Description
Microbial fuel cells were researched utilizing landfill leachate as the substrate. Microbial fuel cell (MFC) technology can benefit both the solid waste industry and contribute to reducing greenhouse gas emissions and dependence on fossil fuels. In a microbial fuel cell, organic matter is oxidized (degraded) by microorganisms and electrons are produced. These electrons flow through wiring and a resistor to produce electrical current and therefore direct electricity (Logan, 2008). This system has no energy input, yet can degrade organic matter and produce an energy output. MFCs can be used to treat landfill leachate while reducing energy needs and producing an alternative form of energy.
Landfill leachate is liquid that infiltrates the landfill system or is produced by the waste within the system. Leachate must be collected and managed to protect the surrounding environment. Leachate can also be re-circulated in an operating landfill to manage the leachate as well as increase biodegradation of waste within the landfill and increase landfill gas production. While many organic constituents in the leachate can be treated through the biological processes within the landfill, ammonia can accumulate and resist treatment (Barlaz et al 2002). Ammonia can be toxic to bacteria and other organisms and inhibit accelerated biodegradation that can result from recirculation. MFCs could be used as a pre-treatment for the leachate prior to recirculation to lower concentrations of constituents, while producing electricity and limiting energy inputs into the system.
Laboratory testing was completed on all microbial fuel cell designs and involved both electrical generation evaluation and leachate characterization. Power density and polarization curves were created using electrical test methods. Temperature, dissolved oxygen (DO), pH, oxidation reduction potential (ORP), and conductivity were all measured along with chemical oxygen demand (COD), biological oxygen demand (BOD), total organic carbon (TOC), ammonia, alkalinity, nitrite, nitrate, sulfate, total phosphorus, phosphate, chloride, sulfide, and a suite of metals. Influent and effluent levels were measured for each cycle of the MFCs to determine percent difference. A microbial analysis was also completed on the landfill leachate and biofilm that formed on the anode of the MFC.
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