The precautions for using secondary reverse osmosis pure water equipment mainly include the following aspects:
1. Inlet water quality and pretreatment
The inlet water quality should meet the following requirements: temperature 1-45 ℃, pH 2-11, turbidity<1.0 NTU, SDI<4.0, residual chlorine<0.1mg/L. Effective pretreatment must be carried out, including multi-media filters to remove suspended solids, activated carbon to adsorb organic matter and residual chlorine, and softeners to reduce hardness. Insufficient pretreatment can lead to membrane surface deposition, blockage of membrane pores, and reduced equipment performance and service life.
2. Operating pressure and flow control
Reverse osmosis membranes have a specified operating pressure range and must ensure stable pressure. Excessive pressure can damage the membrane, while insufficient pressure cannot achieve the desired filtration effect. At the same time, it is necessary to control the inflow rate well to avoid excessive or insufficient impact on the water production efficiency. When starting or stopping the machine, a large flow rate must be set for flushing to prevent dry burning or contamination of the membrane.
3. Operating temperature management
The water temperature has a significant impact on the performance of reverse osmosis equipment, generally controlled between 5-45 ℃. As the water temperature increases, the viscosity of the water decreases and the flux increases, but it may affect the desalination rate; When the water temperature decreases, the opposite is true. When the water temperature is low in winter, it may be necessary to heat the incoming water.
4. Regular maintenance and cleaning
Regularly replace the filter element to avoid clogging and affecting the quality of the produced water. When the standardized flux decreases by 10-15%, the system desalination rate decreases by 10-15%, or the operating pressure and inter segment pressure difference increase by 10-15%, the reverse osmosis membrane should be chemically cleaned. The cleaning frequency is directly related to the degree of pretreatment. When SDI15<3, the cleaning frequency may be 4 times a year.
5. Other precautions
Avoid dry burning or running without water to prevent damage to the equipment. Control the inlet water temperature and pH value to ensure they are within the appropriate range. Strictly control the ratio of pressure, flow rate, and medication during operation to ensure stable system operation. The lower the amount of wastewater discharged, the better. A low wastewater ratio will accelerate the blockage of the RO membrane.