Microbial Functional Diversity Decreases with Sewage Purification in Stabilization Ponds

The performance of the sewage purification system is constantly raising a challenge to the global wastewater treatment industry. The main perspective of the purification process depends largely on the microbial metabolic activities of the system. Thus it is very important to examine the status of microbial metabolic potential in order to understand the efficacy of sewage purification . In this context, the current study focuses significantly in investigating the metabolic status and functional diversity of microbial community that is involved in sewage purification process at East Kolkata Wetland (EKW). On further investigation into the context, it was observed that the microbial load of the municipal wastewater decreases with due course of the purification process at the stabilization pond. To obtain an in-depth view of the metabolic status and the functional diversity of the microbial community involved in sewage purification process, the metabolic potential of the microbial community was examined by Average well colour development and the microbial functional diversity was examined by Shannon diversity Index (H) at different phases of its purification. The result showed that the metabolic potential of the involved microorganisms is markedly distinct at different stages of sewage purification process. The Multivariate analysis (cluster analysis and Principle Component Analysis) of the different microbial communities involved in the sewage purification process clearly reveals that there are significant variations in their metabolic spectrum. In addition to the metabolic potential of the microbial communities, the functional diversity in sewage decreased with concomitant reduction in Biological oxygen demand, a key indicator of biodegradable organic matter in sewage. Thus the current study reveals the decreasing pattern in functional diversity with the progression of sewage purification in the stabilization pond at EKW.