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Main points of installation of two-stage reverse osmosis water treatment equipment……

1. Process description The raw water is well water, with high suspended solids content and high hardness. In order to make the incoming water meet the requirements of reverse osmosis inflow, a machine filter is installed with fine quartz sand inside to remove suspended solids and sediment in the water. And other impurities. Adding scale inhibitor system can add scale inhibitor at any time to reduce the tendency of hardness ion scaling in water and prevent concentrated water structure. The precision filter is equipped with a honeycomb-wound filter element with a precision of 5 microns to further remove the hard particles in the water and prevent the surface of the membrane from being scratched. The reverse osmosis device is the core desalination part of the equipment. The single-stage reverse osmosis can remove 98% of salt ions in the water, and the effluent of the second-stage reverse osmosis meets user requirements.

2.  Mechanical filter operation

  1. Exhaust: Open the upper discharge valve and the upper inlet valve to send water into the filter to the upper discharge valve for continuous water inlet.
  2. Positive washing: Open the lower drain valve and the upper inlet valve to make the water pass through the filter layer from top to bottom. The inlet flow rate is 10t/h. It takes about 10-20 minutes until the drainage is clear and transparent.
  3. Operation: Open the water outlet valve to send water to the downstream equipment.
  4. Backwashing: After the equipment has been running for a period of time, due to the trapped dirt, filter cakes are formed on the surface. When the pressure difference between the inlet and outlet of the filter is greater than 0.05-0.08MPa, backwashing should be carried out to ensure smooth water flow. Open the upper drain valve, backwash valve, bypass valve, flush with 10t/h flow, about 20-30 minutes, until the water is clear. Note: After backwashing, the forward washing equipment must be carried out before it can be put into operation.

3. Softener switching cleaning The working principle of the softener is ion exchange. The characteristic of the ion exchanger is that the resin should be regenerated frequently. Pay attention to the following issues when using:

  1. When the hardness of the effluent water quality exceeds the standard (hardness requirement ≤0.03mmol/L), it must be stopped and regenerated; 2. The cationic resin regeneration method is to soak the resin in salt water for about two hours, let the salt water dry, and then use it. Clean water recoils, you can continue to use it;

4. Adding antiscalant system The metering pump and the high-pressure pump start and stop at the same time, and move synchronously. The scale inhibitor is MDC150 produced in the United States. The dosage of scale inhibitor: According to the hardness of the raw water, after calculation, the dosage of the antiscalant is 3-4 grams per ton of raw water. The water intake of the system is 10t/h, and the dosage per hour is 30-40 grams. The configuration of the scale inhibitor: add 90 liters of water to the chemical tank, then slowly add 10 kg of the scale inhibitor, and mix well. Adjust the metering pump range to the corresponding scale. Note: The minimum concentration of scale inhibitor should not be less than 10%.

5. the precision filter The precision filter has a filtration accuracy of 5μm. In order to maintain the filtration accuracy, the system does not have a backwash pipeline. The filter element in the precision filter generally lasts for 2-3 months, and can be extended to 5-6 months according to the actual water treatment volume. Sometimes in order to maintain the water flux, the filter element can be replaced in advance.

6. Reverse osmosis cleaning Reverse osmosis membrane elements are prone to scaling due to the accumulation of impurities in the water for a long time, resulting in a decrease in water production and a decrease in desalination rate. At this time, the membrane element needs to be chemically cleaned.

When the equipment has one of the following conditions, it must be cleaned:

  1. The product water flow rate drops to 10-15% of the normal value under normal pressure;
  2. In order to maintain the normal product water flow rate, the feed water pressure after temperature correction has been increased by 10-15%; 3. The product water quality has been reduced by 10-15%; the salt permeability has been increased by 10-15%; 4. The operating pressure has been increased by 10- 15%. 15%; 5. The pressure difference between RO sections has increased significantly.

7. Storage method of membrane element:

Short-term storage is suitable for reverse osmosis systems that have been shut down for 5-30 days.

At this time, the membrane element is still installed in the pressure vessel of the system.

  1.  Flush the reverse osmosis system with feed water, and pay attention to completely remove the gas from the system;
  2. After the pressure vessel and related pipelines are filled with water, close the relevant valves to prevent gas from entering the system;
  3. Every 5 days Rinse once as described above.

Long-term deactivation protection

  1. Cleaning the membrane elements in the system;
  2.  Prepare the sterilizing liquid with reverse osmosis produced water, and flush the reverse osmosis system with the sterilizing liquid;
  3.  After filling the reverse osmosis system with the sterilizing liquid, close the relevant valves Keep the sterilizing liquid in the system. At this time, make sure that the system is completely filled;
  4. If the system temperature is lower than 27 degrees, it should be operated with a new sterilizing liquid every 30 days; if the temperature is higher than 27 degrees, it should be operated every 30 days. Replace the sterilizing solution every 15 days;
  5. Before the reverse osmosis system is put into use again, flush the system with low-pressure feed water for one hour, and then flush the system with high-pressure feed water for 5-10 minutes; regardless of low-pressure or high-pressure flushing, the system’s product water All drain valves should be fully open. Before the system resumes normal operation, check and confirm that the product water does not contain any fungicides

Post time: Nov-19-2021