Brewery Wastewater Treatment Using Microbial Fuel Cell

Microbial fuel cell (MFC) can convert the organic in wastewater into electrical energy while achieving the degradation of wastewater. In this study, a single-chamber air cathode MFC and a sequential anode-cathode MFC were constructed. Carbon fiber was used as anode while beer brewery wastewater as substrate, the performance of the MFC, including degradation of wastewater and electricity production, was studied.The single-chamber air-cathode MFC can generate electricity while treating brewery wastewater. When hydraulic retention time (HRT) was 2.13h, a maximum open circuit voltage of 0.578V can be achieved, and the maximum power density was 9.52W/m3 while COD (chemical oxygen demand) removal efficiency could reach 40%. The operating conditions of anode chamber had a great impact on the performance of the MFC.Power output increased gradually with the concentration of brewery wastewater.When COD of the brewery wastewater was 2062 mg/L, a maximum power output of 42.6 W/m3 can be achieved. COD removal efficiency increased with the substrate concentration, but coulomb efficiency (CE) decreased. Moreover, phosphate buffer solution (PBS) can also improve the power output and wastewater treatment of the MFC.When COD of brewery wastewater was 614 mg/L, a basic electrochemical model of the single-chamber MFC was established at HRT of 2.13h. According to the non-linear fitting, it can be concluded that the main factors affecting the performance of MFC is the kinetics of activation and concentration loss, and the entire limiting factor was cathode.The sequential anode-cathode MFC can also combine high brewery wastewater treatment efficiency with electricity generation. When HRT of the whole continuous system was 14.7h, COD removal efficiency can reach 90% above, of which the anode chamber and cathode chamber almost accounted for half of the contribution. At the same time, the open circuit voltage and maximum power output were 0.434 V and 0.83 W/m3 (23.1 mW/m2), respectively. Phosphate buffer solution (PBS) can effectively improve the power output, but had little effect on wastewater treatment efficiency.Studies showed that, it is feasible for MFC to treat brewery wastewater, and electricity generated can reduce the cost of the processing, finally can achieve wastewater reuse.