BIOREMEDIATION OF DOMESTIC AND INDUSTRIAL WASTEWATER FOR BIOELECTRICITY GENERATION USING PHOTOSYNTHETIC MICROBIAL FUEL CELL

Abstract

Rapid urbanization, industrialization and modernization are the major key factors behind the increase of energy demands in the last few decades and responsible for deterioration of the quality of freshwater sources globally, which has caused freshwater scarcity in many regions. Discharges from industries containing many pollutants, xenobiotic, high organic load, nutrients and heavy metals into the environment have serious impact on human, animal and aquatic life. In order to resolve these problems, the present study was focused on the technology called microbial fuel cell (MFC) for bioremediation and bioelectricity production using wastewater of distillery spent wash, dairy industry, pharmaceutical wastewater, and municipal sewage. Photosynthetic microbial fuel cell (PMFC), a modified version of MFC, is a promising technology for efficient wastewater treatment, bioelectricity generation and algal biomass production. For this purpose, commercially available microalgae Scenedesmus abundans and bacteria (Bacillus cereus and Pseudomonas aeruginosa) were also used. This thesis focused on the treatment of different industrial wastewaters (distillery spent wash (DSW), pharmaceutical and dairy wastewater) in three different MFCs with single and mixed culture bacteria. The performance of MFC was evaluated considering the major parameters like organic matter removal, voltage generation and biomass production using mixed and single cultures. The maximum COD removal efficiency of 72.5 ± 0.5% from DSW, 85 ± 0.5% from pharmaceutical wastewater and 86 ± 0.5% from dairy wastewater were observed. The results indicate the effective symbiotic relation of Pseudomonas aeruginosa and Bacillus cereus for bioremediation in MFC. The maximum voltage generation of 350.2 ± 0.5 mV in MFC using DSW, 705.4 ± 0.5 mV in MFC using pharmaceutical wastewater and 787.47 ± 0.5 mV in MFC using dairy wastewater were observed. The produced CO2 was transferred from anodic chamber to cathodic chamber for effective utilization in microalgal growth. The maximum algal biomass of 0.52 ± 0.05 g/L from MFC1B+P, 0.82 ± 0.05 g/L from MFC2B+P, 0.95 ± 0.05 g/L from MFC3B+P were observed. First order of kinetic model was performed and as a result, the model was found appropriate.