Isolation, Characterization, and Identification of Bacteria from Activated Sludge and Soluble Microbial Products in Wastewater Treatment Systems

Abstract

Activated sludge process is the most widely used technology for municipal and industrial wastewater treatment. The microbial community of activated sludge is a mixed population of microorganisms containing many species of viruses, bacteria, protozoa, fungi, metazoa, and algae. This review focuses on the recent advances in microbiology of the activated sludge process. The bacterial population in activated sludge system is examined. The standard procedure, medium used, analytical methods and biochemical characterization techniques required for isolation, and identification of bacteria responsible for the key process of wastewater treatment systems (nutrient removal, aerobic, anaerobic, etc.) are discussed in the paper. The effect of seasonal (winter and summer) temperature variations and salinity variation on the bacterial species for wastewater treatment is examined. In addition, soluble microbial products (SMP) is one of the important factors that affects not only microbial activities, but consequently the quality of the effluents from biological wastewater treatment systems; the identification, characterization, significance, and implications of SMP in the context of activated sludge processes are also covered in this paper. Today, most modern wastewater treatment processes rely on the composition and activity of their microbial communities in activated sludges. Recent developments in molecular methods for analysis of the microbial communities have retriggered public interest in the microbiology of activated sludge. Whereas traditional approaches may have reached the point of diminishing returns, the molecular analysis has the potential to increase our understanding of the activated sludge process, and thereby improve the process control.