การเพิ่มประสิทธิภาพการผลิตก๊าซชีวภาพจากของเสียอุตสาหกรรมเอทานอลโดยการเติมโลหะไอออน

Abstract

The objective of this study was to investigate the optimal feeding regime of trace element on biogas production from bio ethanol waste water aiming to increase process stability and biogas production efficiency. Experiment was performed in lab-scale continuous stirred tank reactor having volume of 10 liters under anaerobic digestion condition at the organic load rate of 0.50 - 7.42 kgCOD/m3•d. The control case without element addition can achieve maximum organic loading rate of 3.30 kgCOD/m3•d before process instability can be seen where volatile fatty acid/alkalinity ratio increased above 0.30 and methane content began to drop from the maximum ratio of 67.7%. Compared with the same digestion with addition of trace elements (TEs) including iron, nickel and zinc directly to the first fermentation stage, the process could handle maximum OLR of 4.94 kgCOD/m3•d and maintained volatile fatty acid/alkalinity ratio below 0.30. In addition, biogas production is also increased to 0.325 ± 0.75 liters per kgCOD added. Day with maximum methane content of 70.6%. The cost of trace element addition is estimate to be is 0.026baht per kgCOD added per day.