City of Little Rock Landfill Gas to Energy Project
Little Rock, Arkansas
The City of Little Rock, Arkansas owns and operates a municipal solid waste (MSW) landfill. The facility has been in operation since 1993 and based on the quantity of waste in place, a landfill gas (LFG) collection and control system was required to meet federal air (NSPS) regulations. The city contracted with Johnson Controls, Inc. (JCI) of Milwaukee, Wisconsin, American Environmental Group, Ltd. (AEGL) of Findlay, Ohio, and FTN to initially assess the feasibility of a LFG to energy (LFGTE) project.Because the city had a closed MSW landfill adjacent to the current active landfill, the air regulations required that the closed facility be included in the LFG collection and control system. FTN developed conceptual designs for the LFG collection and control system for the existing landfill and for the old landfill (both as part of the overall system and as a separate system). FTN also developed a conceptual design for the transmission system of the LFG to a nearby industry. FTN prepared estimates of the potential gas production from the existing landfill and the old landfill. To assess the quality and quantity of LFG from the existing landfill, the project team performed a pump (Tier III) test using a skid-mounted utility flare. The project team developed construction and operational costs for the LFG systems (with and without the old landfill). FTN then successfully convinced the Arkansas Department of Environmental Quality that the old landfill should be excluded from the collection and control requirements because it produced a very low amount of LFG, which saved the city approximately $1,000,000. After demonstrating the feasibility of the project, the city contracted with JCI to install and operate the LFGTE system. FTN was contracted with JCI to develop the construction documents, acquire environmental permits for the project, acquire easements for the transmission pipeline, perform construction quality assurance, and provide long-term operation and maintenance services for the system. AEGL was contracted with JCI to install the LFGTE system. The initial collection system includes 10 extraction wells in the first two disposal cells of the existing landfill. The system has been designed to eventually include the entire landfill as it develops. The initial estimated gas production rate is 400 scfm with the potential of 1200 scfm when the entire collection and control system is installed. The collected LFG is dehydrated and then transmitted approximately one mile to a nearby industry that blends the gas with natural gas for use in its kilns.
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