EPA/600/R-04/075 

July 2004 

LITERATURE REVIEW ON THE USE OF 

COMMERCIAL BIOREMEDIATION AGENTS 

FOR CLEANUP OF OIL-CONTAMINATED 

ESTUARINE ENVIRONMENTS 

by 

1

Xueqing Zhu, 2Albert D. Venosa, and 1Makram T. Suidan, 

1

University of Cincinnati 

Cincinnati, OH 45221 

2

U.S. Environmental Protection Agency 

National Risk Management Research Laboratory 

Cincinnati, OH 45268 

EPA Contract No. 68-C-00-159 

Task Order No. 19 

Task Order Manager 

Albert D. Venosa 

Land Remediation and Pollution Control Division 

National Risk Management Research Laboratory 

Cincinnati, OH 45268 

National Risk Management Research Laboratory 

Office of Research and Development 

U.S. Environmental Protection Agency 

Cincinnati, OH 45268
ii 

Disclaimer 

The information in this document has been funded by the United States Environmental 

Protection Agency (U.S. EPA) under Task Order No. 19 of Contract No. 68-C-00-159 to the 

University of Cincinnati. It has been subjected to the Agency’s peer and administrative reviews 

and has been approved for publication as an EPA document. Mention of trade names or 

commercial products does not constitute an endorsement or recommendation for use. 
iii 

Foreword 

The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the 

Nation’s land, air, and water resources. Under a mandate of national environmental laws, the 

Agency strives to formulate and implement actions leading to a compatible balance between 

human activities and the ability of natural systems to support and nurture life. To meet this 

mandate, EPA’s research program is providing data and technical support for solving 

environmental problems today and building a science knowledge base necessary to manage our 

ecological resources wisely, understand how pollutants affect our health, and prevent or reduce 

environmental risks in the future. 

The National Risk Management Research Laboratory (NRMRL) is the Agency’s center for 

investigation of technological and management approaches for preventing and reducing risks 

from pollution that threaten human health and the environment. The focus of the Laboratory’s 

research program is on methods and their cost-effectiveness for prevention and control of 

pollution to air, land, water, and subsurface resources; protection of water quality in public water 

systems; remediation of contaminated sites, sediments and ground water; prevention and control 

of indoor air pollution; and restoration of ecosystems. NRMRL collaborates with both public 

and private sector partners to foster technologies that reduce the cost of compliance and to 

anticipate emerging problems. NRMRL’s research provides solutions to environmental problems 

by: developing and promoting technologies that protect and improve the environment; advancing 

scientific and engineering information to support regulatory and policy decisions; and providing 

the technical support and information transfer to ensure implementation of environmental 

regulations and strategies at the national, state, and community levels. 

This publication has been produced as part of the Laboratory’s strategic long-term research plan. 

It is published and made available by EPA’s Office of Research and Development to assist the 

user community and to link researchers with their clients. 

 Lawrence W. Reiter, Acting Director 

 National Risk Management Research Laboratory 
iv 

Executive Summary 

The objective of this document is to conduct a comprehensive review of the use of commercial 

bioremediation products treating oil spills in all environments. Literature assessed includes peerreviewed articles, company reports, government reports, and reports by cleanup contractors 

engaged in responses to oil spills. The scope of this review is in the general context of estuarine 

environments. However, marine shorelines, terrestrial environments, freshwaters, and wetlands 

are frequent candidates for bioremediation of spilled oil, and these ecosystems are also included 

in the review for completeness. The review will be useful for oil spill responders (e.g., on-scene 

coordinators and response contractors) to better understand the feasibility of bioremediation 

technology and as an aid in selecting bioremediation products. 

This state-of-science review on the efficacy of bioremediation products is conducted using 

different approaches and presented accordingly as follows. Section 1 provides an overall 

introduction of the background and the scope of this review. Section 2 presents an in-depth 

review of field tests of bioremediation products based on the scientific literature, which includes 

peer-reviewed journal articles, books, and major conference proceedings. Section 3 evaluates oil 

bioremediation products based on the non-peer reviewed literature articles gathered, such as 

government agency reports and vendor/service provider reports. Finally, Section 4 gives the 

conclusions and recommendations based on the reviewed information. 

The overall conclusions reached by this review are as follows. First, according to the peerreviewed literature, bioaugmentation appears to have little benefit for the treatment of spilled oil 

in an open environment. Microbial addition has not been shown to work better than nutrient 

addition alone in many field trials. However, case studies provided by vendors seem to suggest 

that application of bioaugmentation products could still have some potential in the treatment of 

specific oil components, isolated spills in confined areas, or certain environments where oildegrading microorganisms are deficient. Unfortunately, the evidence for such a conclusion is not 

strong and in most, if not all, cases is scientifically deficient. 

Biostimulation has been proven to be a promising tool to treat certain aerobic oil-contaminated 

shorelines. One of the key factors for the success of oil biostimulation is to maintain an optimal 

nutrient level in the interstitial pore water. In general, commercial oleophilic nutrient products 

have not shown clear advantages over common agricultural fertilizers in stimulating oil 

biodegradation. Effects of nutrients are also highly site-specific. For example, the availability of 

oxygen rather than nutrients is often the limiting factor in wetland environments, where addition 

of nutrient products has not been successful in enhancing oil biodegradation. 

The extreme uncertainty associated with the efficacy of bioremediation agents is due in large part 

to the poorly designed field tests that have been conducted to demonstrate efficacy. Much of the 

reported literature either lacked proper controls and quality assurance, or the data were 

incorrectly analyzed. If there is any hope for advancement of commercial bioremediation, 

experiments based on sound scientific principles are needed. Unfortunately, due to the extreme 

resource intensiveness of field studies, the benefit accruing to testing one bioremediation agent is 

only applicable to the one product being tested. Testing products in the field is not within the 

purview of the federal government unless such a test has the potential of advancing science in 

terms of general microbiological and engineering principles. 
v 

TABLE OF CONTENTS 

Executive Summary....................................................................................................................... iv 

1 Introduction and Background ................................................................................................. 1 

1.1 Objectives and Scope...................................................................................................... 2 

1.2 Organization of the Document........................................................................................ 3 

2 Assessment of Bioremediation Products in the Field: Peer-Reviewed Literature.................. 4 

2.1 Bioremediation Products and Evaluation ....................................................................... 4 

2.1.1 Bioremediation agents ............................................................................................ 4 

2.1.2 Assessing oil bioremediation in the field................................................................ 7 

2.2 Application of Bioaugmentation Products...................................................................... 8 

2.3 Application of Biostimulation Products........................................................................ 11 

2.3.1 Common agricultural fertilizers............................................................................ 12 

2.3.1.1 Water-soluble fertilizers.................................................................................... 12 

2.3.1.2 Slow-release fertilizers...................................................................................... 14 

2.3.2 Commercial biostimulation agents ....................................................................... 17 

2.3.2.1 Inipol EAP22 .................................................................................................... 17 

2.3.2.2 BIOREN............................................................................................................ 18 

2.3.2.3 Oil Spill Eater II® (OSE II)............................................................................... 19 

2.4 Summary....................................................................................................................... 20 

3 Assessment of Oil Bioremediation Products: Non-Peer Reviewed Literature ..................... 22 

3.1 Government Agency Reports........................................................................................ 22 

3.1.1 Application of bioaugmentation products............................................................. 22 

3.1.2 Application of biostimulation products ................................................................ 24 

3.2 Vendor’s Reports .......................................................................................................... 25 

3.2.1 Information collection........................................................................................... 26 

3.2.2 Summary of case studies submitted by vendors ................................................... 28 

3.2.2.1 Enviro-Zyme, Inc.............................................................................................. 28 

3.2.2.2 Forrester Environmental Technologies Corp. (FET Group)............................. 29 

3.2.2.3 Garner Environmental Services, Inc..................................................................... 29 

3.2.2.4 Industrial Wastewater Solutions Corp. ............................................................. 30 

3.2.2.5 Medina Agriculture Products Co., Inc. ................................................................. 31 

3.2.2.6 Petrol Rem, Inc. .................................................................................................. 33 

3.2.2.7 Verde Environmental, Inc................................................................................... 34 

3.2.2.8 WMI International, Inc. ...................................................................................... 35 

3.2.3 Review of vendor reports...................................................................................... 40 

3.3 Bioremedial Approaches for Controlling Petroleum Hydrocarbons in Stormwater and 

Bilge Water. .............................................................................................................................. 42 

3.3.1 Bioremediation of hydrocarbon contamination from storm water discharges............. 42 

3.3.2 Bioremedial approaches for treating bilge oil....................................................... 43 

4 Summary and Findings ......................................................................................................... 44 

5 References............................................................................................................................. 46 
1 Introduction and Background 

It is estimated that between 1.7 and 8.8 million metric tons of oil are released into the 

world’s water every year (NAS, 1985), of which more than 90% is directly related to human 

activities including deliberate waste disposal. Marine oil spills, particularly large-scale spill 

accidents, have received great attention due to their catastrophic damage to the environment. For 

example, the spill of 37,000 metric tons (11 million gallons) of North Slope crude oil into Prince 

William Sound, Alaska, from the Exxon Valdez in 1989 led to the mortality of thousands of 

seabirds and marine mammals, a significant reduction in population of many intertidal and 

subtidal organisms, and many long term environmental impacts (Spies et al., 1996). Minor oil 

spills and oil contamination from non-point source discharges (e.g., urban runoff and boat bilge) 

are no less threats to public health and the environment, although they have received much less 

attention in the past. According to recent National Water Quality Inventory reports, non-point 

source pollution remains the Nation’s largest source of water quality problems (U.S. EPA, 

1996&2000). It is the main reason that approximately 40 % of surveyed rivers, lakes, and 

estuaries are not clean enough to meet basic uses such as fishing or swimming. 

