Waste water discharge from industry caused by the use of water to wash and clean, the cooling system, and sewerage of chemical contamination of factory. Some factories discharge waste water consists of organic, inorganic in high quantities. As follow: 1.abattoir, sugar factory, factory production of alcohol. Discharge the water containing organic in high quantities, such as water contaminated with molasses. 2. Industrial chemicals, dyeing factory, factory metal cymbals will discharge the water containing compounds that are toxic and heavy metals into the canal 3.The factory production of caustic soda, shipyard, will leave the water containing mercury. Which cause Minamata disease is a danger to human life and the living in area saen sacp canal.