Secondary reverse osmosis water treatment equipment installation points

Secondary reverse osmosis device is to force water molecules through the water molecules with the help of pressure through the reverse osmosis membrane has a selective permeability effect, that is, the principle of reverse osmosis water purification, this device for the reverse osmosis device as noted in the different osmotic pressures of various materials, can be greater than the osmotic pressure of the reverse osmosis method for separation, extraction, purification and concentration. Can remove more than 98% of the dissolved salts in water and more than 99% of the colloids, microorganisms, particles and organic matter, etc., to become a modern pure water, space water (ultrapure water) project preferred the best equipment.
I. Process description 
Raw water is well water, high content of suspended solids, hardness, in order to make the water in line with the requirements of reverse osmosis water intake, set up a machine filter, filled with exquisite quartz sand, can remove suspended solids, sediment and other impurities in the water. Add scale inhibitor system can be added at any time to scale inhibitor, reduce the water hardness ion scaling tendency, to prevent the thick water structure. Precision filters are equipped with 5 micron precision honeycomb winding filter element to further remove hard particles in the water and prevent scratching the membrane surface. Reverse osmosis device is the core desalination part of the equipment, single-stage reverse osmosis removes 98% of the salt ions in the water, and the effluent from the second stage of reverse osmosis meets the user requirements.

 Second, mechanical filter operation 
1, exhaust: open the upper discharge valve, the upper inlet valve to the filter to send water to the upper discharge valve continuous water. 
2, washing: open the lower discharge valve, the upper inlet valve so that the water from top to bottom through the filter layer, the inlet flow rate of 10t / h, until the drainage is clear and transparent, it takes about 10-20 minutes. 
3、Operation: open the water valve to the back stage equipment to send water. 
4、Backwashing: After running for a period of time, the equipment forms filter cake on the surface due to the interception of dirt, when the pressure difference between the filter inlet and outlet is greater than 0.05-0.08MPa, backwashing should be carried out in order to ensure that the water passing through is smooth. Open the upper discharge valve, backwash valve, bypass valve, rinse at a flow rate of 10t/h, about 20-30 minutes, until the water is clear. Note: After backwashing, the equipment must be washed before it is put into operation. 

Third, the softener switch cleaning 
The working principle of the softener is ion exchange, ion exchanger use is characterized by: to often regenerate the resin. Use to pay attention to the following issues: 
1, when the hardness of the water quality exceeds the standard (hardness requirements ≤ 0.03mmol / L) must stop using and regeneration;
2, cation resin regeneration method is to soak the resin in brine for about two hours, drain the brine, and then backwash with water, you can continue to use;

VI. Add scale inhibitor system 
Metering pump and high-pressure pump start and stop at the same time, synchronized action. The scale inhibitor is MDC150 from the U.S.A. The dosage of scale inhibitor: according to the hardness of the raw water, the dosage is calculated to be 3-4 grams per ton of raw water. If the system water intake is 10t/h, the dosage per hour is 30-40 grams. 
Configuration of scale inhibitor: add 90 liters of water in the pharmaceutical tank, and then slowly add 10kg scale inhibitor, mix well. Adjust the metering pump range to the corresponding scale. 
Note: The minimum proportioning concentration of scale inhibitor shall not be less than 10%. 

V. Precision filter 
The filtration precision of the precision filter is 5μm. In order to maintain the filtration precision, the system is not equipped with backwashing pipeline. The filter element in the precision filter is generally used for 2-3 months, which can be extended to 5-6 months according to the actual water volume. Sometimes in order to maintain the water flux can also be replaced in advance of the cartridge.

 Six, reverse osmosis cleaning 
Reverse osmosis membrane element due to long-term accumulation of impurities in water, it is easy to scale resulting in a decline in water production, desalination rate is reduced. At this time the need for chemical cleaning of membrane elements.
When the equipment has one of the following conditions, must be cleaned: 
1, in the normal pressure of product water flow down to 10-15% of the normal value; 
2, in order to maintain a normal product water flow rate, after the temperature correction of the feed water pressure increased by 10-15%;
 3, product water quality decreased by 10-15%; salt permeability increased by 10-15%;
4, 10-15% increase in use pressure;
 5, the pressure difference between the RO sections increases significantly. 

VII. Preservation methods of membrane elements:
 1, short-term preservation 
Applicable to reverse osmosis systems that have ceased operation for 5-30 days. At this time the membrane element is still installed in the system's pressure vessel. 
(1) Flush the reverse osmosis system with feed water, and pay attention to completely remove the gas from the system; 
(2) After filling the pressure vessel and associated lines with water, close the associated valves to prevent gas from entering the system; 
(3) Flush the system every 5 days according to the above method. 
2、Long-term out-of-service protection 
(1) Clean the membrane element in the system; 
(2) Prepare sterilization liquid with reverse osmosis output water and flush reverse osmosis system with sterilization liquid; 
(3) Fill the reverse osmosis system with bactericidal solution, close the relevant valves so that the bactericidal solution is retained in the system, at this time should be sure that the system is completely full; 
(4) If the temperature of the system is below 27 degrees Celsius, the system shall be operated with a new biocide solution every 30 days; if the temperature is above 27 degrees Celsius, the biocide solution shall be replaced every 15 days; 
(5) Before the reverse osmosis system is put back into operation, flush the system with low-pressure feed water for one hour, then flush the system with high-pressure feed water for 5-10 minutes; regardless of whether the system is flushed with low-pressure or high-pressure, the system's produced-water discharge valves shall be fully open. Before resuming normal operation of the system, check and confirm that the product water does not contain any biocides.