Conventional oil spill countermeasures include various physical, chemical, and biological 

methods. Commonly used physical methods include booming and skimming, manual removal 

(wiping), mechanical removal, water flushing, sediment relocation, and tilling. Physical 

containment and recovery of bulk or free oil is the primary response option of choice in the 

United States for the cleanup of oil spills in marine and freshwater shoreline environments. 

Chemical methods, particularly dispersants, have been routinely used in many countries as a 

response option. However, chemical methods have not been extensively used in the United 

States due to the disagreement about their effectiveness and the concerns of their toxicity and 

long-term environmental effects (U.S. EPA, 1999). With the recent development of less toxic 

chemical dispersants, the potential for their applications may increase. 

Although conventional methods, such as physical removal, often are the first response 

option, they rarely achieve complete cleanup of oil spills. According to the Office of 

Technology Assessment (OTA, 1990), current mechanical methods typically recover no more 

than 10-15 percent of the oil after a major spill, although significantly higher recoveries have 

been achieved, depending on the environment. Bioremediation is beginning to emerge as a 

promising technology, particularly as a secondary treatment option for oil cleanup. 

Bioremediation has been defined as “the act of adding materials to contaminated environments to 

cause an acceleration of the natural biodegradation processes” (OTA, 1991). This technology is 

based on the premise that a large percentage of oil components are readily biodegradable in 

nature (Atlas, 1984, 1981; Prince, 1993). Bioremediation has several potential advantages over 

conventional technologies, such as being less costly, less intrusive to the contaminated site, and 

more environmentally benign in terms of its end products. 

The success of oil spill bioremediation depends on one’s ability to establish and maintain 

conditions that favor enhanced oil biodegradation rates in the contaminated environment. 

Numerous scientific review articles have covered various factors that influence the rate of oil 

biodegradation (Zobell 1946; Atlas, 1981 & 1984; Atlas and Bartha, 1992; NAS, 1985; Focht 

and Westlake, 1987; Leahy and Colwell, 1990). One important requirement is the presence of 

microorganisms with the appropriate metabolic capabilities. If these microorganisms are 
2 

present, then optimal rates of growth and hydrocarbon biodegradation can be sustained by 

ensuring that adequate concentrations of nutrients and oxygen are present and that the pH is 

between 6 and 9. The physical and chemical characteristics of the oil and oil surface area are 

also important determinants of bioremediation success. There are two main approaches to oil 

spill bioremediation: 

• Bioaugmentation, in which known oil-degrading bacteria are added to supplement the 

existing microbial population, and 

• Biostimulation, in which the growth of indigenous oil degraders is stimulated by the 

addition of nutrients or other growth-limiting co-substrates. 

Although extensive research has been conducted on oil bioremediation during the last 

decade, the effectiveness of this technology has only rarely been convincingly demonstrated, and 

in the case of commercial bioremediation products, the literature is virtually completely lacking 

in supportive evidence of success. Most existing studies have concentrated on evaluating the 

factors affecting oil bioremediation or testing favored products and methods through laboratory 

studies (Mearns, 1997). Only limited numbers of pilot-scale and field trials, which may provide 

the most convincing demonstrations of this technology, have been reported in the peer-reviewed 

literature (Prince 1993, Swannell et al, 1996, Venosa et al., 1996 and 2002). The scope of current 

understanding of oil bioremediation is also limited because the emphasis of most of these field 

studies and reviews has been on the evaluation of bioremediation technology for dealing with 

large-scale oil spills on marine shorelines. To help oil spill responders in the selection and 

application of bioremediation products, there is an immediate need to gather and evaluate 

information about the field performance of commercial bioremediation products, especially for 

dealing with low-level petroleum hydrocarbon contamination. 

To better understand the potential effectiveness of bioremediation technology, Public 

Law 105-457 entitled “Estuaries and Clean Waters Act of 2000” (the Act) was enacted, which 

states specifically that “the Administrator of the Environmental Protection Agency (EPA) shall 

begin a two-year study on the efficacy of bioremediation products.” The Act mandated that “the 

study shall evaluate and assess bioremediation technology (a) on low-level petroleum 

hydrocarbon contamination from recreational boat bilges, (b) on low-level petroleum 

hydrocarbon contamination from storm water discharges, (c) on non-point source petroleum 

hydrocarbon discharges, and (d) as a first response tool for petroleum hydrocarbon spills.” This 

report is a part of EPA’s efforts to address the Congressional mandate under the Act by extensive 

review of literature where bioremediation products have been used for oil spill cleanup. 

1.1 Objectives and Scope 

The objective of this document is to conduct a thorough assessment of bioremediation 

products by a comprehensive review of the actual use of bioremediation in real world cases. 

Literature assessed includes peer-reviewed articles, company reports, government reports, and 

actual reports by cleanup contractors engaged in responses to spills in inland, estuarine, and 

marine environments. The review will be useful for oil spill responders (e.g., on-scene 

coordinators and response contractors) to better understand the feasibility of bioremediation 

technology and as an aid in selecting bioremediation products. 
3 

As mentioned earlier, only a limited number of scientific, peer-reviewed journal articles 

are available on the performance of bioremediation products for oil spill cleanups. However, 

there are many reports pertaining to the use of bioremediation products in the non-peer reviewed 

or “gray” literature. Various government agencies [e.g., U.S. EPA, U.S. Coast Guard, U.S. Navy, 

U.S. Army, Department of Energy (DOE), the National Oceanic and Atmospheric 

Administration (NOAA)] have involved field investigation of bioremedial approaches for 

treating petroleum hydrocarbon contamination. More than 170 companies around the world are 

listed in Oil Spill Intelligence Report (2000), which offer either bioremediation products or 

bioremediation services. It is reasonable to assume that many field trials or applications 

conducted by government agencies, vendors, and responders have been documented but are not 

readily available to the public for various reasons. A thorough search for the “gray” literature is 

an important part of this project. The in-depth review of these non-peer reviewed reports will fill 

the “information gap” and provide a better picture in regard to the present and potential of the 

use of bioremediation products as a viable option for oil spill cleanups. 

It should be noted that all the reports collected are evaluated comprehensively for their 

scientific merit, and only those judged appropriate and scientifically sound are earmarked for 

inclusion in this document. If a report is deemed invalid due to technical deficiencies or 

insufficient information, it will also be mentioned but explanations given to why it was not an 

integral part of our final recommendation. 

The scope of this review is in the general context of estuarine environments. However, 

marine shorelines, terrestrial environments, freshwaters, and wetlands are frequent candidates for 

bioremediation of spilled oil, and these ecosystems are also included in the review for 

completeness. 

1.2 Organization of the Document 

This state-of-science review on the efficacy of bioremediation products is conducted 

using three different approaches and, accordingly, presented in the following major Sections. 

Section 2 presents an in-depth review of field tests of bioremediation products based on scientific 

literature, which includes peer-reviewed journal articles, books, and major conference 

proceedings (e.g., International Oil Spill Conference and International Bioremediation 

Symposium). Section 3 evaluates oil bioremediation products based on all the non-peer reviewed 

literature articles gathered, such as government agency reports and vendor/service provider 

reports. A discussion is also presented in Section 3 in regard to the potential of using 

bioremediation products in the areas of non-point source and stormwater runoff countermeasures 

and for treating bilge oil from boats, ships, cutters, and other watercraft. Finally, Chapter 4 gives 

the conclusions and recommendations based on all the information reviewed throughout this 

document. 
4 

2 Assessment of Bioremediation Products in the Field: Peer-Reviewed Literature 

Field studies can provide the most convincing demonstration of the effectiveness of oil 

bioremediation since laboratory studies are not always able to account for numerous real world 

conditions such as spatial heterogeneity, biological interactions, and mass transfer limitations. 

