Research On Excess Sludge Degradation By Photosynthetic Bacteria With Microbial Electrolysis Cell

Due to the high volume of excess sludge,it has been a burning question to achieve sludge reduction and resource recycling for waste water treatment plants in China.With the advantages of removing organic components and recycling clean energy simultaneously,microbial electrolysis cells(MEC)are promising techniques to meet the challenges of excess sludge,and hydrogen production by photosynthetic bacteria(PSB)is a research focus on large-scale Bio-hydrogen production field due to its higher substrate conversion efficiency,better light energy utilization and more flexible in utilization of a wide variety of small molecule organic acids.In this research,the attention was focused on the effect of different light intensity and different PSB concentration on excess sludge degradation by MEC with PSB.In this study two control experiments were designed.In the first experiment,the light intensity was set for the variables,which were dark(OLux),natural light(12h OLux+12h 1500Lux),weak light(1500 Lux)and strong light(3000 Lux).For the second experiment,the concentration of PSB in MEC was set for the variables,which were 0,10%,20%and 30%.The water quality detection(Chemical Oxygen Demand(COD),protein and Volatile Fatty Acid(VFA)),gas production situation,remove efficiency of Volatile Suspended Solids(VSS)and coulombic efficiency of energy analysis were used as the detection index.The results show that,in the first experiment,to some extent,the remove efficiency of COD,protein and VFAs increased as the incensement of light intensity,the gas production and the remove efficiency of VSS presented the same situation,but the coulombic efficiency decreased as its incensement.For the second experiment,the remove efficiency of COD,protein and VFAs increased as the incensement of PSB concentration in MEC,the gas production and the remove efficiency of VSS presented the same situation,but the coulombic efficiency decreased as its increasement.By the analysis of chromatography of gas collected from the reactor,the results show that,the production of carbon dioxide and methane was lower and the production of hydrogen was higher,besides,the production of hydrogen increased as the increasement of light intensity and PSB concentration in MEC.The technique of excess sludge degradation by MEC with PSB was a good method,by which the sludge reduction and resource recycling were both achieved.By this research the foundation was laid for subsequent in-depth study of the related fields,which has the certain significance and the social value.