Chapter 20 - Multi-stage constructed wetland microbial fuel cells: A new perspective for potential high-strength wastewater treatment under continuous operation

Abstract

MFC’s have been intensively investigated to harvest energy from different organic sources, but CW-MFC’s were noticed because of their capacity to treat wastewater with better efficiency and bioelectricity generation simultaneously. The presence of plant differs them from sediment MFC, which otherwise consists of similar components and structures. To date, both synthetic and domestic wastewaters have been applied and tested on CW-MFC’s for organic matter removal and energy generation and have been scaled from several to more than 70L. One of the most common problems that researchers face with single-stage CW-MFC’s is its incapability to treat high-strength undiluted wastewater (swine, raw domestic, industrial, etc.) in a continuous operation for a longer period of time. The general recommendation by various researchers stands out on using low to medium strength wastewater for a healthy operation. To counter this, multi-stage CW-MFC’s are being studied for improving the wastewater treatment efficiency and recovering more bioelectricity with the same substrate. The general idea is to trap most of the suspended organic matter in first-stage reactors and provide the second-stage reactors with soluble COD feed and so on, thus achieving enhanced remediation and conversion of the substrate into bioelectricity as all reactors will be functioning simultaneously. For further development of this technology, proper identification of suitable methodology is required which could address various challenges and includes a proper understanding of contaminant removal and energy generation that could enhance the electrochemical properties of the system.