Rapid Start-up Of Ethanol Type Fermentation System For Hydrogen Production From Organic Wastewater And Bioaugmentation

Biohydrogen production is a new technology which accords with the strategyof continuous development because of its prominent advantage of cleanness andhigh efficiency. Among the ways of biohydrogen production, biohydrogenproduction from fermentation is more prominent than biohydrogen production fromphotosynthesis because of its stability and ability of hydrogen production. Theethanol type of biohydrogen production from fermentation regarded as the optimalone for the biohydrogen production from fermentation process. Therefore, it wasinvestigated the rapid start up of ethanol type of fermentatitive hydrogen productionand effects of bioaugment on hydrogen production, in order to provide fermentativehydrogen production for industrialization.The difference of hydrogen production in ethanol type and butyrate typefermentation with continuous stirred tank reactor (CSTR) using molasseswastewater as organic substrate was investigated. It was also explored how torealize the quick start up ethanol type fermentation. The CSTR reator was opratedwith VSS of17.7g/L, temperature of35°C, HRT of6h. The results showd thatethanol producing bacterial was inhibited least when pH was3.2in the reactor andthe activity of ethanol producing bacterial restored faster compared with otherbacterial. Therefore, it was concluded that the anaerobic fermentative hydrogenproduction system could form ethanol type fermentation in11d with influent CODdecreased from4000mg/L to2000mg/L and the assistance of pH.Utilizing the adsorption performance of granular activated carbon, aerobiccultivated sewage sludge was self-immobilized as biological carriers. A completelymixed bio-film process for hydrogen production was developed by the combinationof biological carriers and continuous stirred tank reactor. In the long timecontinuous operation, hydrogen producing ability and ecological factors underdifferent organic wastewater acidogenic fermentation types were obtained. Butyricacid fermentation and ethanol fermentation were feasible in the pH ranges4.4~4.7,4.0~4.2, respectively; while ORP ranges were-200~-350mV,-330~-350mV,respectively. The reactor with ethanol fermentation achieved a maximum hydrogenyield rate of3.9m~3/(m~3·d) while hydrogen content was56%, superior to other fermentation types. To simulate load impact in actual operation, COD organicloading rate was reduced to12kg/(m~3·d) from40kg/(m~3·d) and promoted to28kg/(m~3·d) after7days. Although the pH value once drops to3.2during fiercefluctuations, the pH value ascended to4.5and gross gas production raised30%withthe hydrogen content promoted to48%from17%when the normal substrate supplywas restored. It is indicated that the completely mixed bio-film hydrogen productionreactor has good buffer performance and operational stability.Optimal biological enhanced control parameters and efficient strain dosingtechnology for continuous flow fermentation hydrogen production process aredetermined by implementation of bio-enhanced hydrogen for CSTR system by usingefficient hydrogen strains. The results demonstrated that, when the system wasstabled at OLR of12kg COD/m~3·d, and the inoculation quantity of R3was5%, theaverage biogas production capacity and the average hydrogen production capacitywere improved12.9%and18%, respectively. Moreover, the composition of thefermentation products and operational stability were improved.