Application status of RO membrane

RO membrane description

In recent years, the environmental protection standards set by the government have become increasingly strict, and the contradiction between supply and demand of global water resources has gradually intensified. The application and development of reverse osmosis membrane technology in the field of water treatment has ushered in new opportunities. It has good applications in water treatment fields such as domestic sewage, textile printing and dyeing industry wastewater and landfill leachate.

Domestic sewage contains a large amount of nitrogen and phosphorus elements, bacteria, viruses and organic matter. At present, reverse osmosis membrane technology is mainly used in advanced treatment of urban domestic sewage, reclaimed water plants, and reuse of reclaimed water. The traditional sewage biochemical treatment effluent is filtered, adsorbed, disinfected, etc., and does not pay attention to the desalination process. The domestic sewage treatment project of a certain plant adopts "coagulation → sand filtration → ultrafiltration" as the reverse osmosis pretreatment process, and uses a computer to simulate various technical indicators of the reverse osmosis project. The results show that the quality of the reverse osmosis effluent reaches the level of reused water standard.

The wastewater in the textile printing and dyeing industry has high chroma and high toxicity, and direct discharge will cause serious damage to the water environment. This kind of wastewater has low biodegradability, so it cannot be treated by traditional activated sludge method. After using reverse osmosis membrane technology combined with other processes, it can treat pollutants in the water and realize the recycling of wastewater.

Petrochemical enterprises consume a lot of water, which is used for product production, flushing and wastewater treatment, especially in cooling units. Water needs to be reduced and recycled. In Jiangsu, China, a petrochemical plant's cooling water recycling project using coagulation and ultrafiltration (UF)-reverse osmosis (RO) processes has been operating well for a long time.

The disposal of landfill leachate has become one of the most challenging environmental problems. Conventional methods cannot effectively treat leachate due to high levels of organics and ammonia nitrogen and a host of other complex impurities. Compared with physicochemical or biochemical methods, reverse osmosis has been regarded as an important replacement process.

RO membrane expectation

However, during the membrane filtration process of RO membrane, it will cause the phenomenon of membrane flux decrease, retention rate decrease and operating pressure increase, that is, membrane fouling. Aggregation and inorganic precipitation four. In the actual application process, these four reasons work together to lead to the occurrence of membrane fouling. However, at present, improvement measures have been proposed especially for biological fouling. By monitoring the pollutants in the influent, the fouling potential of the influent can be predicted; the fouling status of the membrane modules can be monitored to obtain real-time information on the fouling of the membrane surface. Then it is controlled by influent water pretreatment, operation management, membrane chemical cleaning, membrane modification and biological treatment. However, the research work on membrane fouling is still continuing, and it is hoped that there will be an effective solution to membrane fouling in the future.

Reference material:

“Modification of reverse osmosis membrane and its application progress in water treatment”

“Research progress on biofouling monitoring and control of reverse osmosis membranes”