ARCHIVED REPORTS_2013_7 - Laserfiche WebLink

Home Browse Search

TABLE 19 ANTICIPATED EFFECTIVENESS OF ALTERNATIVES CORRAL HOLLOW SANITARY LANDFILL ENGINEERING FEASIBILITY STUDY Alternative Description Score Remarks Construction of an"impermeable"landfill cover is a proven means for source control. Precipitation and stormwater runoff will be diverted around this waste Final Cover segment. Reduction of waste moisture content will reduce landfill gas and No. 1 Extension 8 leachate generation. This alternative does not mitigate existing VOC impacts to groundwater. VOCs in groundwater suggest that landfill gas is the source. The site is currently equipped with 41 landfill gas extraction wells,though none have been Enhanced Landfill 9 constructed in the uncovered waste segment. Six new landfill gas extraction wells N°'2 Gas Extraction area proposed,and the expansion of the gas extraction system would target the uncovered waste segment,reducing the potential source of VOCs in groundwater. Technology has proven effectiveness for VOC removal in permeable aquifers, much less so in low-permeability aquifers that underlie the CHSL. In addition,the relatively shallow groundwater environment near well S13-1 may lead to short- No.3 IAS/VES 7 circuiting of the vapor extraction system that can occur in shallow aquifers. Since this approach delivers compressed air to the aquifer which will result in aerobic conditions,conditions will be less favorable for biodegradation. VOC impacts at the point of compliance have been observed for more than 10 years,with little change over time. However,the recent EMP results suggest that Intrinsic VOC concentrations reduce to extremely low concentrations within 1000 feet of No.4 Remediation 3 the POC. Historical observations suggest some degree of natural attenuation occurs in the upper aquifer beneath the site. There are no receptors in the immediate site vicinity. Groundwater extraction is a proven technology,though it requires careful design based on site-specific hydrogeologic conditions. The aquifer beneath the CHSL has not been characterized with sufficient detail to design an effective No.5 Groundwater groundwater extraction system,and as a result,the design of an appropriate Extraction with Air 6 extraction system would require a relatively detailed hydrogeologic investigation. Stripping The ultimate effectiveness of an extraction and treatment system depends on the ability to contain groundwater in the extraction well field to prevent offsite migration of impacted groundwater. Until a proper hydrogeologic characterization study is completed,the number of wells needed to achieve hydraulic containment is not known with certainty. Groundwater extraction will No.6 Groundwater remove VOCs and inorganics,though the treatment alternatives are only effective Extraction with 6 at reducing VOC concentrations. Each treatment alternative is supported by GAC Treatment extensive case studies proving their respective effectiveness. Alternative 5 has an advantage of not requiring treatment media,while Alternative 6 uses treatment media that must be replaced and disposed of periodically.