ARCHIVED REPORTS XR0001596 - Laserfiche WebLink

Home Browse Search

i The third type of information used by the NRC to evaluate bioremediation is illustrated using field data collected during the pilot study Soil samples collected from P-1 and P-2 were analyzed for bacteria numbers and types All samples analyzed showed increased densities of inoculated bacteria, as compared with pre-inoculation conditions An increase in bacterial numbers indicates successful bioremediation Also measured at the site was a decrease in oxygen (a growth stimulating material) and an increase in carbon dioxide (a by- product of bioremediation) The depletion of oxygen and the production of carbon dioxide indicate that the microbes are active at the Site I Overall, the depletion of oxygen and production of carbon dioxide was greater in wells that were inoculated but not provided an air source (via low pressure blower) This can be illustrated by comparing both the field measurements and laboratory analysis of oxygen and carbon dioxide in VW-1 and VW-4 In conclusion, data collected during the 60 day"pilot study" strongly suggests that engineered bioremediation is occurring or has the potential to have occurred at the Site in response to inoculation We now recommend the full scale initiation of a bioremediation project at the Site The following section will expand on the FRP and addendum, and attempt to address remaining questions and concerns of the CVRWQCB 3.0 FULL SCALE INOCULATION 3.1 Hydrocarbon Impacted Sail GeoAudit proposes to proceed with the full site inoculation as described in the FRP and addendum However, because some wells were inoculated during the pilot study, various modifications will have to be made In the FRP, GeoAudit proposed to inject inoculum into MW-1, MW-3, MW-4 and MW-5 and VW-1 through VW-7 In an addendum to the FRP, dated October 5, 1993, GeoAudit specified that each well would receive two well volumes, a total of 432 gallons would be injected in the monitoring wells, a total of 648 gallons would be injected into the remediation (VW) wells For the full-scale inoculation, GeoAudit proposes to inject approximately 100 gallons of inoculum each into MW-1, MW-3, MW-4 and MW-5 The inoculum will be injected using packers, in a similar manner as the pilot study However, the packer will be placed only at the 30 foot depth Impacted soil in the vicinity of VW-3 and VW-7 is primarily at depths greater than 35 feet Therefore, approximately 100 gallons will be inoculated into VW-3 and VW-7 using no packer yep l Au&j s� 3 IJ31C bo hr/S91