Microbiology and Biochemistry of Anaerobic Treatment

This chapter deals with biotransformation of nitrogen, sulfur compounds, and methanogenesis during anaerobic treatment processes. Under anaerobic conditions, nitrate, sulfate, and carbonate are the major alternative acceptors of electrons to molecular oxygen for harnessing the energy by way of oxidation of organic compounds present in wastewater. Their availability and interactions affect the nature and efficiency of the treatment process, by way of denitrification, dissimilatory nitrate reduction to ammonium, anammox, sulfate reduction, or methanogenesis. The diversity of the microorganisms involved and the biochemical mechanisms for each of the mentioned process are described. In addition, the importance of redox potential and the interactions involved among these different microbial groups is explained schematically.