Comparative Efficacy of Chlorination Methods in Drinking Water Production

Abstract

Chlorination is a crucial step in eliminating microbial contaminants for drinking water production. Currently, there is a lack of information on the effectiveness of various chlorination methods. This observational cross-sectional study aimed to compare the efficiency of two chlorination methods (i.e., utilizing a dosing pump and manual chlorination) in the raw water preparation process for drinking water production. Water samples and data were collected from 23 drinking water production sites in Tha Bo District, Nong Khai Province, Thailand. After chlorination using both methods, the water samples were analyzed using standard test kits for qualitative testing in terms of free residual chlorine levels according to the standard criteria of 0.2-0.5 ppm (pass/fail) and the presence of microbial contamination (detected/ not detected). The main outcomes were statistically compared between the groups using Fisher’s exact test. We observed that 17 out of 23 water production sites (73.9%) used dosing pumps for chlorination. Interestingly, the percentage of water samples with acceptable residual chlorine content was 94.1% and 16.7% in the sites using dosing pumps and those using manual chlorination, respectively (p<0.05). Similar statistically significant relationships were found between chlorination methods and the presence of microbial contamination (p<0.05). Furthermore, subgroup analysis of sites using underground water as a production resource had also shown consistent findings. In conclusion, this study indicates that the use of dosing pumps is more effective than manual chlorination in the drinking water production process. Therefore, we recommend the widespread adoption of dosing pumps to enhance the quality of drinking water and ensure consumer safety.