Optimal Control of Iron Release in Drinking Water Distribution Systems Fed with Desalinated Water

When desalinated water enters the existing drinking water distribution systems (DWDSs), the balance between water and scale will be destroyed, resulting in the release of iron and water quality problems, causing “yellow water”. This study investigated the inhibitory effects of pH, alkalinity, and phosphate on iron release and the optimal control condition using pipe section reactors with a response surface. For steel pipe, the optimal condition for iron release control was pH = 8.5, alkalinity = 250 mg/L CaCO3, and phosphate = 0.1 mg/L. For cast iron pipe, the optimal condition was pH = 8.0, alkalinity = 250 mg/L CaCO3, and phosphate = 0.1 mg/L. This study can provide theoretical support for subsequent water supply safety and lay a foundation for the water supply safety of the municipal pipe network.