Swannell et al. (1996) conducted the most extensive review available on field evaluations of oil 

bioremediation in marine environments. Venosa (1998) presented an in-depth critical review of 

research studies emphasizing extensive inadequacies in the experimental design and control of 

published field tests. Other reviews are also available (Prince, 1993; Leahy and Colwell, 1990). 

However, none of existing reviews has focused on the field performance of commercial 

bioremediation agents. They did not distinguish bioremediation due to addition of commercial 

products and bioremediation due to application of common agricultural fertilizers/nutrient 

solutions or non-commercial microbial strains. This chapter will present a comprehensive review 

with the emphasis on the efficacy of commercial bioremediation products in the field by 

reviewing latest peer reviewed articles, as well as summarizing major points identified in the 

previous reviews. Non-commercial products or common agricultural fertilizers may also be 

covered only for the purpose of comparison. 

2.1 Bioremediation Products and Evaluation 

2.1.1 Bioremediation agents 

The U.S. EPA has defined Bioremediation agents as “microbiological cultures, enzyme 

additives, or nutrient additives that significantly increase the rate of biodegradation to mitigate 

the effects of the discharge” (Nichols, 2001). Bioremediation agents are also classified as 

bioaugmentation agents and biostimulation agents based on the two main approaches to oil spill 

bioremediation. Numerous bioremediation products have been proposed and promoted by their 

vendors, especially during early 1990s, when bioremediation was popularized as “the ultimate 

solution” to oil spills (Hoff, 1993). The U.S. EPA is often inundated with salespeople wanting to 

have EPA endorse their products. To have bioremediation products used properly, the U.S. EPA 

has compiled a list of bioremediation agents (Nichols, 2001; USEPA, 2002) as part of the 

National Oil and Hazardous Substances Pollution Contingency Plan (NCP) Product Schedule, 

which is required by the Clean Water Act, the Oil Pollution Act of 1990, and the National 

Contingency Plan. The Schedule is intended for use by Federal On-Screen Coordinators 

(FOSCs), Regional Response Teams (RRT), and other oil spill responders as an aid in 

determining the most appropriate products to use in various spill scenarios. 

At the time of this writing, 15 bioremediation agents were listed on the NCP Schedule as 

shown in Table 2.1. This list has been modified recently, and the number has been reduced to 

nine. A product can be placed on the Schedule only if all the required data have been submitted 

and when its safety and effectiveness have been demonstrated under the conditions of a test 

protocol developed by EPA (NETAC, 1993a; Nichols, 2001). However, the listing of a product 

on the Schedule does not mean that the product is approved or certified for use on an oil spill. At 

present, the only efficacy requirement for being listed is to pass the Bioremediation 28-Day 

Effectiveness Test. The test protocol uses laboratory shake flasks to compare the degradation of 

artificially-weathered crude oil in natural seawater with and without a bioremediation product. 

This test alone cannot demonstrate that a product will be effective in the field. Studies have 
5 

shown that bioremediation products may be effective in the laboratory but significantly less so in 

the field (Lee et al., 1997, Mearns, 1997; Venosa et al., 1992 and 1996). This is because 

laboratory studies cannot always simulate complicated real world conditions such as spatial 

heterogeneity, biological interactions, climatic effects, and nutrient mass transport limitations. 

Therefore, field studies and applications are the ultimate tests or the most convincing 

demonstration of the effectiveness of bioremediation products. 
6 

Table 2.1 Bioremediation agents in NCP product schedule (Adapted from USEPA, 2002) 

Name or Trademark Product Type Manufacture 

BET BIOPETRO MC BioEnviro Tech, Tomball, TX 

BILGEPRO NA International Environmental Products, LLC, 

Conshohocken, PA 

INIPOL EAP 22 NA Societe, CECA S.A., France 

LAND AND SEA NA Land and Sea Restoration LLC, San Antonio, 

RESTORATION TX 

MICRO-BLAZE MC Verde Environmental, Inc., Houston, TX 

OIL SPILL EATER II NA/EA Oil Spill Eater International, Corporation 

Dallas, TX 

OPPENHEIMER FORMULA MC Oppenheimer Biotechnology, Inc., Austin, TX 

PRISTINE SEA II MC Marine Systems, Baton Rouge, LA 

STEP ONE MC B & S Research, Inc., Embarrass, MN 

SYSTEM E.T. 20 MC Quantum Environmental Technologies, Inc. 

(QET), La Jolla, CA 

VB591TMWATER, 

VB997TMSOIL, AND 

NA BioNutraTech, Inc., Houston, TX 

BINUTRIX 

WMI-2000 MC WMI International, Inc., Houston, TX 

Abbreviations of product type: 

MC -- Microbial Culture 

EA -- Enzyme Additive 

NA -- Nutrient Additive 
7 

2.1.2 Assessing oil bioremediation in the field

Compared to laboratory investigations, few tests have been carried out to evaluate the 

effectiveness of bioremediation products in the field because such trials are both difficult and 

expensive to conduct. One of the most difficult tasks in field studies is the proper evaluation of 

oil biodegradation. Oil contaminated sites are often highly heterogeneous, where oil 

concentrations can vary greatly within a small area. Physical and chemical weathering may also 

significantly affect the composition and concentration of oil contamination. Consequently, 

variability associated with field studies can be so high as to preclude or interfere with one’s 

ability to discern significant treatment differences. Nevertheless, the efficacy of bioremediation 

in the field can be verified through well-designed monitoring programs and proper data 

interpretation. 

Evidence for the effectiveness of oil bioremediation should include: (1) faster 

disappearance of oil in treated areas than in untreated areas, and (2) a demonstration that 

biodegradation was the main reason for the increased rate of oil disappearance. To obtain such 

evidence, one has to be careful in selecting proper oil analysis procedures as well as in 

interpreting the data. Oil analysis methods can be generally classified into two categories: 

nonspecific methods to measure total petroleum hydrocarbons (TPHs), and specific methods 

using various chromatographic techniques to quantify target oil constituents. Total petroleum 

hydrocarbons (TPH) techniques have been widely accepted methods to rapidly quantify the oil 

due to their simplicity and low costs. However, these methods are severely affected by the spatial 

heterogeneity and, more importantly, they are much less able to distinguish between abiotic and 

biotic losses. The reason for this is that conventional TPH analysis is confounded by the presence 

of plant lipids and other biogenic compounds that interfere with interpretation of the analysis. 

In recent years, non-biodegradable or slowly biodegradable components in oil - often 

called biomarkers - have been used successfully to distinguish between biodegradation and the 

physical or chemical loss of oil and to mitigate the high variability associated with field studies 

(Bragg et al., 1994; Venosa et al., 1996; Lee et al., 1997). This approach estimates the extent of 

biodegradation by using GC/MS techniques and evaluating the ratios of target hydrocarbon 

concentrations relative to the concentration of these recalcitrant biomarkers, such as hopanes and 

steranes and to a lesser extent alkyl-substituted 4-ring PAHs such as C3-chrysene. Studies have 

shown that normalizing target oil constituents to biomarkers mitigates the spatial variability of 

oil contamination when compared to other mass balance approaches and allows biodegradation 

to be monitored effectively by reducing the number of samples required (Douglas et al., 1994). 

To ensure that monitored results reflect reality in a highly heterogeneous environment, it 

is also critical that a bioremediation sampling plan be designed according to valid statistical 

principles that include the principles of randomization, replication, and the use of proper 

controls. For example, to minimize bias, a random sampling plan should be used to evaluate 

treatment effects and their variance within the bioremediation zone. Efforts should also be made 

to ensure that an adequate number of independent samples are taken to reach a given accuracy 

and confidence. A proper control or untreated set aside area is also critical to demonstrate the 

true impact of a treatment. Detailed procedures to properly evaluate oil bioremediation can be 

found in Guidelines for the Bioremediation of Marine Shorelines and Freshwater Wetlands (Zhu 
8 

et al., 2001). All these principles will be used as the basis to evaluate the technical merit of the 

literature reviewed in this document. 

