DIGESTER GAS UTILIZATION: IS THE TIME RIGHT FOR ON-SITE POWER GENERATION?

Digester gas is a product of the anaerobic digestion process used at many publicly owned wastewater treatment works (POTWs). In many plants, a portion of the gas is used for digester heating and the remainder is flared. Some plants have installed electric power generation facilities that use digester gas as fuel to produce power and recover heat for digester heating. The electric power thus generated is used at the plant to reduce the amount, and thus the cost, of electric power purchased for the plant. With the cost of electric power steadily increasing, is it time to consider the use of on-site general electricity at more POTWs that operate anaerobic digesters? This paper discusses the criteria for owners and operators of POTWs to use in determining whether on-site generation of electricity would be beneficial for their plants.