Enhanced Production Of Electricity Microbial Fuel Cells Using Surplus Sludge And Surplus Sludge Reduction By Thermal Oxidation

Microbial fuel cell(MFC)is a new method for utilizing bacteria to generate electrical energy through biomass.Its electrical performance is directly affected by the reactor configuration,electrode materials,and matrix.The substrate can provide the electricity-producing bacteria in MFC.Energy is considered to be the most important factor affecting MFC production.In order to improve the content of substances in the substrate that can be used by the electrogenic bacteria,the experiment uses the thermal oxidation method combined with low temperature pyrolysis and hydrogen peroxide to crack the sludge.Because hydrogen peroxide does not produce pollutants during the oxidation process,The combination of thermal oxidation and MFC technology is worth looking forward to.Therefore,in this experiment,the sludge pretreated by thermal oxidation was used as MFC fuel to analyze the change of properties after sludge hydrolysis,and the effects of temperature,time,pH and hydrogen peroxide dosage on sludge hydrolysis were analyzed.Research and analysis of MFC's power generation performance provides a new method for environmental protection and energy recovery.The temperature increased,the content of SCOD,protein and polysaccharide increased gradually.At 100?,the content of the three increased to the maximum 3897,2230,312 mg/L,is 23,8,20 times of untreated sludge.Respectively.With the prolongation of time,the organic matter in the cells is continuously dissolved and hydrolyzed,so that the SCOD,protein and polysaccharide in the liquid phase are continuously increased,but most of the hydrolysis has been completed within 30 minutes,and the long-term hydrolysis has little effect on the hydrolysis of the sludge.When the pH value is increased,the effect of hydrogen peroxide on the sludge is better,and the oxidizing property is higher than the acidic environment under alkaline conditions.At pH=13,the SCOD content is 3676 mg/L.The dissolution rate of SCOD was larger when the dosage was less than 100 g/kg TSS,and then slowed down;when the dosage was 300 g/kg TSS,the SCOD content reached a maximum of 3687 mg/L,which was the untreated sludge supernatant 16 times the liquid.After continuing to add hydrogen peroxide,the content of SCOD is slightly reduced,and the hydrolysis tendency of proteins and polysaccharides is similar.The thermal oxidation method has the best hydrolysis effect at 80? 30 min,pH=11,300 g·kg-1 TSS H2O2.The content of SCOD,ammonia nitrogen,nitrate nitrogen,protein,polysaccharide and volatile fatty acid,is 17,19,21,2.2,4.6 and 3.8 times of untreated.VSS/TSS decreased from 41.67%to 22.66%,and the content of organic matter in the supernatant was relatively increased,and the sludge was reduced.The good promotion effect lays a good foundation for the subsequent thermal oxidation pretreatment of residual sludge.The pretreated sludge was centrifuged to take the supernatant as a fuel.The electricity production performance of MFC increased with the increase of temperature.At 100?,the output power of MFC increased by 112 mW/m3 and the internal resistance decreased by 430.32 ?.The thermal oxidation method has completed 90%hydrolysis in 30 min.At 90 min,the output power of MFC increased by 176 mW/m3,and the internal resistance decreased by 284.39 ?.With the increase of pH,the content of SCOD,protein and polysaccharide increased to maximum 3676,2587,349 mg/L,protein and polysaccharide decrease at pH=11 and pH=9,respectively.Ammonia nitrogen and nitrate nitrogen decrease with increasing pH,and maximum dissolution at pH=1,is 197,89 mg/L.When pH=1,the maximum output power of MFC increases by 101.9 mW/m3,and the internal resistance decreases by 354.95 ?.When the dosage of hydrogen peroxide is 500 g/kg TSS,MFC has the best power generation performance and the maximum output power increases 125 mW/m3,internal resistance reduced 120.27 ?.The electricity production performance of MFC is not completely consistent with the organic matter content after sludge pretreatment.It is especially obvious when the pH changes.It may be that the increase of pH value leads to severe hydrolysis reaction,the VIA content in the supernatant is low,and the water body is mostly macromolecular organic matter.It is difficult to be directly utilized by the electrogenic bacteria,resulting in low electricity production,but the MFC's electricity production performance is consistent with the organic matter content in the liquid phase when the temperature,time,and H2O2 dosage are changed.In general,the content of organic matter in the MFC matrix has a certain promoting effect on the electricity production performance of MFC.The higher the content of organic substances in the MFC matrix,the higher the nutrients that can be utilized by the electricity-producing microorganisms,and promote to some extent.The reproduction and development of the electrogenic microorganisms increase the electricity production activity of the electrogenic microorganisms and increase the efficiency of electron transfer.