Biohydrogen from sugar industry waste and sewage

Anaerobic co-digestion of press mud and sewage for biohydrogen production was performed in an upflow anaerobic sludge blanket reactor (20 l). Experiments were conducted under three dilution ratios 1∶7·5 (series I), 1∶10 (series II) and 1∶12·5 (series III) by diluting press mud with sewage and filtering all fibres. Total solids, dissolved solids, suspended solids, volatile solids, volatile dissolved solids, volatile suspended solids, chemical oxygen demand, volatile fatty acid and alkalinity were tested at regular time intervals. Daily biohydrogen produced and hydrogen percentage were also monitored. A maximum biohydrogen yield of 7985 ml/day at the rate of 4990 ml/kg press mud added with a specific biohydrogen production rate of 187 ml/g volatile solids reduced/day was evaluated in series II (dilution 1∶10). A volatile suspended solids/total suspended solids ratio of 0·82–0·92 and a volatile fatty acid/alkalinity ratio of 0·01 were estimated to be the optimum parameters for press mud co-digestion at a pH of 5–6 under ambient conditions.