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LFG Evaluation Memo December 4, 2013 Page 2 of 9 , GAS TESTING INSTRUMENTATION AND METHODS Testing for methane gas, oxygen gas, carbon dioxide gas, carbon monoxide, hydrogen sulfide and ' pressure was performed using a Landtec GEM-5000 Gas Analyzer calibrated to the various gases used(see attached instrument calibration logs). This instrument measures combustible gas ' concentrations in air directly on either of two scales,the first as percent by volume of the lower explosive limit(LEL) of methane gas in air(0 to 5 percent); the other as percent by volume (0 to 100 percent) in the gas sampled. The detection limit for this instrument is approximately 0.10 percent by ' volume for CH4, CO2 and 02 and approximatelyl part per million for both CO and H2S. Gas monitoring probe testing procedures are as follows: ' • Connect sample tubing, open test valve; observe pressure and record data. • Turn on sample pump, purge a minimum of one probe volume, observe and record ' methane, oxygen, and carbon dioxide gas concentrations,when readings have stabilized. • Close test valve, disconnect sample instruments and secure sample location. ' Testing for Volatile Organic Compounds (VOC's) was performed using a Minirae 2000 Photo Ionization Detector(PID) calibrated to isobutylene. This instrument measures VOC concentrations in air in parts per million by volume (ppmv). The detection limit for this instrument is approximately 0.1 ppmv. ' Testing for LFG Flow was performed using a Dwyer handheld velocity meter. This instrument measures flow directly in standard cubic feet per minute(SCFM). The accuracy of this unit is ' approximately+/- 10 percent of the value observed. Instrument Calibration Forms are provided in Attachment A. , LFG MONITORING PROBE TESTING RESULTS On October 25, 2013, SCS performed monitoring of all accessible LFG Monitoring probes around ' the facility boundary. Probe Locations are shown in Attachment B, Figure 1. The purpose of this testing was to determine if LFG migration was occurring in these areas and to quantify the results ' (see Attachment C, Table 1 for all probe monitoring data). The results of our testing indicated that no methane gas was detected at any location tested. These results indicate that as of the date of this report,the subject site perimeter probes are in compliance with the requirements of Title 27 CCR Article 6. Typically in non LFG impacted soils, it is typical to see no, or minimal amounts (up to 0.2%)of CO2 and no VOC's in subsurface soils. During our ' testing, SCS observed no VOC's at any monitoring probe tested. However,the presence of low levels carbon dioxide (Up to 6.6 percent by volume) in the subsurface soils is indicative of the presence of residual volumes of LFG in site soils at the facility boundary. , During our monitoring SCS observed that several test ports were in need of replacement due to observed deterioration. SCS recommends that replacement be performed to maintain proper ,