Effects of thermobarical pretreatment of cattle waste as feedstock for anaerobic digestion

Lab-scale experiments were conducted to assess the impact of thermobarical treatment of cattle waste on anaerobic digestion. Treatment was at temperatures of 140-220 degrees C in 20K steps for a 5-min duration. Methane yields could be increased by up to 58% at a treatment temperature of 180 degrees C. At 220 degrees C the abundance of inhibitors and other non-digestible substances led to lower methane yields than those obtained from untreated material. In an extended analysis it could be demonstrated that there is a functional correlation between the methane yields after 30 days and the formation rate and methane yield in the acceleration phase. It could be proved in a regression of these correlation values that the optimum treatment temperature is 164 degrees C and that the minimum treatment temperature should be above 115 degrees C. (C) 2013 Elsevier Ltd. All rights reserved.