ABSTRACT
This chapter focuses on the application of biofilm and biogranule based systems for textile wastewater treatment. It presents dye removal from synthetic and real wastewaters by biofilms under aerobic, anaerobic and sequential anaerobic–aerobic conditions. Biofilms are microbial communities enmeshed in a self-produced extracellular polymeric substances matrix formed on a substratum. Both substratum-grown biofilms and self-immobilized granular biofilms are attractive for the treatment of dye wastewaters. Most dyes were considered to be non-degradable and non-transformable by microorganisms under aerobic conditions. Decolourization of dyes under anaerobic condition is initiated by azoreductase-catalysed reduction or by cleavage of azo bonds resulting in formation of aromatic amines. Presence of a wide variety of organic, inorganic and heavy metal contaminants at different proportions makes the biological treatment of real textile wastewater more challenging. Aerobic treatment is very effective for removing chemical oxygen demand from textile wastewaters.
