ASTM D4189-95(2002)

Standard Test Method for Silt Density Index (SDI) of Water

SCOPE
1.1 This test method covers the determination of the silt density index (SDI) of water. This test method can be used to indicate the quantity of particulate matter in water and is applicable to relatively low (1.0 NTU) turbidity waters such as well water, filtered water, or clarified effluent samples. Since the size, shape, and nature of particulate matter in water may vary, this test method is not an absolute measurement of the quantity of particulate matter.
1.2 This test method is not applicable for reagent grade water Types I, II, and III of Specification D 1193, or effluents from most reverse osmosis and ultrafiltration systems.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 14-May-1995
• ICS: 13.060.70 - Examination of biological properties of water
• Technical Committee: D19 - Water
• Drafting Committee: D19.08 - Membranes and Ion Exchange Materials

Relations

• Replaces: ASTM D4189-95 - Standard Test Method for Silt Density Index (SDI) of Water
• Effective Date: 15-May-1995
• Replaced By: ASTM D4189-07 - Standard Test Method for Silt Density Index (SDI) of Water
• Effective Date: 15-Jun-2007
• Referred By: ASTM D4195-23 - Standard Guide for Water Analysis for Reverse Osmosis and Nanofiltration Application
• Effective Date: 15-May-1995
• Referred By: ASTM D6529-22 - Standard Test Method for Operating Performance of Continuous Electrodeionization Systems on Feeds from 50 μS/cm to 1000 μS/cm
• Effective Date: 15-May-1995
• Referred By: ASTM D4188-17 - Standard Practice for Performing Pressure In-Line Coagulation-Flocculation-Filtration Test in Water
• Effective Date: 15-May-1995
• Referred By: ASTM D8002-15e1 - Standard Test Method for Modified Fouling Index (MFI-0.45) of Water (Withdrawn 2024)
• Effective Date: 15-May-1995

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D 4189–95 (Reapproved 2002)
Standard Test Method for
Silt Density Index (SDI) of Water
This standard is issued under the fixed designation D 4189; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4.2 The SDI is calculated from the rate of plugging.
1.1 This test method covers the determination of the silt
5. Significance and Use
density index (SDI) of water. This test method can be used to
5.1 The SDI can serve as a useful indication of the quantity
indicate the quantity of particulate matter in water and is
of particulate matter in water.
applicable to relatively low (<1.0 NTU) turbidity waters such
5.2 The SDI can be used to determine effectiveness of
as well water, filtered water, or clarified effluent samples. Since
various processes such as filtration or clarification used to
the size, shape, and nature of particulate matter in water may
remove particulate matter.
vary, this test method is not an absolute measurement of the
5.3 The SDI has been empirically correlated with the
quantity of particulate matter.
fouling tendency of some water treatment equipment such as
1.2 This test method is not applicable for reagent grade
reverse osmosis devices.
water Types I, II, and III of Specification D 1193, or effluents
5.4 The SDI may vary as a function of water temperature,
from most reverse osmosis and ultrafiltration systems.
and values obtained at different temperatures may not neces-
1.3 This standard does not purport to address all of the
sarily be comparable.
safety concerns, if any, associated with its use. It is the
5.5 The SDI will vary with the membrane filter manufac-
responsibility of the user of this standard to establish appro-
turer. Thus, SDI values obtained with filters from different
priate safety and health practices and determine the applica-
membrane manufacturers cannot be comparable.
bility of regulatory limitations prior to use.
6. Apparatus
2. Referenced Documents
6.1 SDI Assembly, as schematically described in Fig. 1. All
2.1 ASTM Standards:
wetted parts should be made of high-quality stainless steel or
D 1129 Terminology Relating to Water
2 plastic to prevent contamination by corrosion products. Do not
D 1193 Specification for Reagent Water
usereactivematerialssuchascarbonsteelorcastiron.Suitable
D 3370 Practices for Sampling Water from Closed Con-
2 filter holders, designed to withstand an operating gage pressure
duits
3 of 350 kPa (50 psi) can be obtained from suppliers of
E1 Specification for ASTM Thermometers
membrane filters.
3. Terminology 6.2 Membrane Filter, 47 mm in diameter, gridded, and with
a mean pore size in the range 0.45 6 0.02 µm, inclusive. Use
3.1 Definitions—For definitions of terms used in this test
only filters that are packaged in the same orientation.
method, refer to Terminology D 1129.
6.3 Graduated Cylinder, 500-mL capacity.
3.2 Definitions of Terms Specific to This Standard:
6.4 Stopwatch, graduated in hundredths of a minute.
3.2.1 silt density index (SDI)—an index calculated from the
6.5 Thermometer, liquid-in-glass, suitable for measuring the
rate of plugging of a 0.45-µm membrane filter.
temperature of the water sample; capable of being read to
4. Summary of Test Method
within6 1°C and conforming to the requirements as prescribed
in SpecificationE1.
4.1 Water is passed through a 0.45-µm membrane filter at a
constant applied gage pressure of 207 kPa (30 psi), and the rate
7. Procedure
of plugging of the filter is measured.
7.1 Assemble the apparatus as shown in Fig. 1 and set the
pressure regulator at 207 kPa (30 psi).
This test method is under the jurisdiction of ASTM Committee D19 on Water
7.2 Before installing the membrane filter, flush the water to
and is the direct responsibility of Subcommittee D19.08 on Membranes and Ion
be tested through the apparatus to remove entrained contami-
Exchange Materials.
Current edition approved May 15, 1995. Published July 1995. Originally nants. For sampling, follow the procedure given in Practices
published as D 4189 – 82. Last previous edition D 4189 – 94.
Annual Book of ASTM Standards, Vol 11.01.
Annual Book of ASTM Standards, Vol 14.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 4189–95 (2002)
NOTE 6—If the initial size was not 500 mL, use the same sample size
as used in 7.7.
NOTE 7—The pressure must remain at 207 6 7 kPa (306 1 psi)
throughout the test.
NOTE 8—Thewatertemperaturemustremainconstant(61°C)through-
out the test. This is necessary because flow rate changes by about 3 %/°C.
7.9 After completion of the test, the membrane filter may be
retained for future reference.
8. Calculation
8.1 Calculate the silt density index (SDI ) as follows:
T
t
i
1 2 100
F G
% P t
30 f
SDI 5 5
T
T T
where:
%P = percent at 207 kPa (30 psi) feed pressure,
T = total elapsed flow time, min (usually 15 min, see
Note 9),
FIG. 1 Apparatus for Measuring the Silt Density Index
t = initial time required to collect 500 mLof sample,
i
s, and
tf = time required to collect 500 mL of sample after
D 3370. Discrete samples can be used with appropriate pres-
...