Dye is one of the main harmful industrial waste, mainly from the dyes and dye intermediate production industries, made up of a variety of products and intermediate crystalline mother liquor, the loss of material in the production process and scouring the ground water and other components.
Dye industry of our country with a small number of features mostly intermittent operation intermittent discharge of waste water, water quality varies greatly. Dye production processes is long, low yield, high complicated components and concentrations of waste water (COD-1000~10 mg/l) and color depth (500~50 million). Organic components in wastewater mostly aromatic and heterocyclic compounds-matrix, with polar groups and colorant. Wastewater also contains more of the raw materials and by-products, such as halogens, nitro compounds, such as aniline, phenol, and inorganic salts such as NaCl, Na2SO4, n a2S. That dye production varieties, and toward anti-light solutions, development of resistance to oxidation, bio-oxidation, making dye wastewater treatment more difficult. Treatment of dye waste water difficulties: a COD is high, BOD/COD is small, poor biodegradability; second, high colority and complicated components. Relationship between COD removal and bleaching, bleaching more difficult.