Comparison of disinfectants for drinking water: chlorine gas vs. on-site generated chlorine

The feasibility of on-site generated chlorine (OSG chlorine) as an alternative disinfectant to gas was evaluated in terms total organic carbon (TOC) removal, disinfection efficiency, biofilm control, by-products (DBPs) formation, decay rate, and volatility. Chlorine decreased the pH treated water by -0.1 per mg/L free available (FAC) while OSG increased + 0.06 mg/L. with more hypochlorite ion (OCl-) at higher less effective inactivation suspended bacteria TOC removal but remained distribution system longer controlled formation effectively than gas. DBPs not significantly different from that except for reduction Haloacetonitriles. Hypochlorous acid (HOCl) volatile OCl-, indicating lower volatility FAC chlorine-treated water. Two types systems, “Mixed oxidants” hypochlorite, did show any significant difference disinfection, rate (paired t-test, p = 0.40, 0.11 ~ 0.70, > 0.42). A synergy effect oxidants other cannot be expected use “mixed a treatment plant.