SDI water pollution tester

SDI water pollution testerOperation method:

1. Close the inlet ball valve of this measuring instrument. 2. Install the measuring instrument connecting screw at the measured position. 3. Open the water inlet ball valve and adjust the pressure regulator to 0.21Mpa. 4. Close the inlet ball valve. 5. Remove the membrane box. (Method for removing the membrane box: Push the outer ring sleeve of the quick connect valve upwards, and the membrane box will automatically fall off. Note: When disassembling, hold the membrane box well to prevent it from falling to the ground and damaging the membrane box. 6. After removing, open the membrane box, take out the "O" ring inside the membrane box, place the 0.45 μ filter membrane on the membrane support plate inside the membrane box, then place the "O" ring in place, cover the membrane box cover, and tighten the compression screw to the appropriate program.). 7. Insert the membrane box into the quick connect valve. 8. Open the inlet ball valve to expel any air bubbles from the filter box, close the inlet ball valve, and tighten the compression screw. 9. Open the inlet ball valve and measure the time t1 required to filter 500ml of water sample at the beginning, allowing it to continue filtering. 10. Measure the time to filter 500ml of water sample at 5, 10, and 15 minutes (note: the pressure must be maintained at 0.21 ± 0.07Mpa throughout the entire testing period). 11. Measure the water temperature (note: the water temperature must remain within a range of ± 1 degrees Celsius throughout the entire measurement period).

Notes:

1. During each test, the pressure should be stable and the pressure fluctuation should not exceed ± 5%, otherwise the test will be invalidated; 2. The selected water sample size should be 500ml, and the time interval between two water sample collections should be 15 minutes; 3. At the beginning, the pollution index (SDI) tester cannot accommodate a 0.45 μ m microporous filtration membrane; 4. Throughout the testing process, the SDI measuring instrument must be kept vertically placed; 5. If the SDI test result is high (SDI>5), repeat the experiment to ensure the accuracy of the result; 6. If the water at the outlet of the tester forms droplets within 15 minutes, it can be determined that SDI>5, and the experiment should be repeated again to ensure the accuracy of the results.

SDI water pollution testerIntroduction:

The Pollution Index (SDI) value is one of the important indicators for determining the inflow of reverse osmosis systems. It is the main means of verifying whether the effluent from the pre-treatment system meets the requirements for reverse osmosis inlet water. Its size is crucial for the lifespan of reverse osmosis operation. SDI calculation formula: SDI=100P30/Tt=100 (1-T1/T2)/T. Among them, 100 (1-T1/T2) is the blockage index PI.SDI testing is based on the initial blockage and pollution mechanism of the membrane in principle. Membrane blockage and pollution are not the dominant pollution mode in practice. In the blockage and pollution stage, time T and T/V are linearly related. SDI can only reflect to a certain extent the speed of particle blockage greater than 0.45um, or the rate of flux attenuation (in the early stage of filtration). Therefore, SDI is not * * used to evaluate the potential pollution level of UF, NF, RO raw water, at least one-sided This has been confirmed by a large number of researchers in years of practice.