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LFG Evaluation Memo December 4, 2013 Page 3 of 9 monitoring capabilities, accurate results and limit the amount of atmospheric intrusion into the collection system. These results confirm that no methane gas is outside the property boundary of the Corral Hollow Landfill. However, SCS did observe that low level VOC's are present. Finally, SCS observed no evidence of bio-fouling or non-operational probes during our testing event. LFG EXTRACTION ELL MONITORING AND INSPECTION On October 15 and 16, 2013, SCS performed monitoring and inspection of the extraction well network. The purpose of these inspections was to determine the current configuration and operation with the intent to identify any possible problems or potential upgrades that could be performed to help improve/maximize LFG collection. At each location, SCS performed a visual inspection to verify current condition of components,vertical well liquid level and total depth sounding, video monitoring of the well casing at accessible locations and monitoring for overall gas quality, temperature, pressure and VOC's. This data is shown in Tables 2 and 3 and locations are on Figure 1. In addition, SCS took digital pictures at several locations during the inspection as a record of current conditions (pictures are provided in Attachment D). SCS compared the construction as-built depths at each perimeter well to the data obtained during our testing. Evaluation of the field monitoring results, video monitoring and our research indicated that no major watered in or perforation zone restrictions were observed at most extraction wells. Based on review of well sounding data collected, SCS believes that the total depth and low liquid levels observed indicate there are no well casings or perforation zone blockages inhibiting potential LFG extraction from the extraction wells tested due to liquids. Methane gas concentrations at the LFG Extraction Wells were generally low due to the age of the refuse, current state of vacuum distribution and the current operation of the LFG Flare Station (BFS). During extraction well inspections,we observed that the control valves were generally set to the open position(see Attachment C, Table 3). The adjustments and flow rates at the BFS may be contributing factors in the low levels of methane at the flare inlet. SCS recommends that an attempt should be made to re-adjust the wells to improve methane content and to decrease observed oxygen levels at the wells. SCS understands that in some cases operational constraints (i.e. vadose wells for VOC removal)may be contributing to the low methane content at the BFS,however, we recommend more frequent adjustment and tuning of the existing wells to maximize the LFG extraction rates and BTU content. VOC monitoring showed concentrations of up to 33.4 ppmv which indicates that the extraction wells are contributing to the removal of VOC's from the waste mass. Additional extraction from the locations containing the highest VOC concentrations may help reduce the observed VOC's outside the waste mass. During our monitoring activities,temperatures at the vertical LFG extraction well locations were monitored and observed to range from 55 to 90 degrees Fahrenheit(see attached data Table 2). The observed temperatures are considered to be in the normal range for anaerobic decomposition. In addition, SCS also performed testing for carbon monoxide (CO) at each individual LFG extraction well to verify that no evidence of subsurface oxidation was occurring in the waste fill.