The cleaning of the membrane is generally divided into two kinds of physical cleaning and chemical cleaning, and the higher the frequency of chemical cleaning, the greater the damage to the membrane, seriously affected the membrane system life.
The membrane cleaning frequency is closely related to the degree of improvement of the pretreatment measures. The more perfect the pretreatment, the longer the cleaning interval; the other hand, the simpler the pretreatment, the higher the cleaning frequency. The general membrane cleaning is followed by a 10% reduction in the ratio of the freshwater flow that is corrected to the flow rate of the initial 200 h and 10% to 20% of the observed differential pressure. Try to take measures as much as possible when the desalination rate drops. Regularly protected protective cleaning is not sufficient to protect the reverse osmosis system.
Chemical cleaning systems typically include a chemical mixing tank and matched pumps, mixers, heaters, and the like. According to the operating experience to decide (according to each column equipment pressure drop reading and running time curve, or based on water production, fresh water quality and membrane pressure drop, etc.).
Chemical cleaning agents and methods used to be determined according to pollution sources. The following table for reference, but should pay more attention to and application of the experience of the unit. In order to ensure the effect, in the chemical cleaning before the rinse. Rinse before the first step, and then 2 to 3 times the normal flow of water rinse the membrane, by the role of fluid stirring the dirt from the membrane surface from the membrane stripping and washed away.