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1 <br />The City of Everett <br />The Floyd & Snider Team Everett Landfill/Tire Fire Site <br />If all other attempts to control a leak are ineffective, localized vacuum extraction wells could be <br />installed to remove LFG from the problem area. <br />Phased active landfill gas controls will be designed and constructed such that, in the future <br />when landfill gas generation rates have dropped to a level that renders the active system <br />unnecessary, the landfill gas controls may be operated as a passive venting system, without <br />vacuum extraction. Evaluation of monitoring data will assist in decision -making regarding this <br />transition to a passive venting system. <br />3.6 CONFIRMATIONAL SAMPLING AT LANDFILL GAS DISCHARGE POINTS <br />This sampling plan pertains only to untreated discharges of landfill gas. Discharges of treated <br />landfill gas would be sampled in accordance with a permit issued by Puget Sound Clean Air <br />Agency (PSCAA). <br />3.6.1 SAMPLING AND INSPECTION PLAN <br />Future development will include active vacuum extraction and discharge of landfill gas to the <br />atmosphere. Future developers could design and construct the vacuum discharge system to <br />require no treatment as discussed in the Brownfield Feasibility Study. The design of such a <br />system would be based on the characterization of the landfill gas as shown in the following <br />Table 1 and estimated landfill gas flows from one or more discharge vents. This data would be <br />modeled using a model like the Industrial Source Complex Model, version 3 (ISC3) currently <br />recommended by USEPA for simulation of concentrations from fugitive emissions and from <br />multiple point sources. The model would determine the location and height of proposed vent <br />stacks so that MTCA cleanup levels and ASIL standards would not be exceeded in ambient air. <br />Model confirmation sampling would be done after construction and an initial period of vacuum ' <br />system operation to verify the assumptions regarding landfill gas characterization and flow rate <br />at each of the constructed vents. The initial period of operation would be no less than 30 days <br />in order to allow the system to stabilize and the gas flow and concentration to normalize. <br />Sampling the system earlier may provide results that are not representative of steady-state <br />operating conditions. <br />A gas sample would be collected from a sample port at each vent location. The sample port <br />would be designed to provide a sample of gas representative of what is in the vent pipe prior to <br />mixing with atmospheric air. The collected sample would be analyzed for the constituents listed <br />in Table 1. The flow rate through the vent would also be measured. <br />1 <br />1 <br />FAprojectslCOEvBR Everett Landfi111PDF maker - final docslCompliance Compliance Monitoring and Contingency Plan <br />Monitoring Plan\CMCP 1 1-10-OO.doc p 9 9 Y <br />FINAL - March 2001 Page 3-10 <br />