ASTM D4194-95(2001)
(Test Method)Standard Test Methods for Operating Characteristics of Reverse Osmosis Devices
Standard Test Methods for Operating Characteristics of Reverse Osmosis Devices
SCOPE
1.1 These test methods cover the determination of the operating characteristics of reverse osmosis devices using standard test conditions and are not necessarily applicable to natural waters. Two test methods are given, as follows: SectionsTest Method A-Brackish Water Reverse Osmosis Devices8-13 Test Method B-Seawater Reverse Osmosis Devices14-19
1.2 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.
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Standards Content (Sample)
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Designation: D 4194 – 95 (Reapproved 2001)
Standard Test Methods for
Operating Characteristics of Reverse Osmosis Devices
This standard is issued under the fixed designation D 4194; 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 3.2.6 permeate—that portion of the feed which passes
through the membrane.
1.1 These test methods cover the determination of the
3.2.7 permeate flow rate—the quantity of permeate pro-
operating characteristics of reverse osmosis devices using
duced per unit time.
standard test conditions and are not necessarily applicable to
3.2.8 rejection—that portion of the salt in the feed which
natural waters. Two test methods are given, as follows:
does not pass through the reverse osmosis membrane, ex-
pressed as percent and is equal to (100 % − salt passage).
Sections
3.2.9 salt passage—the ratio of permeate salt concentration
Test Method A—Brackish Water Reverse Osmosis De- 8-13
to feed salt concentration, expressed as percent.
vices
Test Method B—Seawater Reverse Osmosis Devices 14-19
4. Summary of Test Methods
1.2 This standard does not purport to address all of the
4.1 These test methods consist of determining the desalinat-
safety concerns, if any, associated with its use. It is the
ing ability and permeate flow rate of reverse osmosis devices.
responsibility of the user of this standard to establish appro-
They are applicable to both new and used reverse osmosis
priate safety and health practices and determine the applica-
devices.
bility of regulatory limitations prior to use.
5. Significance and Use
2. Referenced Documents
5.1 Reverse osmosis desalinating devices can be used to
2.1 ASTM Standards:
produce potable water from brackish supplies (<10 000 mg/L)
D 512 Test Methods for Chloride Ion in Water
and seawater as well as to upgrade the quality of industrial
D 1125 Test Methods for Electrical Conductivity and Re-
water. These test methods permit the measurement of the
sistivity of Water
performance of reverse osmosis devices using standard sets of
D 1129 Terminology Relating to Water
conditions and are intended for short-term testing (<24 h).
D 1193 Specification for Reagent Water
These test methods can be used to determine changes that may
have occurred in the operating characteristics of reverse
3. Terminology
osmosis devices but are not intended to be used for plant
3.1 Definitions—For definitions of terms used in these test
design.
methods, refer to Terminology D 1129.
6. Reagents
3.2 Definitions of Terms Specific to This Standard:
3.2.1 concentrate, reject, or brine—that portion of feed
6.1 Purity of Reagents—Reagent grade chemicals shall be
which does not pass through the membrane.
used in all tests. Unless otherwise indicated, it is intended that
3.2.2 conversion or recovery—the ratio of permeate flow
all reagents shall conform to the specifications of the Commit-
rate to feed flow rate, expressed as percent.
tee on Analytical Reagents of the American Chemical Society,
3.2.3 desalination device—a single pressure vessel contain-
where such specifications are available. Other grades may be
ing a reverse osmosis element or elements and supporting
used, provided it is first ascertained that the reagent is of
materials.
sufficiently high purity to permit its use without lessening the
3.2.4 device pressure drop (DP)—the difference between
accuracy of the determination.
the feed pressure and the concentrate pressure.
6.2 Purity of Water—Unless otherwise indicated, references
3.2.5 feed—the solution that enters the device.
1 3
These test methods are under the jurisdiction of ASTM Committee D19 on Reagent Chemicals, American Chemical Society Specifications, American
Water, and are the direct responsibilities of Subcommittee D19.08 on Membranes Chemical Society, Washington, DC. For suggestions on the testing of reagents not
and Ion Exchange Materials. listed by the American Chemical Society, see Analar Standards for Laboratory
Current edition approved April 15, 1995. Published June 1995. Originally Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
published as D 4194 – 82. Last previous edition D 4194 – 89 (1994). and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
Annual Book of ASTM Standards, Vol 11.01. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 4194
to water shall be understood to mean Type III reagent con- plastic components, or from feed solutions previously used in
forming to Specification D 1193.
the system. If materials are suspect, thoroughly clean or
degrease or both, before use. All pressurized components
7. Apparatus
whether stainless steel or plastic should be designed based on
7.1 The apparatus for both methods is schematically de-
the manufacturer’s working pressure rating. Review manufac-
scribed in Fig. 1 and Fig. 2. A conductivity meter can be used
turer’s rating for compliance with standard engineering prac-
to determine the salt concentration in accordance with Test
tice.