2.2 Application of Bioaugmentation Products 

Since the 1970s, bioaugmentation, or the addition of oil-degrading microorganisms to 

supplement the indigenous populations, has been proposed as an alternate strategy for the 

bioremediation of oil contaminated environments. The rationale for this approach is that 

indigenous microbial populations may not be capable of degrading the wide range of potential 

substrates present in complex mixtures such as petroleum (Leahy and Colwell, 1990) or that they 

may be in a stressed state as a result of the recent exposure to the spill. Other conditions under 

which bioaugmentation may be considered are when the indigenous hydrocarbon-degrading 

population is low, the speed of decontamination is the primary factor, and when seeding may 

reduce the lag period to start the bioremediation process (Forsyth et al., 1995). For this approach 

to be successful in the field, the seed microorganisms must be able to degrade most petroleum 

components, maintain genetic stability and viability during storage, survive in foreign and hostile 

environments, effectively compete with indigenous microorganisms, and move through the pores 

of the sediment to the contaminants (Atlas, 1977; Goldstein et al., 1985). 

Methods involving the addition of selected oil-degrading microorganisms into spilled oil 

have been patented and marketed since early 1970s (Azarowick, 1973; Linn, 1971; and Mohan et 

al., 1975). However, before the Exxon Valdez spill in 1989, little information on the performance 

of commercial bioaugmentation products was available in the peer-reviewed literature. Atlas and 

Bartha (1973) conducted one of the first laboratory tests on the effectiveness of commercial 

mixed bacterial cultures. Two commercial petroleum-degrading bacterial inocula, Ekolo-Gest 

(also marketed as Petrobac, National Chem. Corp.) and DBC bacteria (Gerald Bauer Corp.), 

were tested using shake flasks to compare the degradation of Sweden crude oil. The study found 

that none of the commercial mixtures was superior to the indigenous microorganisms in coastal 

marine waters. 

One of first field trials on oil bioremediation using a microbial product in a marine 

environment was reported by Lee and Levy (1987). The study involved seeding a mixed culture 

of marine oil-degrading bacteria (strains of Pseudomonas aeruginosa, Pseudomonas stutzeri, and 

Bacillus subtilis grown on bran) in a Scotian Shelf Condensate (SSC) contaminated sandy beach. 

The extent of biodegradation was measured by the decline in the n-C17/pristane ratio in this 

study. The results showed that the n-C17/pristane ratio in the seeded plots did decrease slightly. 

However, due to high inter-and intra-plot variability, no significant difference in the rate of oil 

loss was observed among the treatments. This study also observed that the number of oildegrading bacteria did not increase until 10 to 15 days after the addition of oil. However, the 

addition of the microbial product did not reduce this lag period, suggesting that the toxic volatile 

components in the oil, which evaporated mostly during the first week, was the main cause of the 

lag period. 

Since the application of nutrient amendments for the cleanup of the Exxon Valdez spill in 

1989, bioremediation has received increased attention, and several field tests and applications of 

bioaugmentation have been reported. Venosa et al. (1992) conducted a field test in Prince 

William Sound following the Exxon Valdez spill to investigate the effectiveness of two 
9 

commercial microbial products vis-à-vis natural attenuation and nutrient addition alone. These 

products were selected based on a previous laboratory study (Venosa et al., 1991). This field trial 

failed to demonstrate enhanced oil biodegradation by these products. No biostimulation 

occurred in the nutrient control plots either. There were no significant differences between any of 

the treatment and control plots during the 27-day trial period. However, the site where the 

project took place (Disk Island) was characterized as having highly weathered (degraded) oil and 

very calm waters, so dissolved oxygen may have been limiting, thus precluding effective 

biodegradation by any means. 

One approach in overcoming the competition problem was proposed by Rosenberg et al. 

(1992). They developed a product that combined a polymerized ureaformaldehyde fertilizer, 

which they called F-1, with a selected oil-degrading culture capable of using this fertilizer as a 

nitrogen source. Thus, the culture had a selective advantage over the indigenous population 

unable to utilize F-1 as nutrient source. A field trial conducted at an Israeli beach showed that 

this approach seemed to be successful in enhancing oil biodegradation. However, conclusions 

were confounded by the lack of adequate controls in the study (Swannell et al., 1996; Venosa, 

1998). 

To evaluate the effectiveness of two commercial bioaugmentation products in an 

estuarine environment, a field trial was carried out in a Texas coastal wetland by a research 

group from Texas A&M University (Simon et al., 1999; Townsend et al., 1999). The two 

products were selected based on a previous laboratory efficacy test, in which four out of twelve 

products showed an enhancement of oil biodegradation with significantly higher degradation 

rates of alkanes and aromatics when compared to a nutrient control (Aldrett et al., 1997). The 21-

plot site, named San Jacinto Wetland Research Facility (SJWRF) has been used for a series of 

studies on oil spills and their countermeasures. In this study, four treatment strategies were 

examined: an oiled control, biostimulation with inorganic nutrient addition (diammonium 

phosphate) , and commercial bioaugmentation with 2 different products. Arabian medium crude 

oil was selected in this test and the 21 plots each measuring 5 x 5 m were arranged in a balanced, 

incomplete block experimental design. Oil constituents were determined using gas 

chromatography/mass spectrometry (GC/MS) and were normalized to 17α(Η), 21β(Η)-hopane to 

reduce the effects of sample heterogeneity and physical losses. The results showed that the 

addition of microbial products could not significantly enhance oil biodegradation rates. No 

differences were observed between treatments when comparing the first order biodegradation 

rate coefficients for the total target saturates, total target aromatics, and individual hydrocarbon 

target analytes. The authors also pointed out that one of the products (BP8) “did show 

consistently higher biodegradation rates, though the rates were not significantly different from 

the control.” Because this microbial product was applied with vendor supplied inorganic 

nutrients (Townsend et al., 1999), it is difficult to conclude whether the “consistently but 

insignificantly” higher rates resulted from the additions of the microbial components or the 

nutrient components. The fact that neither addition of bioaugmentation agents nor application of 

inorganic nutrients significantly enhanced oil biodegradation suggested that other factors, such as 

oxygen, could have been limiting oil degradation in that environment. 

Studies comparing the performance of bioaugmentation and biostimulation have 

suggested that nutrient addition alone had a greater effect on oil biodegradation than did the 

addition of microbial products when oxygen supply was not limited (Jobson et al., 1974; Lee et 
10 

al., 1997; Venosa et al., 1996). This is probably because the hydrocarbon-degrading population 

is rarely a limiting factor as compared to the nutrients since the size of the hydrocarbondegrading bacterial population usually increases rapidly in response to oil contamination. One of 

the first comprehensive field tests evaluating various bioremediation approaches to enhance oil 

biodegradation was carried out in a soil environment in northwest area of Canada in early 1970s 

(Jobson et al., 1974). A randomized block design was used to examine the effects of four 

treatments (control, inorganic fertilizer application, ; addition of a microbial culture alone , and 

combined fertilizer and microbial culture addition) over a 308-day time period. The microbial 

culture was grown in the laboratory and consisted of several genera of oil-degrading bacteria 

(Flavobacterium and Cytophoga sp., Pseudomonas sp., Xanthomonas sp., Alcaligenes sp., and 

Arthrobacter sp.). The study showed that the nutrient application resulted in a significant 

stimulation of bacterial numbers and in the degradation rate of n-alkane components of the crude 

oil. The application of the microbial agent, however, resulted in only a slightly enhanced 

degradation rate of n-alkane components of chain lengths C20 to C25. 

A field study conducted on a sandy beach in Delaware also showed that addition of a 

microbial inoculum did not enhance oil biodegradation more than addition of inorganic nutrients 

alone (Venosa et al., 1996). A randomized block design was used in this study to assess the 

effects of three treatments: a no-nutrient control (natural attenuation), addition of water-soluble 

nutrients, and addition of water-soluble nutrients supplemented with a natural microbial 

inoculum from the site. No significant differences were observed between plots treated with 

nutrients alone and plots treated with nutrients and the indigenous inoculum, suggesting that 

supplementation of the natural population with indigenous cultures from the same site still did 

not result in further enhancement over simple nutrient addition on marine shorelines. The authors 

also indicated that this conclusion could be extended to include exogenous microbial inocula or 

commercial microbial agents because “if indigenous cultures do not accelerate the degradation 

rates, organisms enriched from different environments, grown in the laboratory, and not 

acclimated to a particular climatic or geographic location should be even less able to compete 

with the natural population.” 

Lee et al. (1997) conducted a 129-day field trial to compare the effect of four treatments 

on biodegradation of weathered Venture Condensate on a sandy beach in Nova Scotia, Canada. 

