অ্যাস্টার এসডিআই টেস্ট কিট – সিল্ট ডেনসিটি ইনডেক্স কিট

1. Connect the SDI kit between the micron filter and high-pressure pump.
2. Run the plant at service flow using the raw-water pump only.
3. Close the SDI kit's needle valve completely.
4. Adjust the membrane reject valve to obtain approximately 2 kg/cm² pressure.
5. Place the 0.45-micron filter paper correctly inside the SDI kit.
6. Open the SDI kit needle valve.
7. Fine-adjust the membrane reject valve to maintain 2 kg/cm² on the SDI kit pressure gauge.
8. Place the 500 ml beaker under the outlet.
9. Record the time required to fill the empty 500 ml beaker as T₀.
10. Allow water to continue passing through the same filter paper for 15 minutes.
11. After 15 minutes, place the empty beaker under the outlet again and record the time required to collect 500 ml as T₁₅.
12. Calculate the SDI using the formula below.

SDI Calculation

SDI = [1 − (T₀ / T₁₅)] × 100 / 15

Where:

• T₀ = Initial time required to collect 500 ml
• T₁₅ = Time required to collect 500 ml after 15 minutes

A higher SDI indicates a greater increase in filtration resistance during the test, indicating a higher presence of filterable suspended/colloidal material in the tested water.

Installation

1. Provide a 1/4" BSPM threaded nozzle at the location where SDI measurement is required.
2. Screw the SDI kit's needle valve onto the nozzle.
3. Connect the kit using the quick-release coupling.
4. The installation is then ready for testing.
5. After testing, disconnect the kit and store it safely.

Filter Paper Handling

Handle the filter paper carefully and hold it only by the edges. Particles, fingerprints, or wrinkles on the filter paper can affect the test and result in an erroneous reading.