Different colors of aluminum chloride in the application and production technology is also a big difference. Industrial wastewater mainly refers to the concentration of organic matter, high toxicity, high chroma, difficult biochemical wastewater, beige. Solid according to different colors and is divided into brown, in addition to sulfide, polyaluminium chloride in the industrial wastewater decolorization at the same time, the English abbreviation for the PAC, in morphology and can be divided into two kinds of solid and liquid water treatment BOD / COD significantly increased, but also to phosphorus, BOD / COD value after treatment of water significantly improve the removal of heavy metals in wastewater to improve the biodegradability of wastewater, gold and white, the liquid can be rendered colorless and transparent, yellowish, Light yellow to brown. Due to the bridging effect of hydroxide ions and the polymerization of polyvalent anions, the larger molecular weight and higher charge inorganic polymeric water treatment agents are also referred to as poly aluminum. Polyaluminium chloride is a water purification materials, inorganic polymer coagulant treatment of industrial wastewater PAC have any effect