MIEX®DOC process to remove disinfection by-product precursors

In this study, the MIEX (R) DOC process was applied to test the removal potential of halogenated organic water disinfection by-products (trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, chloropicrin and chloral hydrate) precursors. The experiments were conducted using model and surface water samples. The samples of untreated water and the MIEX (R) DOC process effluent were chlorinated with sodium hypochlorite which resulted in residual free chlorine of 3-5 mg L-1 after 24 h. After this time, the water was analysed to check the presence of chlorination by-products using the gas chromatography method. Subsequently, the formation potential was calculated for each group of halogenated organic compounds. The efficiency of the MIEX (R) DOC process in removing the disinfection by-product precursors was dependent on the type and quality of raw water. The MIEX (R) DOC process showed the highest removal efficiency for trihalomethanes (68%-90%), haloacetic acids (76%-82%) and chloral hydrate (62%-88%) precursors. Lower removal efficiencies were observed for the precursors of haloacetonitriles (42%-72%), haloketones (26%-73%) and chloropicrin (9%-74%).