Application of membrane technology in industrial wastewater treatment and reuse
Release Time：
2017-12-13
Membrane technology is applied in industrial wastewater treatment and reuse to recover valuable components from wastewater and reuse the permeate, which has been purified, in relevant processes. This saves resources and water while preventing environmental pollution.
The earliest and most mature application in this area is the use of reverse osmosis (RO) or electrodialysis (ED) technology to treat electroplating wastewater, such as wastewater from nickel, chromium, copper, zinc, and tin plating, to recover these metal ions, and the water is reused for rinsing. Due to the high value of chromium and nickel reuse, many countries focus on the treatment of chromium-containing and nickel-containing wastewater. Another application is the use of UF technology to treat electrophoretic painting wastewater, recovering electrophoretic paint (polymer resin), and the water is reused for rinsing. In China, both technologies had industrial applications on a certain scale in the 1970s and 1980s. At that time, domestic cellulose acetate tubular UF membrane devices were mostly used in electrophoretic painting wastewater treatment. Later, cathodic electrocoating developed, and China's development of charged UF membranes could not keep up, so many automobile factories began to introduce foreign charged UF membranes. Cellulose acetate RO membranes were mostly used for nickel, zinc, and tin plating wastewater, while chromium plating wastewater is acidic and strongly oxidizing. Foreign countries mostly use aromatic polyamide membrane materials, while China has used polysulfonamide membranes [26].
The use of UF technology to treat desizing wastewater from the textile industry to recover polyvinyl alcohol and reuse water began to be industrially applied in foreign countries in the 1980s. Large-scale ultrafiltration desizing wastewater plants with a membrane area of nearly 10,000 square meters have been built, with significant economic and environmental benefits. Although there are reports on application research in China, it has not yet been promoted.
Membrane technology for treating dye wastewater has obvious advantages compared with traditional wastewater treatment processes. Research has been conducted both domestically and internationally since the 1970s, but the investment is relatively large. Currently, the anti-pollution ability of membranes is low, and the treatment cost is high, so the application of membrane methods for treating dye wastewater is still limited. It is necessary to find a technically feasible and economically viable treatment process to ensure the recovery and utilization of dyes or permeate, so that wastewater treatment can generate economic benefits. This will be the research direction of membrane treatment of dye wastewater.
The paper industry is one of the largest sources of industrial wastewater. Research on the use of membrane processes to treat this type of wastewater began in the 1970s, and membrane treatment devices of a certain scale have been established in Europe, the United States, and Japan to explore the feasibility of membrane technology in these fields. There are already UF and RO devices available for treating sulfite pulp wastewater.
Japan has many small-scale submerged membrane bioreactors for treating wastewater from various food processing, dairy products, and breweries. China also has engineering examples of using membrane bioreactor technology to treat food processing and chemical wastewater, mostly with a scale of less than 1000 m³/d.
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