SIMULTANEOUS PRODUCTION OF ELECTRICITY AND TREATMENT OF WASTEWATER THROUGH MICROBIAL FUEL CELL

Abstract

Microbial fuel cells (MFCs) can be used to directly generate electricity from the oxidation of dissolved organic matter. but optimization of MFCs will require that we know more about the factors that can increase power output such as the type of' proton exchange system which can affect the system internal resistance. Simultaneous production of electricity (expressed in terms of 'v oltage, and po\er density) and organics removal (in terms o %COD removal) has been studied in batch scale MFC with synthetic glucose-glutamic acid solution FfIct of process parameters such as pH. initial COD on the electricity generation and organics removal have been studied in batch MFC. Optimum temperature. p11 and initial COD values for batch MFC are found to be as 35 °C. ph 1 7 and 1 500 m2/l. respectively. In present investigation a Microbial fuel cell system with a low cost polymeric proton exchange membrane gives the maximum voltage outputs of I 55111V. 78mV and 235.6mV and power densities 5.6mW m/, I .5mW/m2 and 13.57mW /rn2 respectively for initial COD conc.( 1500mg/I), Initial p11(7) and Mediator concentration(.3mM). With an ilR'F of 8-10 days. a steady COD removal efficiency of 85.7%, 83.4% and 84.6% was achieved at an external resistance of 50 Q at optimum values of Initial COD concentration. mediator concentration and Initial p11 difference respectively. For this system the synthetic glucose-glutamic acid (1: I ) solution has been considered because of the facts that these are normally available in the distillery effluents and model compound as substrate is required to understand the MR' process. Optimization and modelling of voltage production and current density was done using Design Expert software version 8.0.7.1 trial. Box-Behnken model using 3 factors (initial COD conc., Initial p11, and mediator conc.) with 3 levels each was used to fix the experimental conditions. Various levels are Initial COD conc. (1000mg/I. 1500mg/I. 2000mg/I), Initial pH. (6. 7. 8) and mediator conc. (0.2111M. - 0.3mM. 0.4mM). Total 17 experimental conditions were obtained to conduct experi rnents