Methods D 1125.
7.2.2 The reverse osmosis testing apparatus, represented
7.2 Installation:
schematically in Fig. 1 using a centrifugal pump, consists of a
7.2.1 Materials of construction shall be of high-quality
feed holding tank equipped with a thermostated heat ex-
stainless steel (Type 316) or plastic for all wetted parts to
changer system to maintain the feed solution at the desired
prevent contamination of the feed solution by corrosion prod-
temperature, a booster pump, a high-pressure centrifugal
ucts. Do not use reactive piping material such as plain carbon
pump, and a reverse osmosis device. Use a valve with a
steel, galvanized or cadmium-plated carbon steel, and cast iron
for piping. Take care to ensure that no contamination will occur minimum flow restriction (for example, ball valve or plug
from oil films on new metal piping, release agents on raw valve) for the shut-off valve to prevent excessive pressure drop.
P—pressure tap locations
T—temperature measurement location
L—low-pressure shutoff probe location
H—high-pressure shutoff probe location
HT—high-temperature shutoff probe location
FIG. 1 Centrifugal High-Pressure Pump System Piping Diagram
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D 4194
P—pressure tap locations
T—temperature measurement location
L—low-pressure shutoff probe location
H—high-pressure shutoff probe location
HT—high-temperature shutoff probe location
FIG. 2 Positive Displacement High-Pressure Pump System Piping Diagram
The filter can be either a strainer (100-mesh) or a 5-μm filter reciprocating piston-type positive displacement pump is used
(based on supplier’s recommendation). Use a pressure control to feed the reverse osmosis device.
valve such as a ball valve for throttling the pump discharge. A 7.2.4 Operate the apparatus by drawing the feed solution
flow control valve is needed to regulate the concentrate flow. A from the tank and pumping it through the reverse osmosis
manual throttling valve, such as a needle valve, is sufficient for device under pressure. Return both the concentrate stream and
this application unless the flows are so low that plugging could the permeate to the feed tank so that its volume and solute
become a problem. In that case, use a long coil of high-pressure concentration remain constant. Use the heat exchanger coils in
media tubing to take the entire pressure drop through the the feed tank to adjust the feed to specified operating tempera-
tubing. Cut the tubing to length for the required flow. ture and thereafter use to remove the energy load generated by
7.2.3 See Fig. 2 for a schematic piping diagram for a the pump. Monitor the permeate temperature very near the
positive displacement high-pressure pump test system.Valves reverse osmosis device (within 500 mm). Pressure gages
and arrangements are similar to the centrifugal system except before and after the reverse osmosis device give the feed
for the high-pressure pump piping. The back-pressure regulator pressure and the pressure drop across the device (DP; feed
on the by-pass controls pressure on the pump discharge line. pressure − concentrate pressure). Locate these gages as close
Under no circumstances install throttling valves directly on a as possible to the reverse osmosis device. Measure the con-
positive displacement pump discharge line. An accumulator is centrate and permeate flow rates with calibrated flowmeters
required to minimize pressure pulsations (<1 % of value) if a from which the feed rate to the device may be determined.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 4194
Remove samples of these two streams through sampling valves containing in each litre 1.5 g of NaCl.
for conductivity/concentration measurements. Sample the feed 10.3 Sodium Chloride Feed Solution (0.5 g/L)—Dissolve
using the feed sample valve. Direct the return flows in the feed enough sodium chloride (NaCl) in water to make a solution
tank to provide adequate mixing. containing in each litre 0.5 g of NaCl.
