ASTM D6157-97(2017)e1

Standard Practice for Determining the Performance of Oil/Water Separators Subjected to a Sudden Release

SIGNIFICANCE AND USE
5.1 The Clean Water Act promulgated the implementation of water quality standards and contamination limits for a wide range of pollutants including oil and grease. Specifically, the EPA, in 40 CFR Ch. 1, prohibits “the discharges of oil that cause a film or sheen upon or cause discoloration of the surface of the water. . .” Several state and local agencies have adopted this statement in addition to setting concentration limits, that is, 15 mg/L or even 5 mg/L. The purpose of this practice is to evaluate the performance of a separator in regards to the regulations and user requirements when subject to a sudden release. The sudden release may occur in dry weather and local personnel may attempt to hose the contaminated area down or it may occur on a rainy day and enter the separator mixed in with the runoff.  
5.2 This practice is not applicable if the influent to a separator is simply runoff from contaminated rainwater. For this case, see Practice D6104.  
5.3 This practice is not applicable if the influent to a separator is conveyed by a pumping means.
SCOPE
1.1 This practice describes the testing procedure, any necessary related apparatus, and the sampling technique to be used in determining the performance characteristics of an oil/water separator subjected to the sudden release of a relatively large quantity of hydrocarbons that may appear in its influent in pure form or at high concentration.  
1.2 This practice does not address the determination of the performance characteristics of an oil/water separator subjected to surface run-off resulting from rain water draining from improved or unimproved land. In this case, refer to Practice D6104.  
1.3 This practice does not address the determination of the performance characteristics of an oil/water separator subjected to a mechanically emulsified influent such as provided by a pump.  
1.4 This practice does not investigate the ability of the separator to handle debris or suspended solids, that is, grit or tree leaves.  
1.5 While the effluent may meet code requirements for total oil and grease content, this practice does not address the presence of soluble organics, that is, benzene, toluene, ethyl-benzene, and xylene (BTEXs) that may be detected in the effluent. It also does not make any provisions for the effects of detergents, surfactants, soaps or any water soluble matter (that is, salts) or any portion of an essentially insoluble matter that may be found in solution on separation. (Effects of certain water soluble chemicals or solids may be investigated by adding them to the water at predetermined constant concentrations.)  
1.6 In order to estimate the effect of water temperature on the performance of the separator, the tests described in this practice must be performed at two water temperatures. The selected temperatures must be at least 10°C (18°F) apart, with the temperature ranging from a minimum of 0°C (32°F) to a maximum of 50°C (122°F).  
1.7 This practice does not make any provisions for the variation of pH or temperature during a test run. Refer to Appendix X1 for further detail.  
1.8 This practice can be used with a variety of hydrocarbons. It adopts No. 2 fuel oil with a density2 of 845 kg/m3 (52.73 lbm/ft3) and a viscosity2 of 1.9 to 4.1 centistokes at 40°C (104°F) and SAE 90 lubricating oil with a density (See SAE J313) of 930 kg/m3 (58 lbm/ft3) at 15.5°C (60°F) and a viscosity (see SAE J306) of 13.5 to  
Note 1: No extrapolation outside the range of the tested influent or effluent oil concentrations is allowed as performance may not be linear. Hence, to establish performance at a higher or lower concentration, the separator shall be tested for that specific condition. In addition, linearity must be established prior to using linear interpolation.  
1.9 Since regulations are based on effluent total hydrocarbon content, this practice does not set forth any lower limits on oil particle size for the evaluation of ...

General Information

• Status: Published
• Publication Date: 14-Dec-2017
• ICS: 75.180.99 - Other equipment for petroleum and natural gas industries
• Technical Committee: D19 - Water
• Drafting Committee: D19.06 - Methods for Analysis for Organic Substances in Water

Relations

• Replaces: ASTM D6157-97(2011) - Standard Practice for Determining the Performance of Oil/Water Separators Subjected to a Sudden Release
• Effective Date: 15-Dec-2017
• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D6104-97(2017)e1 - Standard Practice for Determining the Performance of Oil/Water Separators Subjected to Surface Run-Off
• Effective Date: 15-Dec-2017
• Refers: ASTM D6104-97(2011) - Standard Practice for Determining the Performance of Oil/Water Separators Subjected to Surface Run-Off
• Effective Date: 01-May-2011
• Refers: ASTM D3370-10 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Dec-2010
• Refers: ASTM D1129-10 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2010
• Refers: ASTM D3370-08 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Oct-2008
• Refers: ASTM D3370-07 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Dec-2007
• Refers: ASTM D1129-06a - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06ae1 - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06 - Standard Terminology Relating to Water
• Effective Date: 15-Feb-2006
• Refers: ASTM D4281-95(2005)e1 - Standard Test Method for Oil and Grease (Fluorocarbon Extractable Substances) by Gravimetric Determination (Withdrawn 2012)
• Effective Date: 01-Dec-2005
• Refers: ASTM D1129-04 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-04e1 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-03a - Standard Terminology Relating to Water
• Effective Date: 10-Aug-2003

