Dyeing wastewater has high chromaticity, COD in that is mainly composed of small molecules such as dyes, sizing agent and auxilaries. Hollow fiber UF and RO membrane method is usually used in traditional processes: 1. Hollow fiber membrane has almost no removal effect on COD, resulting in subsequent RO organic pollution plugging. 2. With the improvement of environmental protection requirements, the permitted discharge standard of COD in RO concentrated water has dropped from 500 to 200 mg/L, so the traditional process has been unable to meet this requirement.
MEY membrane technology process：
● The decoloration rate of organic separation membrane reached 70-90%, COD removal rate is 50-70%(COD is less than 100 mg/L after biochemistry process was treated by organic separation membrane);
● Extend the cleaning cycle of RO membrane to 1 month or longer;
● Low pressure NF membrane technology was used to replace the RO membrane. COD is less than 200 mg/L of concentrated water could be discharged into the municipal pipe network.