Misunderstanding of the application of membrane method in water treatment equipment

The current water treatment equipment projects, the use of membrane treatment process a lot, but in the course of the membrane processing for the treatment there are still many misunderstandings, mainly reflected in the following points. Misunderstanding one: membrane water treatment equipment is difficult operating system In fact, membrane method water treatment system operation is highly automated, start and stop, dosing and online washing and other operations can be controlled by the PLC system implementation, you can do unattended, only artificial scheduled inspection dispensing, periodic maintenance cleaning, basic No need to add additional staff. Misunderstanding 2: film fragile easily damaged - Some companies due to lack of experience, design and construction of the membrane system appeared broken film, membrane scrap and other issues, the user mistakenly think that the membrane product is difficult to maintain. In fact, the main problem comes from the two aspects of process design and film itself. Misunderstanding 3: The number of brands and RO than the membrane area and system design According to the different manufacturers of reverse osmosis, the types of reverse osmosis membranes on the market are common: low pressure reverse osmosis membrane, ultra-low pressure reverse osmosis membrane, brackish water reverse osmosis membrane, anti-pollution reverse osmosis membrane, ultrapure water reverse osmosis membrane, Desalination membrane and so on. Many users pay more attention to the number of RO membranes in the membrane reuse system and decide which series of reverse osmosis membranes should be used according to the requirements of the end-user on the desalination rate, the operating pressure, the requirements on the pollution speed and the cleaning frequency, Water quality to determine. In theory, the minimum production capacity of a single 8040 membrane element is 0.46 T / h (using surface water as the inlet water source), 0.80 T / h (using groundwater as the inlet water source), 1.15 T / h Infiltration system of water as a secondary reverse osmosis system of water). When the system water production is greater than the above-mentioned value, the 8040 membrane element can theoretically be used. However, whether or not the 8040 membrane element is used should also take into account factors such as the recovery rate of the system, whether to allow concentrated water to flow back, the system footprint, the pressure vessel cost, and the overall economy of the system. In addition, reverse osmosis water production by the temperature and other factors are also affected. Misunderstanding 4: The greater the number of film the better In a certain range, increasing the number of membranes can improve the water safety of the membrane system and reduce the operating costs. However, when the number of membranes increased to a certain extent, the amount of water evenly spread to the membrane per unit area decreased. The flow velocity of membrane surface under cross-flow filtration was lower than the critical value, and the deposited debris on membrane surface could not be taken away. Water production performance decline. Moreover, the increase in the number of membranes, the amount of flushing water increases, if the amount of flushing water pump and compressed air can not meet the needs of flushing volume per unit area, it is difficult to thoroughly rinse, increase membrane pollution, affecting its water production performance. According to the comprehensive balance of various factors, generally considered more than 5T / h reverse osmosis system using 8040 membrane components more appropriate, 3T / h reverse osmosis system using 4040 membrane components more appropriate, 3 ~ 5T / h reverse osmosis system 8040 or 4040 membrane element can be. Misunderstanding 5: RO membrane must use anti-pollution film Anti-pollution RO membrane is divided into two types: First, the membrane flow channel wider, easy to plug and anti-pollution, this film is generally applicable; the other is through the RO membrane surface modification, the RO membrane was negative, positive Sexual or neutral, based on the principle of repulsion of the same sex, so that specific properties of pollutants is not easy to deposit on the membrane surface, in order to achieve anti-pollution characteristics. The latter anti-pollution play, largely depends on the characteristics of water quality.

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