BIOGAS PRODUCTION FROM CO-DIGESTION OF HORSE MANURE AND WASTE SEWAGE SLUDGE

The biogas yield of horse manure was investigated in batch and semi-continous digesters under mesophilic conditions (35 +/- 2 degrees C) under three stages. The biogas yields obtained in the batch studies fed with horse manure after 35 days of the digestion period were 339 ml/gVS, 374 ml/gVS, 370 ml/gVS, 381 ml/gVS for 0,5 %, 1%,2% and 4% TS contents respectively. In the second part of the batch studies, biogas formation from co-digestion of horse manure with waste sewage sludge was investigated. The horse manure (90%) was mixed with waste sewage sludge (10%) and the biogas production was investigated under two different starting VS concentrations: %4 and %2. The biogas yields after 35 days were 410 ml/gVS and 425 ml/gVS respectively. In the third stage, co-digestion of horse manure (90%) and sewage sludge (%10) mixture was investigated in a lab scale semi-continuous digester with the volume of 5 1. Total solids content was %4. The resulted VS reduction was about 50%.