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SCS monitored structures by testing randomly selected locations where methane gas would most
<br />likely accumulate (e.g., electric outlets, junction boxes, conduits, drains, cabinets, and closets).
<br />Other required monitoring documentation (e.g., sampling personnel, date, time, and meteorological
<br />conditions) are shown on the attached testing data tables.
<br />GAS MONITORING PROBE TESTING
<br />In accordance with the approved testing schedule, all perimeter compliance GP probes are to be
<br />tested at a minimum on a quarterly basis. On April 29, April 30, June 20, and June 24, 2025, all
<br />accessible perimeter Gas Monitoring Probes defined as GP -01 through GP -28R were tested for the
<br />presence of LFG.
<br />Test results (Table 1) indicated that all GP probes exhibited methane gas concentrations below the
<br />LEL (5 percent by volume), or no methane gas was detected. These results indicated that as of the
<br />date of this report, the subject site perimeter probes are in compliance with the requirements of Title
<br />27 CCR Article 6.
<br />SCS is scheduled to perform the third quarterly monitoring of 2025 (July through September) of the
<br />GP probes by the end of September 2025, or more frequently as directed by Republic.
<br />NEW POINT OF COMPLIANCE MONITORING PROBE TESTING, SITE -WIDE
<br />WDR LOCATIONS
<br />In accordance with the approved testing schedule, all perimeter compliance GP probes are to be
<br />tested, at a minimum, on a quarterly basis. During this reporting period, all accessible perimeter Gas
<br />Monitoring Probes defined as GP -1A through GP -6A and GP -10 through GP -15 were tested for the
<br />presence of LFG.
<br />The results of this monitoring indicated that LFG Monitoring Probe Nos. GP-1AD, GP-1AM, GP-1AS,
<br />GP-2AD, GP-2AM, GP-2AS, GP-6AM, GP-6AS, GP -10D, GP -10M, GP -10S, GP41S exhibited VOC
<br />concentrations in excess of the 10 PPB standard. The highest VOC reading was observed at LFG
<br />Monitoring Probe No. GP -10M (up to 6.2 ppm). No methane gas was detected at any location
<br />monitored in excess of 1 percent by volume, except for LFG Monitoring Probe Nos. GP -10D (42.0
<br />percent by volume), GP -10M (41.8 percent by volume), and GP-1OS (35.8 percent by volume)
<br />(please see Table 1). Note that these probes are intended for evaluation purposes only and are not
<br />Title 27 compliance locations. As required, on October 7, 2024, annual samples were obtained and
<br />analyzed using EPA method TO -15. These results were submitted directly to Republic. The next
<br />annual sampling event will be performed by the end of November 2025 or as requested by the
<br />client.
<br />SCS is scheduled to perform the third quarterly monitoring of 2025 (July through September) of the
<br />GP probes by the end of September 2025, or more frequently as directed by Republic.
<br />ON-SITE INTERIOR STRUCTURE TESTING
<br />In accordance with the approved testing schedule, the interiors of on-site structures are to be tested,
<br />at a minimum, on a quarterly basis. On June 20 and 24, 2025, on-site structures (i.e., landfill office,
<br />scale house, breakroom, storage container, and maintenance room) were tested for the presence of
<br />methane gas. In each structure, randomly selected locations (i.e., electrical outlets and junction
<br />Forward/Austin Landfill -Second Quarter 2025 www.scsenaiineers com
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