Enhancing Microbial Electrolysis Cell Generating Hydrogen From Sludge Fermentation Liquid In Low Temperature

The focus on treatment of waste activated sludge (WAS) is increasing, drawing agreat deal of attentions around the world since large amounts of WAS is produced peryear. In China, the government has been allocating a lot of finance to develop new fieldsof WAS applications during the12th“Five-year Programme”. Microbial electrolysis cell(MEC) is characterized biochemical and electrochemical reactions，which makes itselfbe an efficient device recovering energy from WAS.However, there is a bottle neck of enlarge its size to put it into practice becauseMEC produces methane rather than hydrogen when it runs in room temperature. As weknow that Methanogenium is sensitive to temperature. It cannot survive whentemperature is while MEC generating hydrogen is not limited by low temperature.Moreover, it has a wide substance range; therefore, it is a ideal device of WAS treatmentin cold regions where the average temperature of year-round is below10. So in thisdissertation, MEC was sited in low temperature circumstance to produce hydrogen andits efficiency will be explored through auxiliary voltage control and the activitypromotion of anodic bacteria.Optimized by auxiliary voltage (0.6～1.4V), MEC had a best efficiency whenapplied0.8V voltage. The highest SCOD removal rate was58.42%. Efficiency ofhydrogen production was0.16g-/g-SCOD Coulombic efficiency was101.07%.Hydrogen volume was181.5ml. The speed of hydrogen production and energyefficiency were1.21/-reactor/d and252.22%respectively. The order of thecomplex organic consumption was acetic acid>propionic acid>proteins>butyricsoluble carbohydrates. Photographed by scan electron microscope, anode bacteriaclustered together and formed close colony. Through DGGE microbial group analysisand NCBI comparison, Psychrophilus may the dominant bacteria.In the context of optimized voltage, MEC was situated in lower environment (0).Its efficiency was studied through the optimization of exogenous trehalose (ET). It wasfund that SCOD removal rate was40.45%. Hydrogen production was0.078g-/g-SCOD. Coulombic efficiency was58.46%, Hydrogen volume was62.67ml. Thespeed of hydrogen production was0.46/-reactor/d and energy efficiency was203.01%. The order of the complex organic consumption was aceticacid>proteins>propionic acid>butyric soluble carbohydrates. Photographed by scanelectron microscope, anode bacteria loosely grew on the surface of carbon brush.Through DGGE microbial group analysis and NCBI comparison, Psychrophilus may the dominant bacteria. Microbacterium occupied the main part of anode microorganism.