7.3 Systems—To protect the reverse osmosis device and the 10.4 Sodium Chloride Feed Solutions, Optional—Other
high-pressure pump from abnormal operating conditions, in- concentrations of NaCl solutions (<10 g/L) can be used.
stall limit controls in the system. An electric limit control is
11. Procedure
used to shut down the high-pressure feed pump. The limit
11.1 Start-Up and Operating Procedure:
control circuit should have a manual reset relay in it so that
11.1.1 If the reverse osmosis device contains sanitizing or
when it shuts down it will not automatically restart. See Fig. 1
winterizing agents, or both, flush the device in accordance with
and Fig. 2 for the limit control locations. Their functions are as
the supplier’s recommendations.
follows:
11.1.2 Make preliminary checks to make sure all fittings are
7.3.1 High-Pressure Shut-Off—Set the cutoff point in accor-
tight, all components are operational, and the feed solution is at
dance with the supplier’s recommendations (protects the re-
the proper concentration and temperature. Before energizing
verse osmosis device against excessive pressure).
the high-pressure pump, the low-pressure switch must be off
7.3.2 Low-Pressure Shut-Off—Set the cutoff point at a gage
for start-up to complete the circuit past the low-pressure cutout.
pressure of 103 kPa (15 psi) (shuts the system down when the
Energize the high-pressure pump momentarily to check proper
pump water supply is interrupted and thus protects the reverse
rotation.
osmosis pump).
11.1.3 Open the feed supply valve, the concentrate flow
7.3.3 High-Temperature Shut-Off—Set the maximum tem-
control valve, the pump by-pass on the positive displacement
perature at 30°C (protects the reverse osmosis device against
feed pump, or the centrifugal pump throttling valve. Start the
excessive temperature).
booster pump and then the high-pressure pump.
7.4 Instrumentation :
11.1.4 Bring the feed pressure to a gage pressure of 2.75 6
7.4.1 Pressure—See Fig. 1 and Fig. 2 for pressure tap
0.07 MPa (400 6 10 psi). To reach 2.75 MPa, it is possible that
locations. Use a single gage equipped with a high-pressure“
the by-pass valve or the throttling valve (depending on pump
quick-connect” or Taylor plug gage fitting for measuring
system) and the concentrate flow control valve may need to be
individual pressures and device pressure drop (DP). Individual
adjusted simultaneously. If necessary, another pressure agreed
gages are also satisfactory but not as reliable as a“ quick-
upon between the user and the supplier may be used.
connect” test gage or a special DP gage. Use pressure snubbers
11.1.5 Set concentrate flow in accordance with the suppli-
to prevent pulsation damage to gages, and calibrate all pressure
er’s recommendation by adjusting the concentrate flow control
gages.
valve. But maintain conversion within 62 % of the supplier’s
7.4.2 Temperature—See Fig. 1 and Fig. 2 for temperature-
recommendation.
measurement locations. Calibrated dial thermometers with the
11.1.6 Recheck and adjust if necessary both the concentrate
probe immersed in the flowing water should provide good data.
flow and feed pressure to give the selected values for flow and
7.4.3 Permeate Back-Pressure Considerations—It is per-
pressure.
missible to operate reverse osmosis devices with a back-
11.1.7 Check and adjust the cooling system in the feed
pressure on the permeate. The maximum recommended back-
solution to give a permeate temperature of 25 6 1°C.
pressure for these methods is 35 kPa (5 psi). This pressure is
11.1.8 Once sustained operation is attained, energize the
more than adequate for transferring the permeate back to the
low-pressure shut-off switch.
feed tank.
11.2 Data Recording:
TEST METHOD A—BRACKISH WATER REVERSE
11.2.1 One hour after start-up, measure and record on a data
OSMOSIS DEVICES
sheet the inlet and outlet pressures of the filter and the feed,
concentrate, and permeate pressures.
8. Scope
11.2.2 At the same time measure and record the permeate
8.1 This test method covers the determination of the oper-
and concentrate flows using the calibrated flowmeters or a
ating characteristics of brackish water reverse osmosis devices
calibrated volume container and stopwatch.
using standard test conditions and can be used for all types of
11.2.3 Also at the same time measure and record the
devices (tubular, spiral wound, and hollow fiber).
permeate temperature and the conductivity of the feed, perme-
9. Summary of Test Method
ate, and concentrate, using a conductivity meter, or determine
the chloride content of the three streams in accordance with
9.1 The test method provides for at least three different
Test Methods D 512.
concentrations of sodium chloride feed solution.
11.2.4 Repeat the above measurements 2 to 3 h after start-up
10. Reagents and Materials
and hourly thereafter until three successive permeate flow rates
10.1 Sodium Chloride Feed Solution (5.0 g/L)—Dissolve (corrected to 25°C) and salt
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