The four treatments (control, inorganic nutrient addition, a commercial bioremediation product, 

and addition of inorganic nutrients along with bioremediation product) as well as an unoiled 

control were replicated in a complete block design using 20 enclosures or plots. C2-chrysene 

was used as the normalizing biomarker due to the low concentration of hopane in the condensate. 

PRP (PetrolRem, Inc.) was selected to be the representative commercial bioremediation agent in 

this study. This product is no longer listed in the current NCP Product Schedule. According to 

Lee et al. (1997), PRP contains mineral nutrients and nonpathogenic bacteria within spherical 

particles made from plant derived natural products (beeswax) and exhibits both bioaugmentation 

and biostimulation properties. The agricultural fertilizer used in this study was a mixture of 

granular forms of ammonium nitrate (N:P:K: 33-0-0) and triple super phosphate (N:P:K: 0-46-0). 

The study showed that an average of 11.0% of the n-alkanes remained in the oiled control plots, 

and only 0.1% of the oil remained in the enclosures treated with inorganic nutrients alone; 5.4% 

of the alkanes were found in the plots treated with inorganic nutrients and PRP, and 25.3% 

remained in the plots treated with PRP alone. The results indicate that periodic addition of 

inorganic nutrients was the most effective strategy for enhancing oil degradation and that the full 
11 

potential of the bioremediation product was limited by nutrient availability. This field trial 

demonstrated that adding the bioremediation product did not perform better in terms of 

enhancing alkane degradation than applying inorganic agricultural fertilizers alone. 

Several other possible reasons for the failure of inocula in degrading contaminants in 

nature were summarized by Goldstein et al. (1985), which include: (1) the concentration of the 

contaminant may be too low to support the growth of the inoculated species, (2) the natural 

environment may contain substances inhibiting growth or activity of the inocula, (3) the growth 

rate of the inoculated species may be limited by predation such as protozoa, (4) the added species 

may use other substrates in nature rather than the targeted contaminants, and (5) the seeded 

microorganisms may be unable to move through the pores of the sediment to the contaminants. 

A few field trials did claim success in demonstrating the effectiveness of oil 

bioaugmentation, such as using Alpha BioSeaTM (Alpha Environmental, Inc.) to treat the 

Angolan Palanca crude oil spilled from Mega Borg off Texas coast (Mauro and Wynne, 1990; 

Swannell et al., 1996) and using TerraZymeTM (Oppenheimer Biotechnology) in enhancing 

biodegradation of a heavy oil spilled from Nakhodka in Japan (Tsutsumi et al., 2000). However, 

the success of these studies was based on either visual observation (i.e. the Mega Borg study) or 

digital photographic image analysis (i.e., the Nakhodka study). No comprehensive monitoring 

program was used to verify the oil was indeed removed through enhanced biodegradation. The 

two products basically contain the same bacterial cultures and nutrients (Hozumi et al., 2000). 

The observed visual effects might have been due to physical or chemical processes such as 

surfactant action associated with the products (Swannell et al., 1996) or sinking. 

All these peer-reviewed journal articles show that even though the addition of 

microorganisms may be able to enhance oil biodegradation in the laboratory, the effectiveness of 

bioaugmentation has not been convincingly demonstrated in the field. Actually, most field 

studies indicated that bioaugmentation is not effective in enhancing oil biodegradation in inland, 

estuarine, and marine environments. It appears that in most environments, indigenous oildegrading microorganisms are more than sufficient to carry out oil biodegradation if nutrient 

levels and other adverse environmental conditions do not limit them. 

2.3 Application of Biostimulation Products 

Biostimulation involves the addition of rate-limiting nutrients to accelerate the 

biodegradation process. In most shoreline ecosystems that have been heavily contaminated with 

hydrocarbons, nutrients are likely the limiting factors in oil biodegradation. The one exception is 

wetlands. If oil has penetrated wetland or marsh sediment to any appreciable extent, the impact 

zone is anoxic or anaerobic, and oxygen limitation will be the predominant mechanism 

precluding effective treatment. Theoretically, approximately 150 mg of nitrogen and 30 mg 

phosphorus are consumed in the conversion of 1 g of hydrocarbon to cell material (Rosenberg 

and Ron, 1996). Therefore, a commonly used strategy has been to add nutrients at concentrations 

that approach a stoichiometric ratio of C:N:P of 100:5:1. However, the practical use of these 

ratio-based strategies remains a challenge. Particularly, in marine shorelines, maintaining a 

certain nutrient ratio is impossible because of the dynamic washout of nutrients resulting from 

the action of tides and waves. A more practical approach is to maintain the concentrations of the 

limiting nutrient or nutrients within the pore water at an optimal range (Bragg et al., 1994; 
12 

Venosa et al., 1996). It is overwhelmingly evident from the literature that common agricultural 

fertilizers would be the first choice of nutrient additives since they are both inexpensive and 

readily available. However, because water-soluble nutrients are amenable to rapid washout, 

attempts have been made to design nutrient delivery systems that overcome the washout 

problems and to enhance nutrient availability for oil biodegradation. As a result, a few 

commercial biostimulation products have been developed. Field studies on both common 

agriculture fertilizers and commercial biostimulation agents are reviewed in the following 

section. 

2.3.1 Common agricultural fertilizers 

2.3.1.1 Water-soluble fertilizers 

Commonly used water-soluble nutrient products include mineral nutrient salts (e.g. 

KNO3, NaNO3, NH4NO3, K2HPO4, MgNH4PO4), and many commercial inorganic fertilizers. 

They are usually applied in the field through the spraying of nutrient solutions or spreading of 

dry granules. This approach has been effective in enhancing oil biodegradation in many field 

trials (Swannell et al., 1996; Venosa et al., 1996). One of the early field trials using common 

commercial fertilizers was carried out in Spitsbergen, Norway in 1976 (Sendstad, 1980). 

Forcados unweathered crude oil was released at a rate of 10 L/m2 on each of two 10 m2 plots. 

One plot served as an oiled control, and the other was treated with an unspecified commercial 

fertilizer at a concentration of 0.1 kg/m2

. A marked increase in microbial respiration rate was 

observed in the fertilized plot compared to the control plot, suggesting that the application of 

fertilizer stimulated oil degradation. However, the conclusion was questionable due to the 

inadequate control and the lack of replicate plots in this study (Venosa, 1998). 

Researchers from Fisheries and Oceans-Canada (Lee and Levy, 1987; Lee and Levy, 

1989; Lee and Levy, 1991; Lee and Trembley, 1993; Lee et al., 1995; and Lee et al., 1997) 

conducted a series of field tests to investigate the effect of different types of fertilizer and 

different delivery strategies in a low energy, sandy beach or in a salt marsh. Their studies 

demonstrated that biostimulation using periodic addition of inorganic fertilizers (ammonium 

nitrate and triple super phosphate) increased the rate of oil removal from beaches as measured by 

changes in oil composition relative to conserved biomarkers such as C2-chrysene and/or the 

decline in the n-C17/pristane and n-C18/phytane ratios (Lee and Levy, 1987 and 1989). Another 

study involved periodic addition of water-soluble fertilizer granules (ammonium nitrate and 

triple super phosphate) in an attempt to enhance biodegradation of waxy crude oil in a lowenergy, sandy beach and in a salt marsh (Lee and Levy, 1991). Two concentrations of the 

NH4NO3 were tested (0.34 and 1.36 g/L sediment). The oil used was Terra Nova crude at two 

different levels (0.3 and 3.0%). Results from the sandy beach showed that at the lower level of 

oil contamination, no enhancement by fertilizer was achieved. However, at the higher oil 

contamination level, substantial oil degradation occurred in the fertilized plots compared to the 

unfertilized ones. Results in the salt marsh were the exact opposite. Enhancement by fertilizer 

was significant at the 0.3% contamination level, but no enhancement occurred at 3% oil 

contamination, which was attributed to the penetration of oil into the anaerobic zone where little 

degradation is expected. Another field study conducted by Lee et al. (1995) compared the 

performance of inorganic nutrients with organic fish bone-meal fertilizer. These results showed 

that the organic fertilizer had the greatest effect on microbial growth and activity due to the 
13 

presence of a readily biodegradable form of carbon in the bone meal, while the inorganic 

nutrients were much more effective in stimulating crude oil biodegradation. 

