FUNDAMENTAL-STUDIES ON HYDROGEN-PRODUCTION IN THE ACID-FORMING PHASE AND ITS BACTERIA IN ANAEROBIC TREATMENT PROCESSES - THE EFFECTS OF SOLIDS RETENTION TIME

Effects of solids retention time (SRT) on hydrogen gas production, glu cose degradation and anaerobic bacteria in anaerobic treatment process es were investigated with use of 11,700 mg/l glucose solution as a sub strate. Five series of experiments were conducted at 36 +/- 1-degrees- C. Volatile fatty acids were produced in the order: acetic, n-butyric, propionic and n-valeric with concentration of effluent. Counts of gen eral anaerobic bacteria and acid-forming bacteria in each reactor incr eased with increasing SRT, and counts of genus Clostridium and sulphat e reducing bacteria in the reactor decreased with increasing SRT of th e reactor, Gas production rates and gas composition were investigated to obtain information on energy production. Solids retention time incr eased from 2 to 10 h, hydrogen gas content decreased from 12 to 9%. Th e kinetic constants such as the microbial decay coefficient (K(d)), th e maintenance coefficient (m) and the growth yield for microorganisms (Y(G)) were 4.04, 41.7 and 0.097 day-1, respectively.