As we all know, sulphur black dye is an important sulphur dyes for textile especially for denim or jeans yarn dyeing. As the sulhpur black has advantages of low purchasing cost and easy operation, more and more users prefer to buy in bulk quantity.

However, the dyeing wastewater contains more residual indigo dyes. Its chromogenic groups are symmetrical in structure and stable in nature. It is very difficult to be oxidized and cracked.

Sulphur black br is a kind of sulfur dye. The structure of sulfur black varies with the reaction temperature according to the different sulfurization conditions. The 522 sulphur black has certain biological toxicity and is a refractory organic compound.

Because dyeing wastewater contains dyes, slurries, chemical additives and so on, it is very difficult to treat it effectively by a single way. Physicochemical and biochemical methods must be combined in order to meet the discharge standards. The presence of a large number of refractory dyes and toxic sulfides in wastewater makes direct biochemical treatment very difficult, so necessary pretreatment must be done.