[Identification of total and fecal coliforms and heterotrophic to Microbiological method and E.Coli O157:H7 to immunological, and real time PCR methods in Isfahan water treatment plant]

ABSTRACT

Total and Fecal coliforms [TC and FC], heterotrophic plate count [HPC], were counted by microbiological method and E.coli O157H7 were detected through immunological and Real time PCR methods in water intake and all of units of Isfahan water treatment plant [IWTP]. The microbial profile including TC, FC, and HPC, were monitored and turbidity and total organic carbon were analyzed in 8 locations of water intake, and unit operation and processes of IWTP, including, inlet, sedimentation, ozonation, and filtration and finished water. Immunological method through anti-serum kits and molecular method of RT-PCR were used to detect E.coli O157H7 in the 8 locations and also the sludge of the sedimentation basin and filters backwash water of IWTP. Survival of E.coli O157H7 in sludge sample of sedimentation basin was indicated by formation of agglutination particles in immunological method and through indicator probes in the RT-PCR method. However, E.coli O157H7 was not detected in water samples of other units of IWTP. The removal percent of TC, FC, and HPC were 59.5, 49, and 54.8% in sedimentation basin; 66, 45.8, and 57% in ozonation; 98.8, 98, and 78.8 in the filtration; and 96, 100, 91% in disinfection, respectively. This study approved the existence of the pathogenic coliform, E.coli O157H7 in the sludge of sedimentation basin. Absent of E.coli O157H7 in the finished water indicates that the existing units of IWTP could eliminate these pathogenic bacteria, before reaching the final units of the plant, including the filters and disinfection