Energy harvest from optimized annular single chamber microbial fuel cell (ASCMFC) with novel configuration, which treats chocolate industry wastewater, was investigated. In this study, optimization of operational parameters of the ASCMFC in terms of efficiency water‐soluble organic matter reduction and capability of electricity generation was evaluated. During the experiment, effluent from the anode compartment was examined through current and power density curves for variation in temperature and pH, chemical oxygen demand (COD), and turbidity removal, and substrate concentration. The performance analyzed at different temperature ranges such as 25, 30, 35, and 40°C, which showed 88% increase by uprising temperature from 25 to 35°C. The ASCMFC was used to produce electricity by adjusting pH between 5 and 9 at resistance of 100 Ω. Under the condition of pH 7 power density (16.75 W/m3) was highest, which means natural pH is preferred to maximize microbial activities. Wastewater concentration with COD of 700 and 1400 mg/L were investigated to determine its affection on current production. Reduction of current density was observed due to decrease in wastewater concentration. Significant reduction in COD and turbidity of effluent were 91 and 78%, respectively. The coulombic efficiency of 45.1% was achieved.

Microbial Fuel Cell (MFC) is an efficient system for generating low power where wastewater is substrate for the biocatalyst. In this work, Annular Single Chamber Microbial Fuel Cell (ASCMFC) with spiral anode was fabricated and tested. Carbon cloth and stainless steel 400 meshes were selected as cathode and anode electrodes, respectively. In order to enhance the conductivity of anode, the graphite coating was applied. A 40% platinum as catalyst was used on carbon based cathode in MFC. The carbon cloth was coated with 5% Nafion solution. In fact Nafion acts as Proton Exchange Membrane (PEM) in the fabricated MFC. For the first time, wastewater of Chocolate industry with COD 1400 mg/L was used as substrate in anode compartment. Also a mixture of anaerobic sludge from wastewater treatment plant (Qaem-Shahr, Iran) was introduced into MFC. Maximum voltage obtained in the ASCMFC system was 792 mV in an open-circuit mode. Also, Fabricated MFC operating at 30 •C, the maximum achieved power density using an external resistance of 500Ω was about 4.8 W/m3. The upshots from single chamber MFC were compared to dual chamber MFC. The findings demonstrate that, due to the generated high power density and voltage by the cell, the ASCMFC has a great potential for COD removal and wastewater treatment.