CORRESPONDENCE_2009-2010 - Laserfiche WebLink

Home Browse Search

ID THOMAS R. FLINN DIRECTOR THOMAS M. GAU CHIEF DEPUTY DIRECTOR MICHAEL SELLING DEPUTY DIRECTOR STEVEN WINKLER DEPUTY DIRECTOR ROGER JANES BUSINESS ADMINISTRATOR qlp.rlmn�W Mr. Todd Del Frate T*T 19 T 94 9 -e A-0 1 -11 11 1 milk 11 P. O. BOX 1810 - 1810 E. HAZELTON AVENUE STOCKTON, CALIFORNIA 95201 (209) 468-3000 FAX (209) 468-2999 www.sjgov.org/pubworks SUBJECT: FOURTH QUARTER 2009 GROUNDWATER MONITORING REPORT, CORRALOLLOW SANITARY LANDFILL Dear Mr. Del Frate: /I 0 In general, groundwater conditions remain consistent with those of the previous year. No VOCs were reported at shallow aquifer wells SB -1 or MW -4, or at any deep aquifer well. Seven VOCs were reported in impacted well MW -5, two of which were in trace concentrations, none above 10 ppb. We expected to see more improvement in water quality at wells MW -4 resulting from the increased collection of LFG from that area. The new LFG wells are withdrawing significant quantities of gas (including air) from the refuse in which they were installed, such that the methane content from new wells EW -40 through -43 is no greater than 0.2%. We will increase the vacuum applied to these wells, and expect gradual improvements. The results from well MW -8 were unusual. Although only four VOCs were reported at this well, Carbon Tetrachloride was reported at 80 ppb, which is an unusually high concentration for a compound that has not been previously reported in either that well or upgradient MW -5. These fata support the speculation that the high reported concentration of Carbon Tetrachloride was due to a laboratory error. If this datum is disregarded, then the VOC concentrations at MW -8 appear to be improving. We look forward to this theory being confirmed by the next quarter's data. However, in response to this new data and out of concern that Well MW -5 is not noticeably improving, we have directed that LFG collection be increased from LFG wells EW -1 1 and -15. The methane content of these wells are approximately 25 percent, and we would not normally increase collection from wells with such low methane content. We feel that such action is [,.varranted under these circumstances.