In the last couple of decades, microbial fuel cells (MFCs) have gained importance because of its ability to generate electricity from renewable and carbon-neutral energy sources, such as wastewater. The occurrence of simultaneous biological and electrochemical processes to facilitate the electron transfer mechanism increases the process complexity. Considerable experimental and modeling techniques have been carried out to identify the different processes involved and their relative effect on electricity generation to improve the performance of the MFCs for practical applications. Among the various statistical modeling approaches, the design of experiments (DoE) is used as a robust tool to determine the relationship between variables influencing the performance of the MFCs and to perform optimization of configuration and operation of the MFCs. It has several advantages over the one-factor-at-a-time (OFAT) methodology, in terms of time and resource management as well as obtaining relevant information. This review illustrates the most popular experimental designs used in MFC-related studies. It is expected that the paper will encourage researchers to incorporate this method into their experimental studies to ensure high-quality research output.

Global industrialization has led to an alarming level of release of hazardous and toxic metals in water bodies. Disposal of wastewater containing heavy metals can have adverse impacts on human health, as well as on other components of the environment. The various conventional treatment processes used to date have many disadvantages, such as high amounts of sludge generation, chemical requirements, and cost. Bioelectrochemical systems can overcome these disadvantages and can generate renewable energy or valuable chemicals out of these wastes. Bioelectrochemical systems are processes that can convert the chemical energy derived from oxidation of waste into electrical energy. This chemical energy is derived by the microbial population present in activated sludge. This paper reviews the studies conducted on the three bioelectrochemical processes, namely a microbial fuel cell (MFC), a microbial electrolysis cell (MEC), and a microbial desalination cell (MDC), to treat industrial wastewater rich in heavy metals.