Recent advances and perspectives in the use of conductive materials to improve anaerobic wastewater treatment: A systematic review approached

In recent years, many researches have reported that anaerobic digestion and methane production can be significantly improved with the addition of conductive materials to the process. Despite advances, a number of questions about this strategy remain unsolved, including the mechanism and impact of material properties on methanogenic pathways. In order to provide an update on the current state of knowledge and future application perspectives, this work analyzed some of the most recent studies using conductive materials in the anaerobic digestion of effluents through a systematic review of the literature and statistical analysis, as well as the enriched microorganisms, the influence of the dosage, size and conductivity of the materials used. It was found that the change in the microbial community is associated with the use of conductive material (p < 0.05). Additionally, a slight trend was suggested that millimeter-scale materials appear to be more effective in increasing methane production; in contrast to expectations, it was not possible to find a correlation between electrical conductivity and an increase in methane production, supporting the idea that other properties may also perform important roles in the process and require further research. In general, the use of conductive materials is a promising approach to improve anaerobic digestion and methane production, however, the need for future research was indicated to expand the scale of application of this technology.