"Industrial water problems" spans both the water an industry draws in and the wastewater it discharges. Four representative examples:
Scale and corrosion in boiler/cooling systems — hardness (Ca/Mg) and dissolved gases (O2, CO2) in the intake water foul heat-exchange surfaces and corrode piping, cutting efficiency and shortening equipment life.
Toxic or bio-inhibitory discharge — heavy metals, cyanide or high-strength organics in the effluent can kill the biological process at a downstream municipal plant or the receiving aquatic community.
Thermal pollution — once-through cooling water returned several degrees above ambient reduces the receiving water's dissolved-oxygen capacity and stresses temperature-sensitive species.
Oxygen depletion from organic loading — high-BOD5 discharges (food processing, pulp and paper) consume the receiving water's dissolved oxygen faster than reaeration can replace it.
Other accepted examples include groundwater contamination from leaking storage/impoundments, excessive water withdrawal lowering a local water table, and interference with potable-water treatment processes from an upstream industrial discharge.
