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1.0 INTRODUCTION <br />One of the major components of Orange County's (County) integrated solid waste management <br />system is the municipal solid waste (MSW) landfills, MSW contains significant quantities of <br />organic materials that produce a variety of gaseous products when anaerobically decomposed in a <br />landfill. Anaerobic bacteria produces significant quantities of carbon dioxide and methane gas <br />Landfill gas also commonly contains trace amounts of hydrogen sulphide, me captans, vinyl <br />chloride, and numerous other volatile organic compounds Landfill gas represents both an <br />environmental liability and a unique renewable energy resource. The methane component of <br />landfill gas contains energy that can be used to generate electricity, heat buildings, or fuel for <br />industrial processes. Utilization of energy from landfill gas not only aids in the control of local <br />environmental impacts but also avoids consumption of fossil fuels that would otherwise be <br />required to generate an equal amount of energy <br />2.0 ENERGY RECOVERY OPTIONS <br />The primary objective of a landfill gas -to- energy project is to convert landfill gas into a useful <br />energy form such as electricity, steam, supplementary or replacement boiler fuel, or pipeline <br />quality gas. There are several technologies that can be used to maximize the value of landfill gas <br />when producing these energy forms; the most prevalent of which are: <br />• Direct medium -Btu gas use <br />• Power' production /cogeneration <br />Sale of upgraded pipeline quality gas <br />The most advantageous form of energy for a particular landfill will depend upon a number of <br />factors including the existence of available energy markets, process technology requirements, and <br />project development and operation costs. This study focuses on the key elements that determine a <br />project's preliminary economic feasibility and, more specifically, on -site specific design issues <br />related to direct use of gas and /or power production since these are the most common landfill gas <br />recovery options. <br />2.1 Sale of Medium -Btu Gas <br />The simplest and often most cost - effective use of landfill gas is as a medium -Btu fuel for boiler or <br />industrial process uses (e g., drying operations, kiln operations, cement and asphalt production, <br />etc) For this type of project, the recovered gas is piped directly to a nearby customer where it is <br />used in new or existing combustion equipment as a replacement or supplementary fuel. <br />Orange County 1 March 2006 <br />Draft <br />