling tool will be cleaned prior to collection of each sample. The cleaning procedures will consist of washing the sample spoon in a solution of laboratory-grade non-phosphate detergent and de-ionized water, and double rinsing with de-ionized water. The soil verification samples collected from the excavation will be analyzed for benzene, toluene, ethyl benzene, and total xylenes (BTEX) by EPA Method 8020, total petroleum hydrocarbons quantified as gasoline (TPH-G) by EPA Method 8015M, and for gasoline oxygenates by EPA Method 8260B. The analytical methods and analytical detection limits are presented in Table 1, below. �� X12_�� Table 1 Laboratory Analytical Methods--Soil Verification Samples CONSTITUENT METHOD DETECTION LIMIT BTEX 8020 0.005 mg/kg(B,T,E);0.010 mg/kg(X) TPH-G 8015M 1.0 mg/kg Gasoline Oxygenates 82C0B 0,005—0.050 mglkg I Init C'onvemion- ug/kg:parts per billion(ppb);mg/kg:parts per million(ppm) 4.5 IN-SITU GROUNDWATER REMEDIATION 4.5.1 Ozone/Air Sparging Ozone sparging is an oxidation remediation process for in-situ remediation of chlorinated solvents and hydrocarbons and targets both soil and groundwater fractions. Micro-bubblcs of encapsulated ozone are introduced directly to groundwater through a network of injection wells. Velocity changes induced by intermittent operation of the injection wells create a circulation cell which exposes groundwater to micro-bubble treatment multiple times before it exits the circulation zone. Condor is currently evaluating the feasibility of a three to ten, ozone sparge points at the site. Injection points would be drilled to 75 feet bgs. The injection point wells will be constructed according to local regulatory mandates. An estimated radius of influence for each sparging unit is up to 25 feet. The number of injection points for ozone sparging is dependent upon lithology; therefore, pilot testing of the ozone sparging technique may be necessary to determine the required number of injection points for maximum efficiency. Additional injection points might be necessary to expand the field or two sparge points may be installed at different depths in the same borehole. The location of the proposed minimum injection points are shown in Figure 10, Appendix A. Actual well placement will be dependent upon radius of influence testing, traffic patterns, and overhead and surface conditions. Progress of the ozone sparging system will be monitored by collecting groundwater samples from monitoring wells MW-1, MW-2 and MW-3 during quarterly groundwater monitoring events. The three monitoring wells are located beyond the zone of influence of the proposed sparge points. Monitor well MW-3 is the only monitoring well located down gradient of the former UST location. J. 1 , W CONDOR