AGCO Pollution Index Tester

AGCO Pollution Index TesterDetection and calculation methods:
1. Install the SDI tester at the testing position of the RO system. If the test point is after the preprocessing system, then when testing the SDI value, the RO system should be running normally, otherwise the subsequent test results will be invalid.
2. At the beginning, a 0.45 μ microporous filtration membrane cannot be placed inside the SDI tester.
3. After connecting the tester, open the valve on the tester and let the tested water flow directly through the tester for a few minutes.
4. Close the valve, use tweezers to place a 0.45 μ white microporous filtration membrane (with the bright side facing up) on the membrane box support plate of the tester, and gently press the "0" ring and the membrane box cover. Tighten the plastic screw, but not too tight.
5. Open a portion of the valve, and when water flows through the tester, slowly loosen one or two plastic screws to allow water to overflow the tester and expel the air inside.
6. Make sure there is no more air inside the tester and gently tighten the plastic screws. Open the valve, adjust the pressure of the pressure reducing valve to 0.2MPa (207KPa), maintain this pressure, and close the valve. The pressure must remain constant throughout the entire testing period.
7. Collect water samples in suitable containers. As long as the same capacity is used for each test, the size of the capacity is not important. The capacity can be between 100 and 500 milliliters. Different containers are available, such as measuring cylinders, large mouthed cups, coffee cups, Coca Cola bottles, etc. Generally, it is considered to collect 500 milliliters of water sample.
8. Open the valve, measure the time required to collect 500 milliliters of water sample with a stopwatch, and record it as T (1)=__ seconds. After collection, keep the valve open to allow water to continue flowing out.
9. After 5 minutes, use a stopwatch to measure the time required to collect another 500ml water sample and record it as T (5)=__ seconds. After 10 and 15 minutes, perform the same test again and record it as T (10) and T (15), respectively. After the detection is completed, the SDI value can be calculated. Some water sample data sampling may require continuation up to T (20), T (30), or even T (60), although such water samples are rare.
10. Measure the water temperature. During the entire testing period, the water temperature must be maintained at *.
AGCO Pollution Index TesterThe SDI value is calculated using the following formula:
SDI=100P30/ Tt =100（1-T1/ T2）/ Tt
P30- blockage index at 207kpa inlet pressure
The total testing time (minutes) for Tt is usually T15, at which point P30 is less than 75%. Otherwise, testing T10 or T5 would result in P30 being less than 75%
T1- Time required to collect 500ml water sample initially (seconds)
T2- The time (in seconds) required to collect a 500ml water sample after T1 (usually T15, which is 15 minutes)

So what is a manually measured SDI instrument?
The manual SDI pollution index measuring instrument consists of an inlet pipe, a pressure regulating valve, a pressure gauge, and a membrane replacement filter. When measuring the SDI value, only a stopwatch and a 500ml measuring cylinder are needed for testing. The manual SDI pollution index tester can be installed on site and stored in the toolbox after on-site measurement and testing, or it can be directly fixed at the sample water pipeline with a fixture. After testing, the outlet ball valve can be closed. The manual SDI pollution index tester is small in size and light in weight, but the entire testing process requires personnel to operate it without leaving their hands, which is quite tedious. Sometimes we also refer to this SDI instrument as an online SDI measuring instrument or a portable SDI measuring instrument.

What is SDI instrument:
In the era of rapid development in water treatment, SDI instruments are often needed by our staff. What is SDI instrument? What parameters is the SDI instrument mainly used to measure? What is the SDI instrument mainly used for monitoring? What are the components of an SDI instrument? How to measure with SDI instrument? I believe many procurement personnel will ask these questions. Today, let's discuss it!
Before understanding what an SDI meter is, let's first take a look at what SDI values are. SDI， The English name is Silk Density Index, which we refer to as Pollution Index value, also known as FI (Fouling Index) value. SDI value is one of the important parameters of water quality indicators, which characterizes the content of colloids, dust, sediment, rust particles, and other objects that can block various water purification equipment in water.
The SDI value measures the attenuation of flow velocity through an SDI filter membrane with a diameter of 47mm and a pore size of 0.45um. The attenuation of flow velocity is converted into a value between 1 and 100, which is the SDI value. The lower the SDI value, the smaller the tendency for water to contaminate and block the membrane.

What is SDI?
SDI (Sill Density Index) Pollution Density Index Tester: The Pollution Index (SDI) value, also known as FI (Fouling Index) value, is one of the important parameters of water quality indicators. It characterizes the content of particles, colloids, and other objects in water that can block various water purification equipment. By measuring the SDI value, the corresponding water purification technology or equipment can be selected. According to ASTM method 4189-95, this method is recognized within the industry.
In the process of reverse osmosis water treatment, SDI value is one of the important indicators for determining the inlet water of the reverse osmosis system; 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 operational lifespan of reverse osmosis systems.
The SDI value measures the attenuation of flow velocity through an SDI membrane with a diameter of 47mm and a pore size of 0.45 μ m. The reason for choosing a membrane with a pore size of 0.45 μ m is that at this pore size, colloidal substances are more likely to clog the membrane than hard particles (such as sand, scale, etc.). The attenuation of flow velocity is converted into a value between 1 and 100, which is the SDI value. The lower the SDI value, the smaller the tendency for water to contaminate and block the membrane. Considering both economy and efficiency, most reverse osmosis manufacturers recommend that the SDI value of the reverse osmosis inlet water should not exceed * * 5.
The Millipore SDI analyzer system includes a pressure reducing valve, a 47mm membrane changing filter, SDI membrane, and some necessary valves, connecting pipes, and fittings. The system includes a box of mixed cellulose filtration membranes that meet the requirements of ASTM methods. Using this device, only a measuring cylinder and stopwatch need to be prepared to measure SDI values online.
Measuring cylinder, 500ml, PP, small scale 5ml.
Stopwatch, accuracy 0.2 seconds.

47mm diameter, 0.45 μ m pore size MF Millipore mixed cellulose ester filter membrane, consumables.