Water Treatment 'membrane era'
at present, membrane technology has become an important force in the water treatment industry. More than 90% of membrane materials in China are also used for water treatment. However, the reporter learned that although water treatment has enteredFilm era' However, many experts pointed out that the magical membrane technology can only be combined with the traditional process to improve the function and pass the cost.
urban domestic sewage and industrial sewage are'Twelfth Five-Year Plan'The top priority of environmental protection work. 'Energy saving and environmental protection industry development'Twelfth Five-Year Plan The plan has determined the specific scale targets for sewage treatment and solid waste treatment in the next five years. By 2015, the daily treatment scale of newly added sewage nationwide will reach 90 million tons, compared with'Eleventh Five-Year Plan' The index is doubled, and the scale of upgraded sewage treatment is 50 million tons. In the choice of technical route, membrane technology is an established direction.
Zhou Baiqing, the head of the Department of Water Quality Engineering of Wuhan University, who edited the book 'full membrane water treatment technology', introduced to the reporter, microfiltration, ultrafiltration, reverse osmosis and electric desalination are the four most commonly used membrane separation technologies in the field of water treatment. Compared with traditional coagulation, clarification and filtration technologies, they have many advantages. The problem of water pollution in China is very prominent, and the composition of sewage is complicated. In practical engineering, traditional technology alone often cannot solve the problem, and mastering membrane separation technology is helpful to design a water treatment system with various forms and perfection day by day. However, he also pointed out that membrane technology is completely relied on in water treatment, including a full membrane water treatment process formed by organically combining different membrane processes such as ultrafiltration, microfiltration, reverse osmosis, electrodeionization, etc, it is difficult to realize in production, and the application of pharmaceuticals is inevitable. For example, coking wastewater that is difficult to treat also needs biochemical treatment.
Zhou Baiqing believes that the development trend of water treatment technology is the intersection and integration of new and old technologies, thus realizing the advantages and avoiding disadvantages. For example, he said that organic wastewater has complex components, high concentration and salt content, high color and toxicity, and some are difficult to biodegrade, especially for human health. 'Three'(Carcinogenic, teratogenic, mutagenic) Organic pollutants, even if the concentration in water is less than 1×10- At 9 o'clock, it will still seriously endanger human health. It is difficult to make the effluent discharge up to standard by a single treatment process. The existing process must be integrated.
many experts said that membrane technology should be treated dialectically: On the one hand, it is indeed advanced; On the other hand, it should also be integrated with other technologies, and the traditional water treatment process is still very useful.
Huang Huayao, director of Xuzhou Water Treatment Research Institute, believes that although the application conditions of membrane technology are relatively harsh, for example, the particle diameter in water is not more than 5 microns, however, it has the most advantages in the treatment of sewage with high salt content, and so far there is no other better way to treat sewage with high salt content. However, he also pointed out that the membrane method does not save water. He also said that sewage treatment is a systematic project, with a systematic approach and no universal technology. A variety of processing technologies have their own advantages and disadvantages. Only the joint application technology content is higher, and the processing scheme is more perfect.
Ren Qingchun, chairman of Beijing ziguangyitian Environmental Engineering Technology Co. , Ltd. further introduced to the reporter that reverse osmosis membrane plays a leading role in water treatment, and the theoretical water recovery rate is 75%. Judging from the survey results of hundreds of users across the country, in actual operation, the finished water rate of desalted water is only 55% ~ 60%, only a small part of the waste water over 40% is used for spraying or other purposes in coal plants, and most of it is still discharged. Some users are distressed about the 40% waste water discharged in vain. In order to improve the reuse rate, a reverse osmosis device is added to recycle it, but nearly 20% of the concentrated water is still discharged. Ren Qingchun told reporters that there is no more economical and applicable technology for zero emission of enterprise sewage. If membrane technology is used, the treatment cost per ton of water is as high as about 7 yuan, which is not economical.
zero discharge of sewage requires efficient removal of pollutants and deep desalination. In view of the high cost, high water quality requirements and poor system operation stability of membrane technology, experts agree that membrane technology needs to be combined with traditional treatment technology to pass the economic barrier, in order to solve the problem of deep treatment of recycled water and realize the recycling of water resources.