Laserfiche WebLink
r <br /> r20 January 2005 <br /> AGE-NC Project No 97-0343 <br /> IPage 19 of 21 <br /> r characteristic of passive biodegradation Natural attenuation is normally used where low <br /> concentrations of hydrocarbons are present or after completion of another method of remediation <br /> I10 3 2 Duration <br /> r The duration for natural attenuation can be many years Costs for natural attenuation are generally <br /> lower than most active remediation options However,costs can be highly variable depending on the <br /> duration and type of monitoring required Fate and transport modeling may be used to demonstrate <br /> rthe potential for hydrocarbons to impact nearby ground water receptors <br /> r10 3 3 Feasibility <br /> Quarterly ground water monitoring may be used to monitor and document development of a stable <br /> and declining ground water plume and declining hydrocarbon concentrations Data collected to date <br /> is not sufficient to adequately assess the feasibility of utilizing natural attenuation for site <br /> remediation <br /> I10 3 4 Estimated Costs <br /> It Is likely that some additional laboratory analysts of ground water samples would be required to <br /> r monitor and verify natural attenuation A long-term monitoring program of perhaps 10 years, may <br /> be necessary Quarterly monitoring and sampling and report preparation could cost between$6,000 <br /> to $20,000 annually Therefore, the total cost for natural attenuation could range from $60,000 to <br /> r $200,000 <br /> r11.4. RECOMMENDATIONS <br /> AGE has evaluated three methods to remediate hydrocarbon-impacted soil and ground water on the <br /> r subject site In view of site specific conditions, the principles of the remedial methods, the <br /> advantages and disadvantages of each remedial method and AGE's experience with each method, <br /> AGE recommends that impacted soil and ground water at the site be addressed as described below <br /> r <br /> 11 1 REMEDIATION OF HYDROCARBON-IMPACTED SOIL <br />' <br /> Significant petroleum-hydro impact to soil In the vadose zone appears to be limited to the area <br /> • � p Y p pP <br /> rAdvanced GeoEnvironmental,Inc <br /> r <br />