Feasibility study on treatment of coconut industry wastewater and bioenergy production using microbial fuel cell (MFC)

Coconut processing industries generate a huge amount of wastewater, mainly coconut water from mature coconuts and wash water. Due to the high concentration of organic compounds in waste coconut water, it produces the most pollution even in small quantities compared to the overall effluent generated. Many small/medium-scale processing units discharge waste coconut water directly into the soil or drain it without treatment, polluting soil, groundwater, and surface water. Microbial fuel cells (MFCs) are bioelectrochemical reactors that generate electricity by biodegradation of organic compounds. The present study examines the ability of a dual-chambered MFC, to reduce organic contamination in wasted coconut water. Given the importance for achieving COD removal and bioenergy output, the various influential factors such as KMnO4 concentration as catholyte, catholyte pH, electrode material, and anode configurations were studied. At the best KMnO4 concentration of 2000 mg/L at pH 5, MFC produced a COD removal efficiency of 51.85%, with a maximum power density of 5.5 W/m3 using aluminium electrodes within 102 h of detention period. When the study proceeded with spatially distributed carbon cloth electrodes in anolyte, COD removal efficiency had improved up to 62.72% with a maximum power density of 6.5 W/m3.