Bio-hydrogen Production From A Combined Process Of Dark And Photo Fermentation By Mixed Bacteria From Anaerobic Sludge

With the development of the human civilization and the further expansion ofthe industrial production, the energy shortage became prominent which caused bythe indiscriminate use of fossil fuels, while the environmental pollution problemcaused by the burning of fossil fuels also became the focus of attention. Both of theenergy and environment issues promoted researchers at home and abroad to studyand develop renewable energy. Hydrogen, as the most ideal clean energy in21stcentury, was considered as the most value of research, development and utilizationalternative energy. At present, hydrogen production was mostly depended on oil,coal and natural gas, and that further increased the consumption of non-renewableenergy. With the in-depth research of the action of microorganisms and the biomasssources, the potential of the biological hydrogen production had gradually beendeveloped, and the bio-hydrogen production technology has also become a hotresearch spot.In this paper, the influence of the anaerobic sludge pretreatment methods to thehydrogen production results were researched firstly, we selected the acid treatment,alkali treatment, heat treatment and combined treatment to treat the anaerobic sludgeand screening bacteria. In the dark fermentation hydrogen production equipment, theaimulated organic wastewater were used as the fermentation substrate, anddetermined the best combined pretreatment methods through compared the variables,such as the biogas volume, hydrogen content and hydrogen yield.The results showed that the sludge heated40min at80℃and dipped24h atpH3.0was used in the dark fermention process, the hydrogen content reached up to85%and the hydrogen yield reached1.867mol-H2/mol-glucose.Compared the bacteria screening by used the common photo fermentationsubstrate (Bacteria1) and the dark fermentation liquid (Bacteria2), and used the twokinds of bacteria in the photo fermentation hydrogen production process, the resultsshowed that, the bacteria2had the better capacity of hydrogen production, thedominant strain had the obvious advantages of hydrogen production, the hydrogen yield could reach8.42mol-H2/mol-glucose. And then the DGGE technology wasused to analysis the two kinds of bacteria, the results showed that, Bacteria2weremainly Rhodopseudomonas sp., Rhodopseudomonas palustris strain,Porphyromonadaceae bacterium, these bacteria had a great contribution to thehydrogen production capacity of the photo fermentation system. At last, the dark andphoto fermentation processes were connected to build a two-stage hydrogenproduction system, and the hydrogen yield could reach3.63mol-H2/mol-glucose.