Removal of Chloroform (CHCl3) from Tehran Drinking Water by GAC and Air Stripping Columns

The harmful substances, defined as trihalomethanes (THMs), were found to be formed during the disinfection of drinking water when chlorine was used as the disinfectant. In this research, the effectiveness of granular activated carbon (GAC) and air stripping (AS) packed column for the removal of chloroform (CHCl₃) (as THMs basic indicator compound in many resources) in range of 50 to 300 μg/L, from drinking water was studied. Pilots of GAC and air stripping columns were designed and set up. The study was carried out for the two cases of deionized and chlorinated Tehran tap water. Also the effects of flow rate, chloroform and TDS concentrations were considered in both treatment systems. Gas chromatography (GC) with electron capture detector (ECD) was used for determination of chloroform concentration in inlet and outlet samples. The obtained data were analyzed by SPSS and non-parametric Kruskal-Wallis method. Results showed a positive correlation between the flow rate and chloroform concentration, and removal efficiencies. The average of variations of removal efficiencies for AS and GAC columns with deionized water samples were, 89.9%, 71.2% and for chlorinated Tehran tap water were 91.2% and 76.4%, respectively. The removal of feed residual chlorine in these columns with 0.5, 0.8 ppm was 100%, respectively and re-chlorination for finishing water was recommended. Results showed AS to be considered more effective in chloroform removal for conventional water treatment plants as a finishing process.