Overview

ASTM D6157-97(2017)e1, issued by ASTM International, is a standard practice for determining the performance of oil/water separators subjected to a sudden release of hydrocarbons. This standard addresses the need for reliable evaluation of separator systems in scenarios that mimic accidental spills or releases of oil, such as those regulated under the US Clean Water Act and EPA requirements (40 CFR Ch. 1). Designed in alignment with international standardization principles and recognized by the World Trade Organization (WTO) TBT Committee, this practice helps ensure consistent, reproducible testing that supports environmental compliance and public safety.

Key Topics

• Scope and Limitations

  • Applicable to oil/water separators experiencing a sudden, concentrated oil release, not steady contaminated runoff or mechanically emulsified influent.
  • Focuses solely on total hydrocarbon content in effluent-does not evaluate separator capabilities for debris, suspended solids, soluble organics (e.g., BTEX), detergents, surfactants, or pH/temperature variations during tests.
  • Requires testing at two different water temperatures (minimum 10°C apart, within 0°C to 50°C range).

• Test Procedure

  • Simulates sudden oil release by introducing a substantial quantity of hydrocarbon (such as No. 2 fuel oil or SAE 90 lubricating oil) to the separator influent.
  • Includes specific sampling requirements, apparatus, and recommended mixing techniques for accurate and repeatable results.
  • Effluent samples are analyzed for total oil and grease following EPA-approved methods.

• Performance Evaluation

  • Assesses separator’s capability to prevent oil from exceeding discharge limits, with results directly relevant to tested hydrocarbon types and concentrations.
  • Prohibits extrapolation beyond tested ranges unless validated by additional tests for linearity.

Applications

This standard has broad applicability in industries and municipal operations where oil/water separators are used to mitigate environmental impact of oil spills or accidental releases, such as:

• Industrial facilities: Testing compliance of separators installed at manufacturing plants, refineries, or maintenance areas where oil-handling equipment is present.
• Stormwater management: Evaluating separators that treat flows potentially subject to sudden oil contamination.
• Regulatory compliance: Ensuring that equipment meets EPA and local agency discharge regulations for oil, supporting Clean Water Act mandates.
• Product development and procurement: Providing standardized performance benchmarks for manufacturers and purchasers of oil/water separator systems.

Routine use of this standard supports environmental protection efforts by validating that separator systems can effectively manage unplanned hydrocarbon discharges and limit the risk of surface sheen or discoloration in surrounding waters.

Related Standards

• ASTM D6104 – For performance determination of oil/water separators subjected to surface runoff, rather than sudden releases.
• ASTM D1129, D3370 – Terminology and procedures related to water sampling and analysis.
• ASTM D4281, EPA Methods 413.1, 413.2, 1664 – Analytical methods referenced for oil and grease determination in water.
• SAE J306, SAE J313 – Standards referenced for hydrocarbon properties used in testing.

