A switching control strategy based on alkalinity to optimize biogas outflow in the start-up of an anaerobic digester

This paper deals with the control of the start-up phase in anaerobic digestion systems by using monitoring parameters already implemented that have been coupled to the control law. Methane yield, as well as methane flow rate, and the ratio of intermediate over total alkalinity have been used as control parameters. These measurements have been included in a switching control strategy to drive the process toward a steady state in which biogas production is optimized avoiding accumulation of volatile fatty acids. Experimental validation of this control strategy has been performed from the results obtained using a 358 litter fixed bed anaerobic digester treating industrial winery wastewater