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OP,0,41!N C THOMAS R. FLINN 5 DIRECTOR 4tIF0RN THOMAS M. GAU CHIEF DEPUTY DIRECTOR MANUEL SOLORIO DEPUTY DIRECTOR STEVEN WINKLER DEPUTY DIRECTOR ROGER JANES BUSINESS ADMINISTRATOR January 5, 2007 Mr. Todd Del Frate California Regional Water Quality Control Board Central Valley Region 11020 Sun Center Drive, #200 Rancho Cordova, California 95670 P. O. BOX 1810 - 1810 E. HAZELTON AVENUE STOCKTON, CALIFORNIA 95201 (209) 468-3000 FAX (209)468-2999 www.sjgov.org/pubworks y n �I Ij 1___, {f I1E"��,,!� HEALTH PER01; /cE. VICES SUBJECT: PROGRESS OF LANDFILL GAS EXTRACTION; NORTH COUNTY RECYCLING CENTER AND SANITARY LANDFILL Dear Mr. Del Frate:� ) �0 This letter is written in response to your letter of December 15, 2006, in which you expressed concern that the landfill gas (LFG) system had not decreased the methane content at the monitoring wells as presented in the first semester monitoring report for that site. As we discussed, the LFG system was under construction at the preparation of the first semester report, therefore not operational, and we should not expect a decrease in methane content until the system is operational. The system began operation, although falteringly, in early December. A control problem causes the system to shut down, such that we are operating perhaps 80 percent of the time. The contractor has been alerted to this problem, and we hope that it will be corrected shortly. In the meantime, we are operating the system as much as possible. We were reluctant to attempt adjusting the well field until this problem was corrected, but it appears that it is difficult to diagnose, so we will proceed with the field adjustments as best we can in January. We propose to monitor soil gas wells SG5 and SG6 monthly to verify the effectiveness of the LFG collection system. Of the six soil gas wells ringing the refuse footprint, methane was found in these two wells in the first semester 2006. We anticipate that the methane content in the wells will gradually decrease. Our target methane content is 5 percent, and because the groundwater monitoring results show no impact since 2002, we believe that any reduction in methane content will indicate further assurance that the groundwater will not be impacted in the future. I regret if some passage in our report gave the impression that the LFG system was operating in the first semester 2006. Please do not hesitate to call me at (209) 468-8504 if, in the future, our reports seem to imply that something else is amiss.