ASTM F1693-21

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Designation: F1693 − 17 F1693 − 21
Standard Guide for
Consideration of Bioremediation as an Oil Spill Response
Method on Land
This standard is issued under the fixed designation F1693; 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.
1. Scope
1.1 The goal of this guide is to provide recommendations for the use of biodegradation enhancing agents for remediating oil spills
in terrestrial environments.
1.2 This is a general guide only, assuming the bioremediation agent to be safe, effective, available, and applied in accordance with
both manufacturers’ recommendations and relevant environmental regulations. As referred to in this guide, oil includes crude and
refined petroleum products.
1.3 This guide addresses the application of bioremediation agents alone or in conjunction with other technologies, following spills
on surface terrestrial environments.
1.4 This guide does not consider the ecological effects of bioremediation agents.
1.5 This guide applies to all terrestrial environments. Specifically, it addresses various technological applications used in these
environments.
1.6 In making bioremediation-use decisions, appropriate government authorities must be consulted as required by law.
1.7 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. In addition, it is the responsibility of the user to ensure that such activity takes place under the
control and direction of a qualified person with full knowledge of any potential or appropriate safety and health protocols.
1.8 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.
2. Terminology
2.1 Definitions:
2.1.1 aerobes—organisms that require air or free oxygen for growth.
2.1.2 anaerobes—organisms that grow in the absence of air or oxygen and do not use molecular oxygen in respiration.
This guide is under the jurisdiction of ASTM Committee F20 on Hazardous Substances and Oil Spill Response and is the direct responsibility of Subcommittee F20.13
on Treatment.
Current edition approved Aug. 1, 2017Feb. 1, 2021. Published January 2018February 2021. Originally approved in 1996. Last previous edition approved in 20132017 as
F1693 – 13.F1693 – 17. DOI: 10.1520/F1693-17.10.1520/F1693-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1693 − 21
2.1.3 bioaugmentation—the addition of microorganisms (usually predominantly bacteria) to increase the biodegradation rate of
target pollutants.
2.1.4 biodegradation—chemical alteration and breakdown of a substance, usually to smaller products, caused by microorganisms
or their enzymes.
2.1.5 bioremediation—enhancement of biodegradation.
2.1.6 bioremediation agents—inorganic and organic compounds and microorganisms that are added to enhance degradation
processes, predominantly microbial.
2.1.7 biostimulation—the addition of microbial nutrients, oxygen, heat, or water, or some combination thereof, to enhance the rate
of biodegradation of target pollutants by indigenous species (predominantly bacteria).
2.1.8 ecosystem—organisms and the surrounding environment combined in a community that is self-supporting.
3. Significance and Use
3.1 The purpose of this guide is to provide remediation managers and spill response teams with guidance on bioremediation.
3.2 Bioremediation is one of many available tools and may not be applicable to all situations. This guide can be used in
conjunction with other ASTM guides addressing oil spill response operations as well as options other than bioremediation.op-
erations.
4. General Considerations for Bioremediation Use
4.1 Bioremediation technologies attempt to accelerate the natural rate of biodegradation. In situ, solid-phase, and slurry-phase
represent the major bioremediation technologies used. These technologies may be unnecessary in those cases in which the natural
rate of biodegradation suffices, such as for thin films. The use of adequate controls in preliminary field studies, or the results of
previously reported studies, will assist in determining the extent to which microorganism or nutrient amendments, or both, are
necessary to obtain the desired rate of degradation.
4.2 Bioremediation performance depends on the efficiency of the petroleum hydrocarbon degrading indigenous microorganisms
or bioaugmentation agents. Performance also depends on the availability of rate-limiting nutrients and the susceptibility of the
target crude oil or refined product to microbial degradation. As oil consists of hundreds or more compounds, many of which require
different conditions or different microorganisms to degrade, oil biodegradation should not be considered a single process. Oil
biodegradation should at least consider the aliphatics separate from the aromatic compounds. Some compounds may degrade to
other compounds which may be toxic or less biodegradable. Other classes of compounds often degrade to a lesser degree, these
classes include resins, asphaltenes, large aliphatics and large aromatics (1, 2) .
4.2.1 In general, aerobic bioremediation systems degrade oil more rapidly than anaerobic systems, and adequate aeration may be
the most promising approach in many cases.
4.2.2 Numerous microorganisms, represented by hundreds of species, are responsible for the degradation of the oil. Various texts
describe the biodegradability and biodegradation rates of a variety of organic compounds present in oil (3, 4, 5).
4.2.3 The biodegradation of aliphatic and aromatic hydrocarbons in the absence of molecular oxygen is generally slower than
under aerobic conditions. Anaerobic biodegradation has been characterized under sulfate-reducing, nitrate-reducing and
methanogenic conditions (6, 7).
4.3 Bioremediation must be conducted under the guidance of qualified personnel who understand the safety and health aspects of
site activities.
The boldface numbers in parentheses refer to a list of references at the end of this standard.
