Catalysis of copper corrosion products on chlorine decay and HAA formation in simulated distribution systems

► Copper accelerated free chlorine degradation by increasing reactivity of natural organic matter (NOM). ► Copper catalysis was affected by pH and copper corrosion product concentrations. ► Surface-associated Cu(II) may also participate into catalysis reactions. ► DCAA formation was consistently predominant, especially at neutral and high pH.