A comparative analysis of organic substrates from industrial wastewater streams for enhanced electricity production using a double chamber microbial fuel cell (DCMFC)

Abstract

This study investigates the startup sequence of a Double Chamber Microbial Fuel Cell (DCMFC) for the treatment of diverse industrial wastewater streams, including biorefinery, dairy, and mixed sources. It presents a comprehensive startup and calibration procedure for the essential electrical components, utilizing MATLAB-SIMULINK to establish typical resistance calibration curves and correlate measured electrical parameters with expected values. This approach enables a robust experimental startup protocol for the DCMFC under psychrophilic and thermophilic conditions. The study explores the impact of fundamental operating parameters on determining the experimental Hydraulic Retention Time (HRT) of the DCMFC. Specifically, it examines the effects of catholyte type (Phosphate buffer) and three distinct organic substrates: dairy wastewater, biorefinery wastewater, and mixed substrates (50% v/v dairy). Electricity production is evaluated in terms of voltage yield (mV), Columbic efficiency (CE) (%), and overall growth yield (Y). The study also assesses the COD (Chemical Oxygen Demand) mass balance component's influence on COD removal efficiency to establish a viable operating HRT during the startup phase. Key findings include startup experimental voltage yields of 145.2 mV for biorefinery, 85 mV for mixed wastewater, and an impressive 357 mV for dairy wastewater. Columbic efficiencies of 0.92%, 0.77%, and 0.02% were respectively achieved. Furthermore, the study reveals a viable experimental HRT, ranging from 72 to 96 hours, for both biorefinery/mixed and dairy/mixed wastewater sources, facilitating startup electricity generation and efficient removal of organic contaminants. These findings contribute to the advancement of sustainable wastewater treatment and bioelectricity generation, offering valuable insights for practical applications.