Recent studies found that the oil biodegradation rate depends on the nutrient 

concentrations in the pore water of the sediments, which provides important guidance for 

nutrient applications (Bragg et al., 1994; Venosa et al., 1996). This finding may also explain 

why some earlier trials failed to demonstrate the effectiveness of nutrient application since the 

nutrient concentrations in the interstitial pore water had not been monitored and controlled in 

most of these studies. As mentioned earlier, the Delaware field study compared the effectiveness 

of biostimulation with inorganic mineral nutrients with that of microbial inoculation in 

enhancing the removal of crude oil. Venosa et al. (1996) found that maintenance of a threshold 

nitrogen concentration of 1-2 mg N/L in the interstitial pore water would result in close to 

maximum hydrocarbon biodegradation in a sandy beach. Another important conclusion from this 

study was that background nutrient concentrations at the contaminated site should be a 

determining factor in the decision to apply bioremediation. The background nitrogen 

concentration at the Delaware beach was high enough to permit close to maximum hydrocarbon 

biodegradation without the need to apply additional fertilizer despite the enhancement observed 

from nutrient addition. The enhanced effect, although statistically significant, was not substantial 

enough to have warranted a decision to implement bioremediation on a full-scale basis had there 

been a real spill at this site. This demonstrates that nutrient amendment might not always be 

necessary if sufficient nutrients are naturally present at a spill site in high enough concentrations 

to perform natural cleanup. 

This conclusion is mitigated somewhat by the need to consider the resources at risk. For 

example, every spring in the Delaware Bay, horseshoe crabs come ashore to mate and lay eggs in 

the intertidal zone of the beaches. Migratory birds making their way from South America to 

Arctic Canada stop at this location to feed on the horseshoe crab eggs deposited in the sand. If an 

oil spill were to take place a few weeks before this feeding season occurs, biostimulation might 

be warranted despite the already high natural concentrations of nutrients present in the bay. Any 

amount of acceleration of the disappearance of oil in order to protect these sensitive bird 

populations would be justified. If a similar spill occurred in July, however, then bioremediation 

would likely not be justified since the natural attenuation rate is expected to be high enough to 

allow sufficient rates of biodegradation to take place with little likelihood of exposure of 

sensitive species to the oil spill. 

Field studies conducted in wetland environments showed that biostimulation was 

ineffective in treating certain oil-contaminated salt marshes or freshwater wetlands due to 

oxygen limitation (Garcia-Blanco et al., 2001; Shin et al., 1999; Venosa et al., 2002). In 1999 

and 2000, a field study was conducted on the shoreline of the St. Lawrence River (Garcia-Blanco 

et al., 2001; Venosa et al., 2002). The experimental design was similar to the one used on the 

marine shoreline in Delaware Bay (Venosa et al., 1996). The four oiled treatments included: (A) 

a natural attenuation control plot with no amendments; (B) a plot receiving ammonium nitrate 

and orthophosphate nutrients but with the wetland plants continually cut back to ground surface 

to suppress photosynthetic activity and growth; (C) a plot receiving the same nutrients as 

Treatment B but with the plants left intact, and (D) a plot similar to Treatment C but with only 

nitrate (no ammonium) serving as the nitrogen source. The results demonstrated that with respect 

to biodegradation of total alkanes and PAHs during the first 21 weeks of the investigation as 
14 

measured by GC/MS analysis, only about 35% biodegradation occurred in all treatments on 

average, and no significant differences among any of the treatments were observed (p > 0.05). 

The study also found that better biodegradation occurred in surface samples in plots where the 

plants had been removed than in any of the core samples because of the oxic nature of the 

surface and the lack of competition for nutrients by the plant species. The authors concluded that 

nutrient amendment of an oil-contaminated freshwater wetland where significant penetration of 

oil has taken place into the sediment has limited potential for enhanced cleanup of the 

contamination. A similar result was obtained from a field trial conducted in a Louisiana salt 

marsh (Shin et al., 1999), in which natural attenuation of crude oil was as effective as nitrogen 

(NH4NO3) amendment, and oxygen availability appeared to control the oil biodegradation 

process in salt marshes. 

All these results suggest that the success of biostimulation is case specific, depending on 

oil properties, the nature of the nutrient products and the characteristics of the contaminated 

environments. When oxygen is not a limiting factor, one of keys for the success of oil 

biostimulation is to maintain an optimal nutrient level in the interstitial pore water. To achieve 

this under field conditions, especially in many estuarine and marine environments, frequent 

nutrient applications are required when using water-soluble fertilizers, therefore, resulting in 

more labor-intensive, costly, and physically intrusive operations. 

2.3.1.2 Slow-release fertilizers 

Use of slow release fertilizers is one of the approaches used to overcome washout 

problems and provide continuous sources of nutrients to oil contaminated areas. Slow release 

fertilizers are also readily available nutrient products normally in solid forms that consist of 

either relatively insoluble nutrients or water-soluble nutrients coated with hydrophobic materials 

such as paraffin or vegetable oils. This approach may also cost less than adding water-soluble 

nutrients due to the need for less frequent applications. Slow release fertilizers have shown some 

promise in oil bioremediation studies and applications. For example, following the Exxon Valdez

accident, a slow-release granular fertilizer, Customblen (Sierra Chemical Co.), was chosen as 

one of the bioremediation agents to apply over 120 km of the oil-contaminated shorelines during 

1989 and 1990. This fertilizer consists of vegetable oil coated calcium phosphate, ammonium 

phosphate, and ammonium nitrate (N:P:K ratio 28-8-0). The results showed that Customblen 

performed well on some of the shorelines of Prince William Sound, particularly in combination 

with an oleophilic fertilizer, Inipol EAP22 (see next section) (Atlas, 1995; Pritchard et al., 1992; 

Swannell et al., 1996).

Several field studies have been carried out to evaluate the effectiveness of slow-release 

fertilizers on enhancing oil biodegradation. A field test was carried out to evaluate the 

performance of bioremediation by nutrient amendments for treating a mixture of Forties Crude 

Oil and Heavy Crude Oil stranded on Bullwell Bay, Milford Haven, UK, after the grounding of 

the Sea Empress in 1996 (Swannell et al., 1999a&b). A randomized block design with triplicate 

treatments was used to test the efficacy of two biostimulation amendments: a weekly application 

of an inorganic nutrient solution (NaNO3 and KH2PO4) and a single application of a slow-release 

fertilizer. The slow release fertilizer pellets consisted of a mixture of inorganic nutrients (15-4.8-

13) with a coating derived from soya oil. Oil components were measured using GC/MS, and 

hopane was used as a biomarker. Results showed that the addition of both liquid inorganic 
15 

nutrients and the slow release fertilizer significantly stimulated natural oil biodegradation. After 

two months, the oil in the nutrient-amended plots was 37% more degraded than that found in the 

control plots. Because the slow-release fertilizer was much less labor-intensive to apply, the 

study concluded that the application of slow-release fertilizers might be a cost-effective method 

for treating low-energy, oil-contaminated shorelines. 

A field study conducted in a tropical marine wetland in Australia also showed promise 

for the application of slow-release fertilizers (Burns et al., 2000). In this study, four oiled 

treatments (two types of oils with and without the bioremediation treatments) and two unoiled 

controls (enclosure and ambient controls) were tested. Four replicate plots were used for each 

treatment in the salt marsh plots. The bioremediation treatment consisted of sprinkling Osmocote 

Tropical fertilizer at 0.15 kg m-2 40 hours after oiling. Other than total petroleum hydrocarbons 

(TPHs), individual alkanes were also analyzed using GC-FID, and phytane was used as a 

biomarker. The results indicated that although the predominant oil removal processes were 

evaporation and dissolution, the addition of the fertilizer to the salt marsh plots stimulated the 

degradation of the medium range crude oil (Gippsland), resulting in about 20% more oil loss as 

compared with the untreated plots after 9 months. However, the nutrient amendment did not 

significantly affect the rate of loss for the heavier Bunker C oil, confirming that the efficacy of 

bioremediation is somewhat dependent on the type of oil to be treated. 

Another field trial involving the application of a slow-release fertilizer was carried out on 

an Arctic beach (Prince et al., 1999). Four treatments (tilled, tilled & fertilized, fertilized, and 

oiled control) were evaluated on four unreplicated plots along a gravel shoreline contaminated 

with a fuel oil (IF-30) near Sveagruva, Norway. A series of applications of various nutrient 

products were performed for both fertilized plots during the first two months of study. These 

nutrient products included a mixture of water-soluble fertilizers, yeast extract, and a slow-release 

formulation (Inipol SP1, CECA, Paris La Defense), which contained 18% NH4 –N and 1% P as 

P2O5. By 399 days after the first application of the fertilizers, changes in the chemical oil 

compositions (ratio of phenanthrene to the dimethyl- and ethyl-phenanthrenes) suggested to the 

investigators that biodegradation was significant. However, the extent of this preferential 

removal of phenanthrene was not different among the two fertilized plots and the oiled control 

(no statistical analysis was possible because of the lack of replicate plots). The authors concluded 

that the biostimulation application was effective in enhancing oil biodegradation based only on 

increased microbial activity (oxygen consumption) and biomass growth. This conclusion, which 

is based on indirect evidence, may be somewhat questionable due to lack of replication in the 

experimental design and the attempt to determine too many factors in a limited number of tests, 

resulting in the confounding of different effects (e.g., the effect of yeast extract on enhancing 

oxygen consumption). 

