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Vertical wells will be designed with sampling ports in accordance with 40 CFR Part 60 <br />(Figure 4). The wells are designed for a maximum flow rate of 100 SUM at a nominal <br />vacuum of 10 inches water column. Wells will be adjusted to collect LFG with methane <br />content of between 40% and 55%. <br />3.2.2 Horizontal Wells <br />Horizontal wells will be installed based on a maximum ROI of 400 ft. horizontally and <br />30 ft. vertically. To help reduce air infiltration into the well, a distance of 75 ft. or greater <br />will be maintained between the start of the horizontal well and the side slope or the <br />nearest horizontal short-circuit path. <br />Horizontal wells will be constructed from alternating sections of larger and smaller <br />diameter solid PVC or HDPE pipe, laid in a shallow trench dug into the refuse <br />(Figure 5). <br />3.2.3 Module "I" <br />LFG will be extracted from Module , P' using vertical LFG extraction wells. Plastic <br />(PVC and/or HDPE) laterals will convey LFG from the extraction wells to a perimeter <br />LFG header. <br />3.2.4 Module 1 <br />Horizontal wells are proposed for gas collection in Module 1. <br />Vertical wells may also be installed if needed to supplement LFG control on an as <br />required basis. <br />3.2.5 Lateral Pipes <br />The LFG collection system will utilize lateral pipes for connecting wells to a header. <br />Where the landfill is at or near final grade, the laterals will be placed on the landfill <br />surface. Laterals that connect to horizontal wells or vertical wells that will be buried in <br />refuse will be buried. Wherever possible, lateral pipes will drain into the header pipe. <br />The LFG system will utilize HDPE or other suitable material for LFG piping. To the <br />extent possible, the main LFG collection header will be installed above ground and <br />outside refuse. If installed on native soil, the headers may be installed in trenches with a <br />minimum 0.25% slope. The header system will be sectioned with isolation valves to help <br />facilitate maintenance. Monitoring ports will be installed adjacent to each isolation valve. <br />A tracer wire and polyethylene (PE) marker ribbon will be placed above buried headers <br />for locating purposes and to reduce the chances of accidental damage when digging on <br />the landfill. <br />Foothill Sanitary Landfill 4 Public Works/Solid Waste <br />LFG CS Design Plan County of San Joaquin - March 10, 2005 <br />