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past the monitoring ports." Parametrix(1998c)provides a status of <br /> sinkhole monitoring(including thermocouple temperature probes) and a <br /> map showing seven sinkhole locations where water injection probes were <br /> installed to help extinguish subsurface fires associated with sinkhole <br /> subsidence. Thermocouple temperatures over 1,000°F were observed, <br /> indicating active combustion. Liner repairs at sinkhole locations were also <br /> proposed. <br /> Due to failure of water injection at sinkholes to prevent continued <br /> subsurface fires,the County of Hawaii contracted Walker Consultants, <br /> Inc.,to attempt alternative mitigation techniques. Walker recommended <br /> injection of water and liquid carbon dioxide to quench fires,and sealing of <br /> liner leaks with wetted soil. In December 2001,24 carbon dioxide(CO2) <br /> injection probes and 58 eater injection probes were installed. In June <br /> 2003,18 addition CO2 probes were installed. Water and CO2 were injected <br /> episodically from January 2002 through at least January 2004(Walker <br /> 2004). Walker describes"areas of concern" as having methane (CH4) <br /> levels greater than 5 percent and oxygen(02) levels greater than 4 percent, <br /> and therefore prone to combustion. Walker(2004) describes a general <br /> decrease in the extent of"areas of concern"following water/CO2 <br /> injection. The geographic areas of highest concern were the east-center, <br /> north-center and northwest portion of the landfill(Walker,2004). <br /> 1.2 PROBLEM DEFINITION <br /> ERM understands that the Kailua-Kona Landfill continues to support <br /> subsurface waste combustion,with potential associated air emissions of <br /> combustion gases(along with decomposition by-products). A <br /> Supplemental Environmental Project(SEP)is proposed to achieve the <br /> following principal objectives: <br /> 1) Better understand the nature and extent of subsurface fires and <br /> associated gas by-products to facilitate development of effective <br /> mitigation strategies; <br /> 2) Conduct a demonstration of subsurface landfill fire suppression using <br /> a fire-retardant foam; <br /> 3) Extinguish a known area of burning waste material and improve <br /> subsurface conditions at the landfill;and <br /> 4) Develop a plan and cost estimate for extinguishing all existing landfill <br /> fires. <br /> ERM 3 KAILUA-KONA LANDFILL/0061204-3/14/2008 <br />