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SECOND QUARTER 2007 GROUNDWATER TREATMENT FACILITY MONITORING REPORT FORWARD LANDFILL WDR ORDER NO.R5-2003-0080 with the meteorological station using the telephone line since October 2006. Geo-Logic is only able to download data by connecting a laptop computer to the station while onsite. Therefore,it is highly unlikely that the meteorological station is interfering with the GTF radio transmissions. As discussed in Section 3.0,the GTF was shut off on May 23,2007,because methylene chloride and PCE were detected at low concentrations in the effluent sample collected on May 1, 2007.The GTF was restarted on May 24,2007,and a confirmation effluent sample was collected on May 25,2007. The GTF was then shut down.VOCs were not detected in the confirmation effluent sample,and the GTF was restarted for continuous operation on May 29,2007. The plant electrician visited the GTF on May 31,2007,and installed time-delay relays at both extraction wells. The purpose of the time-delay relays is to prevent the extraction pumps from"hammering" on and off because of rapid fluctuations in the GTF radio signals. If the pumps stop because of external interference with the GTF radio signals,the time-delay relays direct the pumps to remain off until they have observed a consistent radio signal for a specific period of time. The pumps will then restart. The time-delay relays were initially set for a delay period of one minute. Beginning in early June 2007,excessive noise was observed on the GTF autodialer phone line. AT&T performed troubleshooting on June 14,2007, and detected a problem with the phone line. AT&T successfully repaired the phone line on June 15,2007. During a site visit on June 15,2007,a very slow drip leak was observed at the influent header pipe,and both extraction wells were cycling on and off at approximately the same time.The leak was located adjacent to the air stripper,and came from a threaded,plugged connection to the former acid injection system.The GTF continued operating until it was shut off on June 16,2007.The threaded plug was replaced on June 16,but the slow drip leak continued.The section of header pipe where the leak occurred was then replaced on June 16.The GTF remained off to allow the pipe solvent cement to cure. The GTF was restarted on June 18,2007. During an inspection of the GTF on June 25,2007,a leak was discovered at the EW-2 wellhead pressure gauge, and EW-2 was turned off. The leak occurred through the handle of a ball valve located directly beneath the pressure gauge. Some water leaked onto the access road adjacent to EW-2,but none of the leaking water entered the stormwater ditch opposite EW-2 or Littlejohn Creek. The ball valve was replaced and EW-2 was restarted on June 26,2007. An acid washing of the air stripper packing material is scheduled for the week of July 9,2007. This routine maintenance procedure removes mineral deposits,thereby improving the efficiency of the treatment system. Additional troubleshooting and repairs of the GTF radio controls are scheduled for the week of July 23,2007,to eliminate the interference and intermittent extraction well cycling that have affected the treatment system. The additional troubleshooting and repairs will include the following steps: • Installing new receivers equipped with built-in signal strength meters at both extraction wells • Verifying radio signal strength at both extraction wells RDD/071990021(NLH3536.DOC) 3