Research On Coupling Technology Of Microbial Fuel Cell-Dewatered Sludge Anaerobic Composting

Dewatered sludge possesses hazardous and potential utilization value. Anaerobiccomposting technology （AnC） with low energy consumption and good fertilizersproperties is the suitable approach for our country, which is limited to be applied dueto the problem of long cycle limites. Taking advantage of the condition that microbialfuel cell （MFC） accelerating the process of anaerobic degradation while recyclingthe electricity from sludge, MFC-AnC was constructed by combining MFC and AnCbioelectrogenesis into AnC system to enhance the sludge degradation and recoverypower simultaneously. The electricity production performance of MFC-AnC, MFCstrengthening anaerobic digestion and effecting composting maturity degree had beeninvestigated.Results confirmed the feasibility of the MFC-AnC to directily generate electricitywith dewatered sludge. After5days startup, cell electricity and anode potential were0.53±0.02V and-0.360.03V. The smallest resistance of79.3Ω appeared at18d withthe maximum power density5.4W/m3, ohmic resistance, charge transfer resistanceand diffusion resistance were1.28Ω,0.53Ω and20.53Ω. Coulomb Efficiency was6.5%. Electricity production bacteria in the anode surface to form dense flora.MFC-AnC system could accelerate the process of anaerobic degradation andhydrolysis. VS degradation rate in MFC-AnC was higher than AnC, the VSdegradation rate was21.8%and16.8%at35d. The acceleration of bioelectrogenesiswas highest at15~20d, and electrogenesis microorganism was active, with the highestrate and efficiency of chemical energy coverted to electricity energy. Bioelectrogenesisintroduced to dewatered sludge anaerobic composting promoted VFAs and SCODproduction, improving the biodegradability, accelerating the hydrolysis of refractoryorganic matter, and eased the limitation of hydrolysis to OM degradation rate. The OMin the sludge was in the form of large molecules. During composting medium, theactivity of MFC-AnC microorganism was significantly higher than AnC, Humic acidand Fulvic acid was material of electrogenesis microorganism. During compostinglater, strength of aromatic amino acid protein fluorophore was in small variations,which was possibly enzymes to be involved in OM degradation.MFC-AnC had better effect of composting than AnC. MFC-AnC could achievedthe effect of volume reduction, the influence of MFC-AnC to sludge pH was weak. There existed high ion concentration in MFC-AnC, with short sludge stable time. Theproduction of MFC-AnC was with GI1.22,0.26higher than AnC. Degree ofmembership to Level1of MFC-AnC was higher than AnC, which indicated that rottendegree of MFC-AnC was better than AnC.