Membrane Technologies Used In Wastewater Treatment Of Pulp And Paper Industry

1. Advantages of Membrane Separation Technology

• It can be operated at normal temperature without phase change
• Concentrate and separate simultaneously
• No need to add other substances, and does not change the nature of the separated substances
• Good operating environment, simple operation and convenient maintenance
• Energy saving and environmental protection, no secondary pollution
• Low equipment investment and small floor space
• High processing efficiency

2. Main Membrane Technologies Used in Wastewater Treatment of Pulp and Paper Industry

The application of membrane separation technology to zero-discharge wastewater technology has obvious technological advancement and investment economy. It plays a strategic role in the reform of industrial technology in the 21st century and is considered to be one of the most promising high-tech.

The use of membrane separation technology to treat integrated papermaking wastewater so that it can be reused can greatly reduce the use of clean water. It is feasible in terms of reducing the cost of paper mills and environmental protection.

3. Process of Membrane Separation Technology to Achieve Zero Discharge of Pulp and Paper Industry Wastewater

Jiuwu High-Tech's Papermaking Wastewater Zero Discharge Process Package adopts multiple process modules such as pretreatment + membrane integration + evaporation and crystallization, which can realize full reuse of complex system wastewater. This technology is widely used in paper industry wastewater treatment, printing and dyeing wastewater treatment, oily wastewater treatment, metallurgical wastewater treatment, chemical industry wastewater treatment, zero discharge of concentrated brine in power plants, etc. The core advantages of this technology package are:

• Independent research and development
• Realize the reuse of reclaimed water, and the quality separation of salt and dry mud
• Turn waste into treasure and realize 100% waste water reuse
• The quality of produced water is good, meeting the requirements of production reuse
• Practice of multiple 10,000-ton demonstration projects

The quality of the effluent after the wastewater is treated by Jiuwu High-Tech's Papermaking Wastewater Zero Discharge Process Package:

3.1 Application of Ultrafiltration Technology

Jiuwu Hi-Tech has completed a demonstration project of zero discharge of 40,000 tons/day pulp and paper industry wastewater. The project is located in the Nantong Economic and Technological Development Zone. The treatment object is the industrial sewage in the development zone. The treatment capacity is 40,000m³/d. The entire water treatment station covers an area of 43 acres, mainly including office buildings, factories, pools, and public green belts. The engineering process package was completed by the designers of Jiangsu Jiuwu Hi-Tech. The design process is: air flotation, ozone activated carbon, ultrafiltration, reverse osmosis, electrodialysis, evaporation. The wastewater is treated and reused in stages through the above process, that is, water treated is supplied to the chemical, paper, pesticide and other enterprises in the development zone. Jiuwu Hi-Tech has undertaken projects other than civil construction.

The ultrafiltration part of Jiuwu High-tech Papermaking Wastewater Zero Discharge Process Package is a very critical treatment section of the entire process package. A total of 28 sets of ultrafiltration equipment were designed. Ultrafiltration is a process of separating wastewater using ultrafine filtration membranes with selective permeation function. At the same time, it is also a membrane separation process driven by pressure difference. Ultrafiltration is generally considered to be a sieve separation process. Driven by the pressure difference, the solvent and small solute particles in the raw material liquid permeate the membrane from the high-pressure liquid side to the low-pressure side. The resulting liquid is generally called the filtrate or permeate, while the large particle group The sub-membrane interception increases its concentration in the filtrate to achieve the purpose of purification, separation and concentration of the solution.

3.1 Application of Reverse Osmosis Technology

The reverse osmosis membrane technology in the process package is mainly for desalination, removing the salt in the water, and preparing pure water for use by surrounding enterprises as production water. The reverse osmosis system includes security filters, high-pressure pumps, reverse osmosis membrane concentration devices and membrane system cleaning equipment.

4. Summary

The project can save 20 million tons of water per year, reduce COD and BOD emissions to water bodies by 1,500 tons per year and 400 tons per year, and recover 15,000 tons of solid salt per year. Pulp and paper pollution affects the healthy and sustainable development of the paper industry, and scientific treatment technologies are needed to effectively prevent and control paper pollution. In the future, membrane separation technology will be the main development trend.