Particulates, Metals and TOC
Organics (TOC) adsorb to the surfaces of the resins and membranes. This causes fouling of the active sites. Fouled resins and membranes are inefficient at removing and transporting ions. Stack electrical resistance will increase.
Particulate matter (SDI), colloids, and suspended solids cause plugging and fouling of the membranes and the resin in the chambers. Plugging of resin increases the pressure drop across the module.
Iron and other active metals (e.g., Mn) may catalyze resin oxidation, and may strongly and permanently adsorb to, and reduce the capacity of, the internal resins and membranes. This happens even in sub-ppm concentrations.