title: Hydrogen production with immobilized sewage sludge in three-phase fluidized-bed bioreactors.
abstract: Municipal sewage sludge was immobilized with a modified alginate gel entrapment method, and the immobilized cells were used to produce hydrogen gas in a three-phase fluidized bed. The hydrogen-producing fluidized beds were operated at different liquid velocity (U(0)) and hydraulic retention time (HRT). The results show that in response to operating liquid velocities, the fluidized-bed system had three flow regimes, namely, plug flow, slug flow, and free bubbling. Pressure fluctuation analysis was used to analyze the hydrodynamic properties in this three-phase fluidized bed when it was under a steady-state production of biogas. With a steady-state biogas production rate (U(g)) of 0.196 mL/s/L, a transition state occurred at a liquid velocity (U(0)) of 0.85 cm/s. As U(0) < 0.85 cm/s, the system was basically a nonhomogeneous fluidized bed, whereas the bed became homogeneous when U(0) was higher than 0.85 cm/s. The fluidized bed can be stably carried out at high loading rates (HRT as low as 2 h). Hydrogen fermentation results show that the maximal hydrogen production rate was 0.93 L/h/L and the best yield (Y(H)2(/sucrose)) was 2.67 mol H(2)/mol sucrose.
authors.affiliation: Department of Chemical Engineering, Feng Chia University, Box 25-102, Taichung 407, Taiwan.
authors.forename: Shu-Yii
authors.initials: SY
authors.lastname: Wu
authors.forename: Chi-Num
authors.initials: CN
authors.lastname: Lin
authors.forename: Jo-Shu
authors.initials: JS
authors.lastname: Chang
mesh_terms: D001711:Biotransformation; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods*; D018914:Cells, Immobilized / Q000502:physiology; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D006859:Hydrogen / Q000302:isolation & purification* / Q000378:metabolism*; D007220:Industrial Waste / Q000517:prevention & control; D012212:Rheology / Q000295:instrumentation* / Q000379:methods*; D012722:Sewage / Q000382:microbiology*; D013696:Temperature; D018508:Water Purification / Q000379:methods
chemical_list: D007220:Industrial Waste; D012722:Sewage; D006859:Hydrogen