Summary

Following ASTM D6157-97(2017)e1 ensures consistent, reliable, and regulatory-compliant evaluation of oil/water separators’ performance in the event of a sudden oil release. This practice supports water quality objectives, helps meet environmental discharge limits, and delivers practical guidance for industries and regulators seeking to prevent oil pollution in natural water bodies.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
´1
Designation: D6157 − 97 (Reapproved 2017)
Standard Practice for
Determining the Performance of Oil/Water Separators
Subjected to a Sudden Release
This standard is issued under the fixed designation D6157; 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 (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—The Keywords Section was added editorially in December 2017.
1. Scope practice must be performed at two water temperatures. The
selected temperatures must be at least 10°C (18°F) apart, with
1.1 This practice describes the testing procedure, any nec-
the temperature ranging from a minimum of 0°C (32°F) to a
essaryrelatedapparatus,andthesamplingtechniquetobeused
maximum of 50°C (122°F).
in determining the performance characteristics of an oil/water
separator subjected to the sudden release of a relatively large 1.7 This practice does not make any provisions for the
quantity of hydrocarbons that may appear in its influent in pure variation of pH or temperature during a test run. Refer to
form or at high concentration. Appendix X1 for further detail.
1.2 This practice does not address the determination of the 1.8 This practice can be used with a variety of hydrocar-
performance characteristics of an oil/water separator subjected bons. It adopts No. 2 fuel oil with a density of 845 kg/
3 3 2
to surface run-off resulting from rain water draining from m (52.73 lb /ft ) and a viscosity of 1.9 to 4.1 centistokes at
m
improved or unimproved land. In this case, refer to Practice 40°C (104°F) and SAE 90 lubricating oil with a density (See
3 3
D6104. SAE J313) of 930 kg/m (58 lb /ft ) at 15.5°C (60°F) and a
m
viscosity (see SAE J306) of 13.5 to <24 centistokes at 100°C
1.3 This practice does not address the determination of the
(212°F) as the comparative testing media. It is understood that
performance characteristics of an oil/water separator subjected
the results obtained from this practice are only directly
to a mechanically emulsified influent such as provided by a
applicable to No. 2 fuel oil and SAE 90 lubricating oil for the
pump.
tested concentrations and only careful interpolation or
1.4 This practice does not investigate the ability of the
extrapolation, or both, is allowed to other hydrocarbons. Low
separator to handle debris or suspended solids, that is, grit or
viscosity or high density hydrocarbons or hydrocarbons that
tree leaves.
contain a larger fraction of highly soluble compounds may
need to be tested separately.
1.5 While the effluent may meet code requirements for total
oil and grease content, this practice does not address the
NOTE 1—No extrapolation outside the range of the tested influent or
presence of soluble organics, that is, benzene, toluene, ethyl-
effluent oil concentrations is allowed as performance may not be linear.
benzene, and xylene (BTEXs) that may be detected in the
Hence, to establish performance at a higher or lower concentration, the
separator shall be tested for that specific condition. In addition, linearity
effluent. It also does not make any provisions for the effects of
must be established prior to using linear interpolation.
detergents, surfactants, soaps or any water soluble matter (that
1.9 Since regulations are based on effluent total hydrocar-
is, salts) or any portion of an essentially insoluble matter that
may be found in solution on separation. (Effects of certain bon content, this practice does not set forth any lower limits on
oil particle size for the evaluation of separator efficiency.
water soluble chemicals or solids may be investigated by
adding them to the water at predetermined constant concentra- However, a standardized means for mixing oil and water shall
be specified to ensure repeatability. It must be noted however
tions.)
that smaller particles, having a greater surface area to volume
1.6 In order to estimate the effect of water temperature on
ratio, rise at a slower rate than their larger counterparts. (Guide
the performance of the separator, the tests described in this
F933 requires that 20 % of all oil particles be smaller than or
equal to 50 µm and IMO MEPC 60 (30) does not mention any
particle size requirements but asks the user to avoid emulsion
This practice is under the jurisdiction of ASTM Committee D19 on Water and
causing chemicals.)
is the direct responsibility of Subcommittee D19.06 on Methods for Analysis for
Organic Substances in Water.
Current edition approved Dec. 15, 2017. Published January 2018. Originally
approved in 1997. Last previous edition approved in 2011 as D6157 – 97 (2011). Bolz, R. E., andTuve, G. L., CRC Handbook of Tables forApplied Engineering
DOI: 10.1520/D6157-97R17E01. Science, 2nd Edition, CRC Press, 1991.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D6157 − 97 (2017)
1.10 Although the tests described in this practice intend to 2.3 SAE Standards:
simulate the performance of a separator subjected to a sudden SAE J306 Axle and Manual Transmission Lubricant Viscos-
ity Classification
release, they do not cover all possible applications. It is the end
