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27 December 1996 <br /> AGE-NC Project No 95-0143 <br />' Page 10 of 19 <br /> 5 3 3 INOCULATION WELLS <br /> The effective radius of influence of inoculation wells is typically 15 feet Existing monitoring wells <br /> can be used for inoculation of ground water and the smear zone A greater radius of influence is <br /> usually obtained for ground water inoculation, since ground water movement can assist the bacterial <br /> migration However, additional vadose zone inoculation points would also be needed Temporary <br />' inoculation points could also be utilized <br />' 5 3 4 MONITORING ACTIVITIES <br /> After inoculation, the inoculation wells and ground water monitoring wells should be monitored for <br /> several months by periodic field measurements of organic vapor, carbon dioxide, and o\ygen <br /> concentrations Quarterly or semi-annual monitoring activities should include the installation of soil <br /> borings to collect soil samples to monitor bacterial populations, nutrient availability and soil <br /> remediation progress If monitoring indicates areas of slow remediation,additional inoculations may <br /> be required <br /> 5 3 5 DURATION <br />' Duration(and cost) are dependent on the volume of soil and water to be remediated, the number of <br /> inoculation and monitoring wells, the average concentrations of contaminants and nutrients, and the <br /> temperature and permeability of the soil Theoretically, the radius of influence of the inoculation <br /> well should increase rapidly at first, then gradually decline as the affected volume increases and the <br /> bacteria encounter decreasing hydrocarbon concentrations toward the margins of the hydrocarbon <br />' plume Shorter-chain hydrocarbons are typically consumed first and longer-chain hydrocarbons later <br /> Remediation at sites with similar lithologies typically takes between 18 and 36 months <br />' 5 3 6 FEASIBILITY <br /> No feasibility studies for in-situ bioremediation have been performed at the site If bioremediation <br /> is chosen as the method of remediation, soil samples should be collected and analyzed for <br /> physicochemical properties The results will be used to evaluate the need for parameter adjustment, <br /> if necessary, to facilitate effective biodegradation Due to the high concentrations of hydrocarbons, <br /> additional nutrients may be required to replace those consumed during remediation <br />