The efficacy of biostimulation also depends on environmental factors such as 

temperature, shoreline energy, substrate, and background nutrient concentrations. A field study 

conducted by Lee et al. (1993) indicated that the effectiveness of specific nutrient formulations 

might be influenced by temperature conditions. The study investigated the efficacy of watersoluble inorganic fertilizers (ammonium nitrate and triple super phosphate) and a slow release 

fertilizer (sulfur-coated urea) to enhance the biodegradation of a waxy crude oil in a low energy 

shoreline environment. The results showed that at temperate conditions above 15°C, the slowrelease fertilizer appeared to be more effective in retaining elevated nutrient concentrations 
16 

within the sediments and enhancing oil degradation than water-soluble fertilizers. However, 

lower temperatures were found to reduce the permeability of the coating on the slow-release 

fertilizer, and as a result nutrient release rates were suppressed. Water-soluble fertilizers, such as 

ammonium nitrate, were recommended under these temperature conditions. 

Oudot et al. (1998) evaluated the influence of a slow-release fertilizer (Max-Bac, GraceSierra International) on the biodegradation rate of an Arabian Light crude oil contaminating an 

estuarine environment in the bay of Brest, France. A randomized block design with five replicate 

plots was used to examine the effects of two treatments (oiled control and fertilizer addition). 

The slow-release fertilizer (10% NO3-N, 12% NH4-N and 13% P2O5) was applied monthly over 

the 9 months field test. On average, 40% of the total oil, 83% of the aliphatics, and 55% of the 

aromatics were biodegraded in all the plots at the end of the experiment. No significant 

difference in oil biodegradation rates was observed between fertilized and non-fertilized plots 

based on GC/MS analysis using norhopane as the normalizing biomarker. These results were 

attributed to the high background levels of N and P at the study site. It was proposed that 

bioremediation by nutrient enrichment would be of limited use if background interstitial pore 

water levels of N exceed 1.4 mg/L, which is close to the levels found to be near optimum by 

Venosa et al. (1996). 

The physical forms of fertilizers are also important in selecting appropriate nutrient 

products. Field trials conducted following the Exxon Valdez spill evaluated two types of slow 

release nutrients: isobutylidene diurea (IBDU) briquettes and Customblen granules. The 

application of the briquettes was problematic in regards to buoyancy of the briquettes and 

redistribution by tide and wave action (Glaser, 1994; Glaser et al., 1991). The method used 

during the Exxon Valdez spill involved packing the briquettes in mesh bags tethered to steel bars 

driven into the beach subsurface. The poor distribution problem occurred by channeling of 

nutrients vertically down the beach rather than lateral spreading. In contrast, Customblen 

granules were evenly applied using a commercial broadcasting fertilizer spreader. Within two 

weeks after the fertilizer application, the area of cobble beach treated with Customblen appeared 

to be visibly cleaner than the untreated area (Pritchard et al., 1992). 

The major challenge for the application of slow-release fertilizers is how best to control 

the release rates so that optimal nutrient concentrations can be maintained in the pore water over 

long time periods. For example, if the nutrients are released too quickly, they will be subject to 

rapid washout and will not be a lasting source. On the other hand, if they are released too slowly, 

the concentration will never build up to a level that is sufficient to support rapid biodegradation 

rates, and the resulting stimulation will be less effective than it could be. The field trials on of the 

shorelines of Prince William Sound showed that on certain beaches, Customblen granules were 

apparently washed away before any significant enhancement of bioremediation was recorded 

(Swannell et al., 1996). A recent mesocosm study by Sveum and Ramstad (1995) showed that a 

slow release nutrient (Max Bac) failed to demonstrate enhancement of oil degradation because 

the nutrient release rate was too low to affect oil biodegradation. Clearly, proper application of 

slow release fertilizers could be a promising bioremediation strategy for stimulating oil 

biodegradation. 
17 

2.3.2 Commercial biostimulation agents 

Compared to microbial products, very few nutrient additives have been developed and 

marketed specifically as commercial bioremediation agents for oil spill cleanup. It is probably 

because common fertilizers are inexpensive, readily available, and have been shown effective if 

used properly. However, due to the limitations of common fertilizers (e.g., being rapidly washed 

out due to tide and wave action), several organic nutrient products, such as oleophilic nutrient 

products, have recently been evaluated and marketed as bioremediation agents. Four of the 15-

bioremediation agents listed on the NCP Product Schedule fall into this category (Table 2.1). The 

rationale for using oleophilic organic nutrients is that oil biodegradation mainly occurs at the oilwater interface, and since oleophilic fertilizers are able to adhere to oil and provide nutrients at 

the oil-water interface, enhanced biodegradation should result without the need to increase 

nutrient concentrations in the bulk pore water. This approach can also be used to overcome the 

problem of water-soluble nutrients being rapidly washed out. Field evaluation results for some 

of these products have been available in the peer-reviewed literature. 

2.3.2.1 Inipol EAP22 

Inipol EAP22 (Societe, CECA S.A., France) is currently listed on the NCP Product 

Schedule as a nutrient additive and probably the most well-known bioremediation agent for oil 

spill cleanup due to its use in Prince William Sound, Alaska. This nutrient product is a 

microemulsion containing urea as a nitrogen source, sodium laureth phosphate as a phosphorus 

source, 2-butoxy-1-ethanol as a surfactant, and oleic acid to give the material its hydrophobicity. 

The claimed advantages of Inipol EAP22 include: 1) preventing the formation of water-in-oil 

emulsions by reducing the oil viscosity and interfacial tension; 2) providing controlled release of 

nitrogen and phosphorus for oil biodegradation; 3) exhibiting no toxicity to flora and fauna and 

good biodegradability (Ladousse and Tramier, 1991). 

Following the Exxon Valdez spill, Inipol EAP22 was chosen as one of the nutrient 

products to use in the cleanup, and approximately 50,000 kg of nitrogen and 5,000 kg of 

phosphorus were applied over 120 km of the oil-contaminated shorelines during 1989 and 1990. 

Inipol EAP22 was selected also because it was the only commercially available bioremediation 

agent with large production capacity at the time other than common agricultural fertilizers 

(Pritchard et al., 1992). Visual observation seemed to suggest that the bioremediation agent 

worked (Pritchard and Costa, 1991). However, the “window pane effect” observed within 2 

weeks after application of Inipol to the beach was simply the result of oil having been lifted from 

the cobble and re-deposited in the interstitial sand matrix between and under the cobbles. 

Using hopane as the biomarker, Bragg et al. (1994) showed that fertilizer application 

accelerated the rate of oil removal by a factor of approximately five-fold compared to natural 

attenuation. However, conclusions on the effectiveness of bioremediation in the Exxon Valdez 

experience are somewhat questionable, in part because the flawed experimental design was not 

based on sound statistical principles (Venosa, 1998). Major flaws included the lack of 

replication, inadequate sampling procedures, unequal treatment of controls and treated plots, and 

an attempt to determine too many factors in a limited number of tests, resulting in the 

confounding of different effects. The lessons learned from the Exxon Valdez project led to the 
18 

replacement of “post Exxon Valdez excitement” with more scientifically-valid approaches 

(Mearns, 1997). 

Extensive studies have been carried out under various field conditions on the efficacy of 

Inipol EAP 22 and have produced mixed results (Lee and Levy, 1989, Ladousse and Tramier, 

1991; Sveum and Ladousse,1989). Lee and Levy (1989) conducted a field trial to investigate the 

effect of different types of fertilizers on enhancing the biodegradation of Scotian Shelf 

condensate and Hibernia crude oil. The study occurred in the intertidal zone of a low-energy 

sandy beach in Nova Scotia, Canada. The two nutrient products tested were Inipol EAP22 and a 

mixture of 10:1:0 agricultural fertilizer. The study demonstrated that biostimulation using 

periodic addition of the inorganic fertilizer increased the rate of oil removal from beaches as 

measured by changes in oil composition relative to conserved biomarkers such as C2-chrysenes 

and/or the decline in the n-C17/pristane and n-C18/phytane ratios. In contrast, the addition of the 

oleophilic fertilizer, Inipol EAP 22, did not enhance oil degradation. 

