ARCHIVED REPORTS_2007_5 - Laserfiche WebLink

Home Browse Search

4.0 ANNUAL SUMMARY 4.1 GENERAL During the 2007 monitoring year, groundwater elevations and groundwater and surface water sampling was performed at the Forward Landfill on a quarterly basis. The groundwater and surface water samples are analyzed for the monitoring parameters summarized in Table 2-1, and a summary of the 2007 annual monitoring data is provided in Appendix C. Time-series plots and piper diagrams depicting groundwater and surface water constituent concentrations are presented in Appendix D, and an electronic copy of the historical data is included in Appendix C. In addition, well hydrographs illustrating historical groundwater elevations, well screen elevations, and pump intake elevations are also included in Appendix D. According to the Forward Landfill Operations Manager, Forward Landfill received a total of 1,324,988 tons of solid waste during the 2007 monitoring year. Figure 1-3 shows the approximate location of waste placement during 2007 monitoring year. The following types of waste were received: Non-hazardous solid waste— 1,293,440 tons Asbestos—6,835 tons Sewage and wastewater treatment sludge—24,713 tons 4.2 LANDFILL GAS MONITORING During the first quarter 2007 landfill gas monitoring activities, the CEHD regularly measured methane in perimeter soil-pore gas probes GP-11 and GP-12 at concentrations exceeding perimeter action levels of 5 percent. However, since the April 2007 inspection methane concentrations in all perimeter soil-pore gas probes have remained below 5 percent, suggesting that the landfill gas extraction system is effectively reducing methane concentrations along the perimeter of the site. Furthermore, in accordance with CCR 27, Section 20937(a) (1), methane monitors are installed in all buildings at the site to protect public health and safety and the environment. During the 2007 monitoring year, no methane was detected in any of the facilities buildings. 4.3 COMPLIANCE RECORD During the 2007 monitoring year, CLs were consistently exceeded in Forward Unit wells MW-IA, MW-2A, MW-3, MW-10, MW-13, MW-14, MW-15, MW 16, MW-17, MW-18, MW-19, and MW-21 and sporadically in well MW-23R. The inorganic CL exceedances have been measured and verified in retest samples collected from the monitoring wells at the Forward Unit, followed by NRD. In each case the NRD has concluded that the CL exceedances are likely the result of naturally occurring conditions and therefore not indicative of a release from the Forward Landfill. 1):12007 0043\ForwardAosfln 4Q07.doc 14 Geologic Associates