Effectiveness of water filters used in the households of Dhaka city

Abstract

This research aims to determine the microbiological quality of tap and filtered water and figure out the efficiency of filters used in the households of Dhaka city. To start, 51 individual samples of tap and filtered water from different areas were collected. The total Viable Count was done by spreading the samples on Nutrient Agar media. According to the study, the minimum TVC count for the tap water sample was 8.6×102 CFU/ml and the maximum was 3.4×105 CFU/ml, whereas the minimum TVC count for the filtered water sample was 5.7×102 CFU/ml and the maximum was 2.26×105 CFU/ml. The criterion for TVC is 1×103 CFU/ml, as stated by WHO and BDS (2009). WHO and BDS (2018) set 1×103 CFU/ml as the benchmark for TVC. Only 8 tap water samples and 15 filtered water samples were found to be within the range of WHO and BD standards based on the TVC values of all 51 samples. The Coliform count was performed after membrane filtration on MFC agar. In total, 51 tap water samples and 51 respective filtered water samples were spread over XLD and MacConkey agar plates. Among the samples, only 2 samples of tap water were not contaminated by E. coli, and only 4 samples of filtered water were not contaminated by E. coli. Next, different biochemical tests were performed to identify the organisms. After that, the research moved on to the Antibiotic Susceptibility Test with 12 different antibiotics. Afterward, a blood agar test and coagulase test were done to find out the pathogenicity of the organisms. These very tests were done to identify the pathogen more closely and precisely and to understand its species. All the suspected organisms showed Alpha hemolysis in the blood agar test, and 74% of organisms showed coagulase-positive results, which is alarming. Finally, to figure out the pathogenic organisms, PCR was performed. After the study of different types of filters, and testing the boiled water, it could be said that the boiled water showed less pathogenicity than some filters with high pathogenic rates.