Effluent Treatment Plants (ETP) treat industrial wastewater by removing hazardous chemicals and pollutants, making the water safe for discharge or reuse in factories.  Sewage Treatment Plants (STP) process domestic and municipal wastewater through sedimentation and biological degradation, making it suitable for safe environmental disposal or irrigation.  Mixed Bed Plants are polishing units that produce ultra-pure water by combining cation and anion resins, typically used in pharmaceuticals, electronics, and laboratories.  Demineralization (DM) Plants remove dissolved salts via ion exchange, delivering high-purity water crucial for boiler feed systems, power plants, and chemical manufacturing.