Zero Discharge of Printing and Dyeing Wastewater

1. Preface

With the improvement of quality of life, people's demand for clothing, food, housing, and transportation has further increased, and they have higher spiritual needs for bright and colorful clothes and various items. Under these conditions, the printing and dyeing industry is flourishing. But the printing and dyeing industry is a major water user, and the wastewater it produces has high chromaticity but relatively single composition. There are fewer other impurities in the water, and the water quality is good. If certain methods are used, zero discharge can be achieved, which not only reduces environmental pressure but also saves a lot of costs.

2. Disadvantages of Common Solutions

At present, biochemical treatment+ultrafiltration RO is mainly used for water reuse of printing and dyeing wastewater to achieve zero discharge, but this method has two drawbacks.

Due to the fact that the COD of ultrafiltration effluent is usually around 100, the pressure of the RO membrane is relatively high. A water production rate of 70-80% is usually only around 50%, which increases operating costs. Although it achieves zero emissions, it is not conducive to cost savings.

Ultrafiltration effluent with a COD100ppm concentration is not considered a good source of water for RO membranes. The organic content in this type of wastewater can still damage the RO membrane, and long-term use can cause blockage or even damage to the RO membrane. At present, the cost of RO membrane is relatively high, and once damaged, it may cause an increase in environmental drainage pressure, which will not be worth the loss if it affects production.

3. Haipu customized solutions

Haipu Functional Materials Co., Ltd. has developed a special adsorption material and its supporting equipment for efficient treatment of COD. The system can be installed after ultrafiltration effluent, effectively reducing the COD after ultrafiltration and achieving the optimal conditions for RO inlet water. It can effectively protect the RO membrane and improve its water production rate. At present, multiple printing and dyeing companies have entered into preliminary cooperation with us. A printing and dyeing company in Suzhou has used our equipment, and its RO water production rate has increased to over 80%. The original water COD is around 10ppm, and after treatment with special adsorbents, the effluent COD can be below 40ppm, which has a good treatment effect on large amounts of low COD wastewater and low operating costs. Effectively solving the problem of low water production rate of RO membrane, protecting the RO membrane and saving costs, making zero emissions worry free.