Electricity Generation from Waste Tropical Fruits - Watermelon (Citrullus lanatus) and Paw-paw (Carica papaya) using Single Chamber Microbial Fuel Cells

Abstract

Tropical fruits are often in abundance when they are in season with most of them ending up in dumpsites as wastes due to lack of technological processes and industries to convert the excess harvest into other useful forms. This study was aimed at converting these huge fruit waste into useable energy using a Single chamber Microbial Fuel Cell (SMFC). Different weights (1kg, 2kg, 4kg, 6kg, 8kg, 10kg, and 12kg) were used in this study for 7weeks with each weight per week. A digital multi-meter (Model: DT 9205A) connected to the SMFC was used to determine the voltage generated by the different weights of the fruit waste. The maximum voltage of 139.5mV and 222.9mV was generated by the 12kg substrate for watermelon and paw-paw respectively. Power densities generated for watermelon and pawpaw were 0.0955mW/cm and 0.2452mW/cm 2 respectively. For watermelon, the value of r(0.976) and paw-paw (0.957) shows that the relationship between voltage and power density is significant. Results from the physicochemical analyses, showed that the highest values for pH, BOD, DO and conductivity was recorded from the 12kg substrate. The medium was mostly acidic for both fruits throughout the study. The DO and BOD values obtained showed that the medium was favorable for microorganisms to proliferate thereby resulting in the high amount of electricity generated. The results from this study have shown that a single chamber MFC is capable of generating electricity from waste tropical fruits. It is therefore recommended that a proper program be initiated to harness this vast resource to augment the epileptic and dearth of electricity supply in our urban and rural areas.