Conforms and Pathogen Removal Efficiency of Various Municipal Wastewater Treatment Processes in India

摘要

The occurrence and removal of fecal indicators [total coliforms (TC), fecal coliforms (FC), fecal streptococci (FS)] and pathogens (helminthes eggs) in four different types of full scale sewage treatment plants (STPs) including activated sludge process (ASP), extended aeration (EA), upflow anaerobic sludge blanket (UASB) and oxidation ponds (OP) were investigated in India during 2006-2007. All influent samples collected from STPs contained TC from log 7.1-7.5, FC log 6.5-7.1, FS log 5.6- 5.9 and helminthes eggs in the range of 21-57 eggs/L. The reductions in fecal indicators bacteria concentration in UASB, ASP and OP were usually between 2.0- 2.5 log units, whereas, log 3.0 reduction in EA system. UASB incorporating with pond system and OP system were observed more efficient to reduce helminthes eggs concentration at almost 100%, whereas only 97% removal was reported in case of ASP and EA system. In addition to monitoring of indicator organisms, turbidity, SS and BOD was also used as indirect measure of the potential presence of microorganisms. Interrelationship of BOD, SS and turbidity with fecal indicator bacteria concentration in influent and effluent manifest that improvement of the microbiological quality of wastewater is strongly linked to the removal of suspended solids.