Impact of pipeline materials on water quality stability of desalinated seawater in the pipeline network

Desalinated seawater is usually weakly acidic, extremely low in hardness and alkalinity, has poor stability, and is highly corrosive.-Before water enters the municipal pipe network, its stability and safety must be guaranteed. We found that the pipe material has a big impact on the water quality of reverse osmosis (RO) desalinated seawater. Cement mortar lined ductile iron pipe (CMDIP) reduces water corrosion. Desalinated seawater requires regulation to ensure chemical stability. Disinfection should occur before transmission and distribution of posttreatment (PT) desalinated seawater to control microorganism growth to ensure biological safety. The pH, TDS, alkalinity, Ca2+, Mg2+, Cl , and SO42  concentration of PT desalinated seawater effluent varies with original water quality and is less affected by the pipe material or disinfectant dose. Polyethylene pipe (PE) is the hardest of the three pipe types for microorganisms to cling to and grow in. Water corrosion is decreased and water chemical stability can be improved by cement mortar lined ductile iron pipe (CMDIP). The epoxy resin-lined ductile iron pipe (ERDIP) involves organic matter dissolution, and the effluent water has a higher turbidity and DOC, affecting biological stability. We provide technical support for water quality regulations and pipe selection for desalinated seawater.