Experimental Research On Hydrogen Production Through Anaerobic Fermentation Of Organic Wastewater In UASB Reactor

In the paper acclimating anaerobic hydrogen-producing microorganisms seeded with anaerobic granular sludge of some sewage plant in Upflow Anaerobic Sludge Blanket (UASB) reactor was studied. We can adjust and control the un-biological factors e.g. pH, HRT (Hydrolic Retention Time), to realize the transformation from mixed microbe community to the superior hydrogen-producing microbe groups. In the prodecure the gas production rate and composition (hydrogen, methane), volatile fatty acids (VFA), sucrose concentration and CODcr concentration in the reactor and outflow were investigated, and effects of different sodium ion and ammonium concentration on the production of hydrogen by static anaerobic fermentation of sucrose disposed by anaerobic hydrogen producing sludge are studied to seek the conditions and laws of acclimating anaerobic hydrogen-producing sludge ,and the instructions of realistic engineering of acclimating anaerobic hydrogen-producing sludge.The results were concluded from the procedure of the change from producing methane to producing hydrogen:1. pH was controlled at about 7.0,return flow (rate) and COD volumetric loading were adjusted, the aim of producing hydrogen wasn't reached.2. pH was the important un-biological factor during anaerobic hydrogen-producing fermentation.When pH was about4.1~- 4.3, the sucrose concentration of the inflow of UASB reactor was 5000mg/L,HRT was 16h, COD volumetric loading was 26.0kgCOD/(m3-d), the sludge loading was 0.13kgCOD/(kg-VSS-d),the methane-free biogas comprised from 5.2% to 60.2%, the hydrogen production yield was 3.1LHi/(L-reactor volume d), a specific hydrogen production was 3.2 X 10" LH2/(g-VSS d), a sucrose-hydrogen production yield was 408ml/g-sucrose.3. The minimum sodium ion concentration (<1000 mg/L) had bad impactupon the activity and the ability of producing hydrogen of the microbe. The level of 1000 ~ 2000 mg/L of sodium ion concentration had stimulative action upon the anaerobic fermentation of the production of hydrogen. High sodium ion concentration (8000~ 16000 mg/L) had inhibitory effect on the anaerobic fermentation of the production of hydrogen.4. The ammonium concentration (1200mg/L~2400mg/L) had bad impact upon the activity and the ability of producing hydrogen of the microbe. When ammonium concentration was above 4800mg/L, it had inhibitory effect on the anaerobic fermentation of the production of hydrogen.5. There were significant differences of effect of different sodium ion (ammonium) concentrations on acidogenic products associated with time and sodium ion concentrations.