The Research On Microbial Electrochemical Systems With Different Cathode Conditions And Excess Sludge Reduction With Energy Recovery

Bioelectrochemical system is a new, energy recovery from substrate. In the 21 st century, energy problem has gradually become the major problem that plagued the people to solve. But microbial electrochemical system provides a new direction to this issue. Bioelectrochemical system mainly includes microbial fuel cells and microbial electrolysis cells. While most of the current urban sewage treatment process was activated sludge process, this method has a good water treatment effect, low capital and operating costs, more tolerance to the impact of hydraulic load. However, this method has a very serious problem, that is, in the treatment of urban sewage, will produce more excess sludge. The traditional excess sludge treatment cost is huge, and it will produce serious environmental pollution. But the bioelectrochemical system can recycle the energy of excess sludge, and it’s operating conditions was more moderate. So the research of bioelectrochemical system of sludge reduction and energy recovery performance is very necessary.This study firstly investigates operation efficiency of MEC under the form of different cathode catalysts of MFC in the different substrate: acetate and excess sludge. The conclusion was the rolling activated carbon cathode catalyst system in MFCs has the best electrochemical performance. At the same time, the removal of CDO, TSS and VSS of excess sludge between the rolling activated carbon cathode catalyst MFCs and the Pt/C cathode catalyst MFCs has no significant difference. Three groups of different cathode catalyst MFCs realized recovering electric energy from the substrate. Although the biological cathode MFCs’ electricity production efficiency is low, but its tolerance to changes in substrate was better. Theoretically, Pt/C catalyst’ performance should be better than the activated carbon catalyst. But the activated carbon cathode catalyst was made by rolling, and Pt/C cathode catalyst was made by coating. Due to better uniformity of the rolling process the activated carbon cathode catalyst performance is better.Then the paper investigates the gas production performance between activated carbon catalyst cube single-chamber MECs and Pt/C cathode catalyst cube singlechamber MECs. The conclusion there is no notably different between them. But taking the cost of Pt/C into account, this experiment adopted rolling activated carbon cathode catalyst as the barrel-type MEC cathode catalytic system. After that, the performance of barrel-type MEC in 2 g/L acetate and alkali pretreatment excess sludge was discussed. In this experiment, we try to optimize the barrel-type MEC’s excess sludge reduction performance, after a comprehensive consideration of the SRT, gas production efficieny and sludge reduction performance, this paper determine the appropriate SRT of barreltype MEC was 16 days.