Carbon steel material printing and dyeing wastewater equipment

The water quality of printing and dyeing wastewater varies greatly depending on the type of fiber used and the processing technology used, and the composition of pollutants varies greatly. Printing and dyeing wastewater generally has the characteristics of high pollutant concentration, diverse types, toxic and harmful components, and high chromaticity. The pH value of general printing and dyeing wastewater is 6-10, CODCr is 400-1000mg/L, BOD5 is 100-400mg/L, SS is 100-200mg/L, and chromaticity is 100-400 times.

But when the printing and dyeing process, the type of fiber used, and the processing technology change, the quality of sewage will undergo significant changes. In recent years, due to the development of chemical fiber fabrics, the rise of silk like fabrics, and the advancement of post printing and dyeing finishing technology, a large amount of difficult to biodegrade organic compounds such as PVA slurry, artificial silk alkali hydrolysates (mainly phthalates), and new additives have entered the printing and dyeing wastewater. Their CODCr concentration has also increased from several hundred mg/L to over 2000-3000 mg/L, BOD5 has increased to over 800 mg/L, and pH value has reached 11.5-12. As a result, the CODCr removal rate of the original biological treatment system has decreased from 70% to about 50%, or even lower.