A group of unit processes designed to separate, modify, remove, and destroy undesirable substances carried by wastewater from industrial sources. United States governmental regulations have been issued for volatile organic substances, designated priority pollutants, aquatic toxicity as defined by a bioassay, and in some cases nitrogen and phosphorus. As a result, sophisticated technology and process controls have been developed for treating industrial waste-water. It is also necessary to implement better water management and waste minimization practices to reduce waste loads and operating cost of treatment facilities.