SAE J313 Surface Vehicle Recommended Practice — (R)
user’s responsibility to determine whether his separation re-
Diesel Fuels
quirements are within the scope of this practice.
1.11 Aproduct different from the general description herein
3. Terminology
may be tested and found to be in compliance with the
3.1 Definitions:
performance criteria set forth.
3.1.1 For definitions of terms used in this standard, refer to
1.12 The values stated in SI units are to be regarded as Terminology D1129.
standard. The values given in parentheses are mathematical
3.2 Definitions of Terms Specific to This Standard:
conversions to inch-pound units that are provided for informa-
3.2.1 calibration, n—thecertifiedevaluationoftheaccuracy
tion only and are not considered standard.
of a measuring instrument as performed by its manufacturer or
an independent licensed or accredited third party.
1.13 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.2.2 contaminated run-off, n—rain water which has col-
responsibility of the user of this standard to establish appro-
lected oily contaminants from the surfaces it came in contact
priate safety, health, and environmental practices and deter- with and which may appear in the influent to a separator.
Unlikearelease,thelevelofcontaminationinthiscaseismuch
mine the applicability of regulatory limitations prior to use.
lower.
1.14 This international standard was developed in accor-
dance with internationally recognized principles on standard- 3.2.3 effluent, n—the aqueous release from a separator.
ization established in the Decision on Principles for the
3.2.4 flow totalizer, n—a counter, usually attached to a flow
Development of International Standards, Guides and Recom-
meter, that evaluates the total volume of the fluid that has
mendations issued by the World Trade Organization Technical
flowed through over a given time period.
Barriers to Trade (TBT) Committee.
3.2.5 influent, n—the oily aqueous input to a separator.
3.2.6 oily discharge, n—any release of oily contaminants
2. Referenced Documents
into the environment that exceeds the allowable limit.
2.1 ASTM Standards:
3.2.7 re-entrainment, n—the condition in which the level of
D1129 Terminology Relating to Water
contaminationoftheeffluentwaterofaseparatorcontainingoil
D3370 Practices for Sampling Water from Closed Conduits
is higher than the influent contamination level due to internal
D4281 Test Method for Oil and Grease (Fluorocarbon Ex-
remixing. This definition usually applies to situations where
tractable Substances) by Gravimetric Determination
clean water passes through a separator that already contains
(Withdrawn 2012)
Hydrocarbonsstoredwithinandatopthewatersoastoforman
D6104 Practice for Determining the Performance of Oil/
interface.
Water Separators Subjected to Surface Run-Off
3.2.8 release, n—any sudden discharge of an oily substance
F933 Guide for Evaluation of Oil Water Separation Systems
from vessels that are specifically designed to store, contain, or
for Spilled Oil Recovery Applications (Discontinued
transfer oily products such as storage tanks, pipelines, diked
2001) (Withdrawn 2001)
areas, and transfer equipment and which may appear in the
2.2 EPA Standards:
influent to a separator.
EPA-413.1 “Methods for Chemical Analysis of Water and
3.2.9 separator, n—a flow through primary treatment device
Wastes,” EPA 600/4-79-020
the primary purpose of which is to separate oil from water.
EPA-413.2 “Methods for Chemical Analysis of Water and
Wastes,” EPA 600/4-79-020 4. Summary of Practice
EPA-1664 H-Hexane Extractable Material (HEM) and Silica
4.1 The practice evaluates a separator’s ability to inhibit a
Gel Treated N-Hexane Extractable Material (SGT-HEM)
sudden release from escaping into its effluent. For this, a
by Extraction and Gravimetry (Oil and Grease and Total
quantity of hydrocarbon constituting at least the rated oil
Petroleum Hydrocarbons) EPA-821-B-94-004B
storage capacity of the separator is released at the separator’s
40 CFR Ch. 1 (7-1-95 Edition)
rated flow for the test conditions, either in pure form or mixed
with water to form a 500 000-mg/L concentration. It is then
immediately followed with fresh water. The corresponding
effluent hydrocarbon content is determined by obtaining and
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
analyzing grab samples.
Standards volume information, refer to the standard’s Document Summary page on
4.2 The data generated in this practice are considered valid
the ASTM website.
The last approved version of this historical standard is referenced on
for the separators tested only. However, the results of these
www.astm.org.
AvailablefromUnitedStatesEnvironmentalProtectionAgency(EPA),William
Jefferson Clinton Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460, Available from SAE International (SAE), 400 Commonwealth Dr.,Warrendale,
http://www.epa.gov. PA 15096, http://www.sae.org.
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D6157 − 97 (2017)
tests may be extrapolated to smaller or larger size separators the flow rate, that is, throttling valve and flow meter, orifice
provided that applicable geometric and dynamic similitude are plates, or venturis, to within 5 % of the desired value.
maintained. Where the use of extrapolation is not applicable,
NOTE 2—If the separator is to be fed by gravity, the oil storage tank
that size unit must be subjected to testing.
must be elevated above the water storage tank
...