Microbial Pathogens in Wastewater Treatment Plants (WWTP) in Hamburg

Abstract

Microbial pathogens are among the major health problems associated with water and wastewater. Classical indicators of fecal contamination include total coliforms, Escherichia coli, and Clostridium perfringens. These fecal indicators were monitored in order to obtain information regarding their evolution during wastewater treatment processes. Helminth eggs survive for a long duration in the environment and have a high potential for waterborne transmission, making them reliable contaminant indicators. A large quantity of helminth eggs was detected in the wastewater samples using the Bailanger method. Eggs were found in the influent and effluent with average concentration ranging from 11 to 50 eggs/L. Both E. coli and total coliforms concentrations were significantly 1- to 3-fold higher in influent than in effluent. The average concentrations of E. coli ranged from 2.5 × 10³ to 4.4 × 10⁵ colony-forming units (CFU)/100 ml. Concentrations of total coliforms ranged from 3.6 × 10³ to 7.9 × 10⁵ CFU/100 ml. Clostridium perfringens was also detected in influent and effluent of wastewater treatment plants (WWTP) at average concentrations ranging from 5.4 × 10² to 9.1 × 10² most probable number (MPN)/100 ml. Significant Spearman rank correlations were found between helminth eggs and microbial indicators (total coliform, E. coli, and C. perfringens) in the WWTP. There is therefore need for additional microbial pathogen monitoring in the WWTP to minimize public health risk.