Effective Methods of Chemical Water Treatment for Ensuring Safe Levels of Organic Carbon and Chloroform in Drinking Water

   Introduction: Organic carbon is one of the most important parameters monitored in water treatment, as its presence poses the risk of generation of halogenated organic byproducts during decontamination. Different treatment techniques are used to purify drinking water. Given the dynamic changes in water composition, the issue of selecting the most effective chemical reagents is becoming increasingly important.

   Objective: To establish total organic carbon and chloroform levels during water treatment depending on the reagents used (ammonium sulfate, chlorine, coagulants, or flocculants).

   Materials and Methods: We conducted a four-year monitoring of water temperature and levels of the total organic carbon in the Chusovaya River, during treatment before delivery to the urban distribution network, and calculated long-term and seasonal means. Chloroform and residual chlorine concentrations were measured in drinking water. We assessed water quality and effectiveness of water treatment. The relationship between doses of the reagents and quality parameters was established using correlation analysis.

   Results: The mean level of total organic carbon in the water source was 20.1 ± 1.3 mg/dm3; water treatment reduced it by 32.3 %. The mean chloroform concentration in drinking water was 0.039 ± 0.002 mg/dm³. No interplay was found between reagent doses and total organic carbon levels in drinking water; yet, we observed a positive correlation between total organic carbon levels in the water source, the doses of chlorine and flocculant 2 (a nonionic polyelectrolyte with a bulk density of 660 kg/m³) used for treatment and chloroform levels in drinking water. The use of the aluminum chlorohydrate coagulant, flocculants 1 (a nonionic polyelectrolyte with a bulk density of 830 kg/m³) and 3 (anionic polyacrylamide with a bulk density of 750 kg/m3) demonstrated the best results in removing total organic carbon from water.

   Conclusion: A decrease in total organic carbon concentrations was observed during water treatment with the aluminum chlorohydrate coagulant and flocculants with higher bulk densities being the most effective. A statistical correlation was found between source water quality parameters, doses of chemical reagents used, and the resulting chloroform levels in drinking water.

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