Biogas production from excess activated sludge of seafood processing plant
Weerawit Wongwattanawisit, M.Sc. Student in Biotech., PSU.
Poonsuk Prasertsan, Assoc. Prof., D. of Industrial Biotech., F. of Agro-Industry, PSU.
Udomphon Puetpaiboon, D. of Civil Eng., F. of Eng., PSU.
Corresponding e-mail : ppoonsuk@ratree.psu.ac.th
Grant : Graduate School, PSU.
Presented : The 12th Annual Meeting of the Thai Society for Biotechnology "Biotechnology :
Impacts & Trends", 1-3 November 2000, Kanchanaburi, Thailand
Key words : biogas, excess sludge, seafood, anaerobic treatment
Excess sludge samples were taken from the activated sludge system of a seafood canning factory in Songkhla province. The composition of the excess sludge was determined and found to have pH of 7.58, Biochemical Oxygen Demand (BOD) of 1000 mg/l, Chemical Oxygen Demand (COD) of 5427 mg/l, total solids of 6451 mg/l, toal volatile solids of 200, total suspended solids of 2798
and volatile suspended solids of 29510, the alkalinity was 152 mg/l with the acidity of 150 mg/l. The anaerobic digestion was carried out in four 3.5 L reactors incubating at room temperature (~30oC). The effect of hydraulic retention time (HRT) was studied at the HRT of 20, 10, 5 and 3 days. The results indicated that using HRT of 3 days gave the maximum biogas production (0.057 m3/m3.d), with less amount of biogas (0.041, 0.039 and 0.036 m3/m3.d) from using the HRT of 5, 10 and 20
days, respectively. HRT of 3 days was selected for further studies.
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