Energy Recovery From Wastewater Treatment Biogas: Integration of an Anaerobic Digester With a High Temperature Fuel Cell

Wastewater treatment facilities operating with anaerobic digesters produce a methane-rich gas as by-product of the process. In most cases, this gas is released into the atmosphere, thus increasing the greenhouse effect, due to the presence of methane. At the same time, the methane content makes the biogas an interesting source of energy. An efficient energy recovery presents the dual benefits of reducing greenhouse gas emissions and of producing a usable form of energy (typically electric current or heat), using a renewable source of energy, thus diminishing fossil fuel consumption. Due to the high operating temperature, Molten Carbonate Fuel Cells (MCFCs) and Solid Oxide Fuel Cells (SOFCs) present the advantage of being able to operate with a wide variety of fuels, of achieving high energy efficiency and of releasing near-zero emissions. In the present study, the possibility of integrating an anaerobic digester with a high temperature fuel cell is presented. The result of the study illustrates the options, opportunities and the relative benefits and disadvantages related to this energy recovery option.