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5. Background
5.1 Approaches to bioremediation for oil spill response include biostimulation, the addition of nutrients, oxygen, heat, or water,
or combination thereof, to stimulate indigenous microorganisms, and bioaugmentation, the addition of oil-degrading
microorganisms, which may be used in combination with biostimulation (8-17). As a precaution, it should be noted that nutrient
components may be toxic or harmful to plants, animals, and humans, and that non-indigenous species may alter the indigenous
microbial ecological balance at least temporarily. Indigenous microbes have been found to be more effective than non-indigenous
microbes (14, 18). Water effluent nitrate levels, which can affect drinking water sources, should be minimized to diminish risks
of health issues. Similarly, excessive ammonium levels should be avoided because they can affect fish and invertebrates, since
many are immobile and cannot avoid the treated area. Therefore, nitrogen and other nutrient levels should be monitored.
Instructions to ensure safety and effective product use should be established by the manufacturer or supplier for each commercial
microbial product, and specific instructions should be followed by the product user.
5.1.1 Biostimulation has been shown to enhance the biodegradation of terrestrial oil spills. Biostimulation uses the addition of
appropriate nutrients (for example, nitrogen, phosphorus, potassium, micronutrients, and so forth), oxygen, heat, or water, which
may have been limiting factors. If microbial degraders of the target oil contaminants are present in the soil or contaminated waters,
these approaches usually lead to increases in the rate of degradation. In some cases, there may not be a sufficient indigenous
oil-degrading population to stimulate. This may be the case in environments in which the degrader population has not developed.
Alternately, the toxic nature of the petroleum product may diminish or eliminate microorganisms. Also, the excavation of soil from
anoxic zones and subsequent relocation to an oxygen-rich environment may result in a lack of microbial degraders due to the
drastic change in conditions. The microbial response to biostimulation may include a lag period (weeks to months) for the growth
or natural selection of degraders to occur. Microorganisms, as well as oil contaminants, should be monitored throughout the process
to establish efficacy and safety.
5.1.2 Bioaugmentation may use commercial microbial products, on-site production of microbes from stock cultures, or laboratory
isolation, characterization, and subsequent production of microbes from the particular site (or another site similar in soil and
contaminant characteristics). This approach may increase soil microbe concentrations rapidly. Microbes selected must be
nonpathogenic and must metabolize the oil contaminant(s), reducing toxicity. Growth requirements of the microbes need to be well
understood. Their growth rate is controlled by the limiting growth conditions of temperature, pH, nutrients, water, oxygen, the
contaminated medium (soil, sludge, and water), and oil. Microorganisms as well as oil components should be monitored to
establish efficacy and safety. Addition of non-indigenous microbes has not been found to be highly effective (14, 18).
5.1.3 While apparently safe and effective in the laboratory setting, genetically engineered oil-degrading microorganisms have only
rarely been authorized for environmental release (for example,19).
5.2 There are several bioremediation technologies available. It is important to understand the potential use of these systems when
assessing their applicability for full-scale implementation. Costs are determined by the size of the site, soil properties, type and
level of oil contaminant(s), goals, time allowed for attaining the goals, and testing requirements.
5.3 In situ bioremediation occurs without excavation of the contaminated soil. This technology relies predominantly on the
enhanced degradation of oil by bacteria following the addition of nutrients, air, oxygen or oxygen-releasing compounds, and
moisture. This has usually been demonstrated through the use of indigenous microorganisms. Ground-water treatment may be
achieved simultaneously or through pump and ex situ treatment methods. Anaerobic biodegradation systems can also be promoted;
however, their utility has been limited to date. Since soil is not excavated, volatile release is limited, and the risks and costs
associated with excavation and treatment are reduced.
5.3.1 Bioventing involves the introduction of air under pressure to the unsaturated zone of contaminated soil. The process pulls
or pushes air into the soil for use by the aerobic microorganisms. Although the purpose is to deliver oxygen required by the
microbes, it may dry the soil and require the addition of moisture. Furthermore, the flow of air will desorb some of the more volatile
components from the soil (for example, gasoline-contaminated soil), and the exhaust gases may have to be treated. Successful
treatment requires adequate soil porosity, moisture, nutrients, and microorganisms with the appropriate biodegradation abilities.
Additives may be provided at or near the surface to percolate through the treatment zone.
5.3.2 Biosparging is similar to bioventing except that air is injected directly into the ground below the water table in the saturated
zones, and contaminant volatility (and subsequent treatment) is encouraged. Although the purpose is to deliver oxygen required
by the microbes, vacuum pumps are often used to recover vapors for treatment prior to discharge. Nutrients and microbes may be
added in the injection well to stimulate and augment biodegradation.
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5.4 Solid-phase bioremediation treats soils above ground, primarily in contained treatment cells or tanks. Techniques similar to
landfarming are used, including irrigation, tilling, and nutrient and microbe additions. As with in situ bioremediation, treatment
can involve biostimulation or bioaugmentation. Losses through volatilization and leaching can be minimized through treatment
design and implementation. The contaminated soil is contained, and is defined with respect to the volume and concentration of the
oil, especially as the soil is homogenized during processing.
6. Methodologies
6.1 A comprehensive contaminated materials handling plan (CMHP) should be developed prior to excavation and treatment. It
may include the designation of a materials staging area present within the treatment facility and equipment decontamination within
delineated exclusion zones.
6.2 A comprehensive health and safety program should be in effect throughout the remediation project. This program may include
medical examinations of employees, contact and respiratory protection, and air, soil, and water monitoring.
6.3 The treatment facility should contain appropriate protection from rainfall and flooding
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