Effect of operating parameters on rice mill wastewater treatment in an acidogenic chamber and MFC coupled system

Abstract

Acidogenic bioconversion of rice mill wastewater (RMW) into volatile fatty acid (VFA) represents an interesting approach for wastewater valorization. In this study, an acidogenic chamber was coupled with a dual-chambered MFC having a ceramic membrane (AC-MFC). A short hydraulic retention time (HRT) was employed for the two-step anaerobic treatment (acidogenesis and electrogenesis) to prevent the proliferation of methanogens. The effect of pH (5.5–7.5) and HRT (0.5 d–0.75 d) were investigated to understand the influence of operating parameters on the performance of the integrated system. The maximum VFA concentration of 1065.15 ± 5.08 mg COD/L was achieved at pH of 7.5 and HRT of 0.5 d. Under these operating conditions, the activity of acid-forming microorganisms and exoelectrogens improved remarkably, and the power density obtained from the system reached 4.72 ± 0.10 W/m3. The current study reveals an excellent potential for simultaneous RMW treatment and power generation in AC-MFC systems.