TRIHALOMETHANES REMOVAL FROM DRINKING WATER BY HEATING: A CASE STUDY

Abstract

Trihalomethanes (THMs) specially Chloroform is the most significant and well-known by-products of chlorine disinfection. In light of the alleged carcinogenic effects of THMs in drinking water, the goal of this study was to investigate the consequences of heating the chlorinated water, to lower its THM content, if any, in the drinking water of Dhaka. In this experiment, three individual samples from three separate locations in the same water supply system were investigated in 2019. Chloroform concentrations decreased noticeably (from 42% to 100%) due to heating during the trials. The results revealed that in sample 1, chloroform decreased from 199 to 79.7 20 μg/l (60% removal) after one minute of boiling of water, to 20 μg/l (90% elimination) after two minutes, and finally to 0 μg/l (100% removal) after three minutes. The comparable reductions in samples 2 and 3 were also similar: 70 to 24.5 μg/l (65% removal), 8.5 μg/l (88% removal), and zero μg/l (100% removal) and 153 to 89 μg/l (41.83% removal), 41 μg/l (73.2% removal), and to 40 μg/l (73.86% removal). According to experimental findings, if THM precursors and chlorine residuals are present, there may be a further considerable synthesis of THMs during the heating of drinking water. The generation and volatilization rates of THMs were responsible for the overall fluctuation in THM content in water during heating. Temperature and reaction time were major determinants of the rate of THMs synthesis, in addition to the amounts of THMs precursors and residual chlorine.