Chemical and Microbiological Quality of Municipal Supply Water in Dhaka South Area, Bangladesh

Abstract

This project aimed to find out the microbiological quality of municipal supply water in Dhaka South area and if the current regime of microbiological quality testing can determine the risk to public health from supply water satisfactorily. Water samples were collected from six different points of the water distribution network of Dhaka’s south locality, starting from the source (Shitalakhyariver, Narayanganj) to Jagannath University, Dhaka. The dominant taxonomic units were isolated using standard culture techniques, followed by biochemical identification, VITEK2 identification, and biofilm-forming potential of each isolate individually and co-cultured with other isolates. Presumptive identification of isolates from the Shitalakhya River revealed the presence of Citrobacter sp., Alcaligenes sp., and Pseudomonas putida. The sample from Saydabad Water Treatment Plant yielded Vibrio mimicus, Pseudomonas fluorescence, and Alcalimonas. The major aerobic bacteria in the water specimen from the community overhead tank included S aureus, Bacillus cereus, Micrococcus sp., Enterococcus sp., Lactococcus sp. Tap water revealed the presence of Escherichia coli, Lactococcus, Enterobacter, Shigella, Klebsiella, Pseudomonas, and Staphylococcus aureus, as well as anaerobic bacteria. Biochemical tests and VITEK2 yielded different results. Potential biofilm formers such as Klebsiella, E. coli, Enterococcus, Aerococcus, Enterobacter, and Cronobacter indicated quality deterioration potential inside the piped water supply system. Alteration in the major taxonomic units throughout the municipal water distribution network and the presence of opportunistic pathogens and biofilm-formers indicate the necessity for an updated water treatment, quality control, and in-line maintenance system.