2009 Volume 39 Issue 4 Pages 249-258
This study aimed at evaluating the efficacy of anaerobic methane fermentation on shochu wastewater treatment and collecting the performance data for this system. The performance data studied include Chemical oxygen demand (CODcr) removal efficiency, methane production rate (MPR) and biogas production rate (BPR). Shochu wastewater contained 43, 000mg/l and 36, 800mg/l as total CODcr and suspended solids, respectively. Approximately CODcr removal efficiency of 98% could be achieved after 120h of fermentation in a batch reactor. The optimal biogas production was attained at the shochu wastewater to seed ratio of 1:4 (v/v). Undiluted shochu wastewater sample gave the best results indicating that its dilution is unnecessary. Initial material pH value of 6.5 to 7.5 for the shochu wastewater-seed mixture was effective and the pH outside this range resulted in reduced biogas production. Methane (CH4) content in biogas was on average 65.5% regardless of the initial pH value, with exception of pH 5.5 where no CH4 gas was detected. The BPR of 0.95l/l d and MPR of 0.43l/l d were realized with undiluted shochu wastewater at 1:4 (v/v) shochu wastewater to seed ratio. A large fraction of organic matter was effectively degraded.