Bioelectrochemical systems for the treatment of textile dye wastewaters

Hazardous and recalcitrant textile dye containing wastewaters are produced through various textile and dyestuff manufacturing industries causing a major concern of environmental pollution. Therefore, there is a need to develop sustainable solutions to treat textile dye containing wastewaters. The application of bioelectrochemical systems (BES) offers a plausible solution for the energy-efficient remediation of textile dye wastewaters. The textile dyes present in wastewater are treated by biochemical oxidation-reduction reactions in the BES systems which generates clean energy in the form of bio-electricity. A range of electroactive microbial catalysts such as bacteria, microalgae, and fungi have been used in the BESs to treat textile dye wastewater. Electron-consuming microbial electrolysis cells (MECs) and electron-producing microbial fuel cells (MFCs) are the two divisions of BESs frequently used in wastewater treatment. Various configurations of BESs such as dual chamber, air cathode, biocathode, algal, photo-assisted and, sediment MFC systems as well as MECs and photocatalytic electrolysis cells (PECs) have been used recently in the remediation of textile dye wastewaters. The decolorization and degradation of textile dye wastewater can be further enhanced by integrations of BESs with other reactor configurations forming hybrid BESs. Recently, various hybrid BESs such as constructed wetland-microbial fuel cell (CW-MFC), floating treatment wetland-MFC, hybrid aerobic or anaerobic bioreactor-MFC, membrane bioreactor-MFC, MFC-Fenton system, MFC-membrane filtration, photoelectrocatalytic (PEC-MFC) and, other hybrid BES systems are being intensively researched in the remediation of textile dye wastewaters. This book chapter provides a comprehensive overview of working principles, mechanisms of bio-electrocatalysis, electrogenic microorganisms and, operational parameters influencing the performance of BESs in the treatment of textile dye wastewaters. An overview of key challenges, improvements, and the future outlook of BESs for textile dye wastewater treatment is also presented in this chapter.