Effects of blending on surface characteristics of copper corrosion products in drinking water distribution systems

Copper scales formed over 6-months during exposure to ground, surface and saline waters were characterized by EDS, XRD and XPS. Scale color and hardness were light red–brown–black/hard for high alkalinity and blue–green/soft for high SO4 or Cl waters. Cl was present in surface or saline copper scales. The Cu/Cu2O ratio decreased with time indicating an e transfer copper corrosion mechanism. Cu2O, CuO, and Cu(OH)2 dominated the top 0.5–1A° scale indicating continuous corrosion. Cu2O oxidation to CuO increased with alkalinity, and depended on time and pH. Total copper release was predicted using a Cu(OH)2 model.