Mustard Tuber Wastewater Treatment Using Microbial Fuel Cell And The Effect Of Betaine

With the depletion of energy reservers and environmental contamination in the whole world, searching for durable and effective clean energy or recovering useful energy from wastes is an effective approach to alleviate energy and environmental problems in the future. Microbial fuel cell(MFC), utilizing exoelectrogenic bacteria asbio-catalyst, produce electric energy directly from anaerobic oxidation of organic matters present in wastewater. MFC can benefit of both environmental protection and energy resources recovery, so it have been gaining increasinglywide attention as it could.The mustard tuber wastewater, its high-salinity characteristic increases the solution ionic strength. What is more, the wastewater contains sufficient andreadily biodegradable organic matters. Therefore it is attractive to use mustard tuber wastewater as fuel in MFC. On the other hand, mustard tuber wastewater treatment using MFC still in its infant.And there are many limiting elements for the technology to apply commercially.It has been taken into account that two bottlenecks, the activity of microorganisms is suppressed by the high salt and COD in anode chamber effluent is still high.Aimed at these problems,Mustard tuber wastewater was utilized as fuel in the typical dual-chamber microbial fuel cell in this study.The research contents include the following. The effect of increasing anodic Na Cl concentration on microbial fuel cell performance, the auxiliary effect of betaine in improving MFC performance and the performance of a sequential anode-cathode MFC.Salinity plays an important role in performance of MFC.Firstly, the electricity generation performance of MFC at different Na Cl concentrations was investigated.Adding up to 31.2 g/L-1 of Na Cl enhanced the overall performance of the system. Higher Na Cl concentration proved detrimental to the system, increasing the internal resistance and reducing the maximum power production.In addition, the performance of electricity generation has been significantly improved when added glycine betaine with a dosage of 2 mmol/L.Furthermore, the addition of glycine betaine can enhance the ability of anaerobic microbial consortia to adapt to salinity changes, which maintained electricity generation stability.And the operating conditions of anode chamber had a great impact on electricity generation performance of the MFC.Furthermore, the effect of betaine concentrations on high-salinity mustard tuber wastewater treatment and simultaneous electricity generation was investigated.For the performance of electricity generation, the optimum dosage of betaine was 0.1mmol/L. Results showed that theaddition of betaine could improve the activity of electrogenesis bacteria inhigh-salinity environment and reduce the influence on electreigens activity that wassuppressed by the change of water quality. Increasing betaine concentrationcould help to extend duration of cycle. Compared with wastewater without adding betaine, the maximum power density was increased by 40.6% and the internalresistances was decreased by 38.5% with a dosage of 0.1mmol/L. However, theinternal resistances increased as concentrations of betaine increased from 0.1mmol/L to 1.5mmol/L.And the COD removal efficiencies gradually increased with increasing concentrations ofbetaine, while coulomb efficiencies(CE) stabling around 20±2%.The sequential anode-cathode MFC runs steadily and can get good effect of organic matter removal. The effects of aeration rate on electricity generation and organic matter degradation of the MFC were studied.When the DOlevels at cathode was 3.08mg/L, the maximum voltage was 0.333 V.And the maximum power density of MFC was 14.14W/m3, the OCV was 0.505 V and the internal resistance was 159?.When the DOlevels at cathode was of 2.98~3.56mg/L, MFC can maintain a higher electrical energy output.Further increase aeration rate will destruct anaerobic environment of the anode chamber.Result in reducing the electrical energy output of MFC.Increasing aeration rate is beneficial for improving COD removal rate in anode chamber and cathode chamber.COD removal efficiency can reach up to 66.3% above, of which the anode chamber and cathode chamber almost accounted forhalf of the contribution.At a DO of 2.98mg/L, the coulombic efficiency(CE) of MFC reached the peak value(12.38%).