MIEX®DOC process to remove disinfection by-product precursors

In this study, the MIEX®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®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®DOC process in removing the disinfection by-product precursors was dependent on the type and quality of raw water. The MIEX®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%).