The effectiveness of Inipol EAP22 also depends on the characteristics of the 

contaminated environment, such as action of wave and tide, and the effect of different sediment 

types. Based on several field studies on the effectiveness of Inipol EAP22, Sveum et al. (1994)

indicated that this oleophilic fertilizer appeared to be more effective than water-soluble fertilizers 

when the spilled oil resided in the intertidal zone. But they have no advantages in enhancing oil 

biodegradation in the supratidal zone where water transport is limited. Inipol EAP 22 was found 

to be more effective in coarse sediments than in fine sediments due to the difficulty in 

penetration for the oleophilic fertilizer in fine sediments (Sveum and Ladousse, 1989), although 

stronger evidence is needed to confirm this suggestion. Variable results have also been produced 

regarding the persistence of oleophilic fertilizers. Some studies showed that Inipol EAP 22 could 

persist in a sandy beach for a long time under simulated tide and wave actions (Santas and 

Santas, 2000; Swannell et al. 1995). Others found that Inipol EAP22 was rapidly washed out 

before becoming available to hydrocarbon-degrading bacteria (Lee and Levy, 1987; Safferman, 

1991). 

2.3.2.2 BIOREN 

Researchers from European EUREKA BIOREN program recently conducted a field trial 

in an estuary environment to evaluate the effectiveness of two bioremediation products 

(BIOREN 1 and 2) (Le Floch et al., 1997 and 1999). The EUREKA BIOREN project was an 

international effort to develop commercial nutrient products able to enhance hydrocarbon 

biodegradation on contaminated shorelines. The two nutrient products are derived from fish 

meals in a granular form with urea and super phosphate as nitrogen and phosphorus sources and 

proteinaceous material as the carbon source. The major difference between the two formulations 

was that BIOREN 1 also contained a biosurfactant. To reduce the effect of physical removal of 

oil and nutrients, the study was conducted on a sheltered sandy beach in a small estuary in 

Brittany, France. A light Arabian crude oil was used as the model contaminant in this field trial. 

Four treatments (unoiled control, oiled control, BIOREN 1, and BIOREN 2) were randomly 

assigned to four experimental plots (5m x 5m), and four smaller oiled control plots (2m x 3m) 

were also set up along side the treated plots. The nutrient products were applied twice over the 4-

month study (once immediately after oiling and again two weeks after). The results showed a 

“starter effect” for the BIOREN 1 formulation: biodegradation was significantly enhanced during 
19 

the first five weeks of the experiments based on the analysis of the nC17/pristane and 

nC18/phytane ratio. However, after five weeks, the enhancement was reduced and “significant 

differences” were no longer observed between treatments at the end of the test. The authors 

concluded that the BIOREN 1 hold promise for accelerating microbial activity immediately after 

an accidental oil spill. 

The results seem to suggest that the biosurfactant in BIOREN 1 was the most active 

ingredient that contributed to the increase in oil degradation rates since BIOREN 2, which 

contained no surfactant, was not effective in that respect. The biosurfactant could have 

contributed to greater bioavailability of hydrocarbons to microbial attack. It would have been 

better if the investigators had used replicate treatments because this would have enabled them to 

calculate experimental error. Results would have been stronger in support of conclusions made. 

Other studies on the effect of similar organic fertilizers derived from natural products 

also yielded mixed results. A field trial conducted by Lee et al. (1995a) compared the 

performance of inorganic nutrients with an organic fish bone-meal fertilizer on the 

biodegradation rates of Venture Condensate in a sandy beach environment. The results showed 

that the organic fertilizer had the greatest effect on microbial growth and activity, while the 

inorganic nutrients were much more effective in stimulating crude oil biodegradation. One of the 

problems with these types of fertilizers is that they contain organic carbon, which may be 

biodegraded by microorganisms in preference to petroleum hydrocarbons (Lee et al., 1995a; 

Swannell et al., 1996), which may lead to undesirable anoxic conditions (Lee et al., 1995b; 

Sveum and Ramstad, 1995). 

2.3.2.3 Oil Spill Eater II® (OSE II) 

Oil Spill Eater II® (Oil Spill Eater International, Corp.) is another nutrient product listed 

on the NCP Schedule (U.S. EPA, 2002). This product is listed as a nutrient /enzyme additive 

and consists of “nitrogen, phosphorus, readily available carbon, and vitamins for quick 

colonization of naturally occurring bacteria”. A field demonstration was recently carried out at a 

bioventing site in a Marine Corps Air Ground Combat Center (MCAGCC) in California to 

investigate the efficacy of OSEII for enhancing hydrocarbon biodegradation in a fuelcontaminated vadose zone (Zwick et al., 1997). The selection of OSEII was base on the findings 

from a previous microcosm study, in which various amendments were evaluated by monitoring 

microbial respiration using soils collected from the site. The results suggested that fertilizer 

amendment, not bioaugmentation, might be cost-effective for accelerating biodegradation rates at 

this field site (Alleman and Foote, 1997). Although groundwater environments and subsurface 

hydrocarbon contamination are generally not within the scope of this review, this article was 

included because it is the only peer-reviewed paper available on a NCP-Schedule-listed 

bioremediation nutrient additive, other than numerous publications on Inipol EAP 22. 

At beginning of the test, air was pumped into vent wells for 36 hrs to achieve oxygen 

concentrations of over 20% at the site. Groundwater was injected at 20 ft below ground surface 

(bgs), while OSE II solution was pumped to 30-40 ft. bgs through two monitoring points. OSE II 

was also injected into two monitoring points in an uncontaminated area of the site to act as 

product controls. An On-line Environmental Monitoring System (OEMS) was used to conduct 

in-situ measurement of O2 and CO2 at depths of 10, 20, 30, and 40 ft bgs. Hydrocarbon 
20 

degradation rates (as mg hexane per kg of soil per day) were calculated based on oxygen 

utilization rate, and CO2 data were used to verify biodegradation. The effect of OSE II was 

monitored for about three months after the initial application and the results were compared to 

those obtained before the OSE II injection when irrigation was conducted for over a year. 

The oxygen and CO2 data showed that an increase in respiration rates occurred shortly 

after the addition of OSE II, especially at the 30-ft bgs level, indicating an increase in microbial 

activity as a result of OSE II addition. The extent of the rate increase was much higher than that 

measured at the uncontaminated background site receiving OSE II, suggesting the BOD 

associated with the product may not be the main cause for the increase in the respiration rates at 

the contaminated site. However, the respiration rates at both 10 ft bgs (oiled-control) and 20 ft 

bgs (groundwater irrigation) levels at the contaminated site were also higher than the pre-test 

levels, suggesting that factors other than the OSE II addition might also be responsible for the 

increase in oxygen utilization rates. These factors could be the pre-aeration at the beginning of 

the study (the control site had not been pre-aerated as the test site was), changes in 

environmental conditions, or differences in geology at the various depths., No statistical analysis 

was carried out to test the significance of the findings in this study. Although respiration rates 

may be an indirect measure of product effectiveness, proof of effectiveness comes from 

measurement in decline of hydrocarbons, which was not discussed in the report. Although this 

field trial suggested that irrigation and OSE II addition might have enhanced microbial activities 

in the deeper soils at the site, the report was inconclusive in regards to direct evidence that 

hydrocarbons were degraded. 

In summary, the effectiveness of these various types of nutrient formulations will depend 

on the characteristics of the contaminated environment and of the formulations themselves. 

Slow-release fertilizers may be an ideal nutrient source if the nutrient release rates are well 

controlled. Water-soluble fertilizers are likely more cost-effective in low-energy and fine-grained 

shorelines where water transport is limited. Oleophilic fertilizers may be more suitable for use in 

high-energy and coarse-grained beaches or less accessible rocky outcroppings. Successful 

application of bioremediation products will always require appropriate experimental design, 

testing, and evaluation based on the specific conditions of each contaminated site.

2.4 Summary 

Peer-reviewed literature on the use of bioremediation products has clearly indicated that 

biostimulation, if used properly, could be a cost-effective treatment tool for cleaning certain oilcontaminated environments. Important findings and lessons learned from these studies are 

summarized as follows. 

• Bioaugmentation appears to have little benefit for the treatment of spilled oils in an open 

environment. Microbial addition has not been shown to work better than nutrient addition 

alone in many field tests. However, application of bioaugmentation products could still 

have some potential in the treatment of specific oil components or isolated spills in 

confined areas, although more evidence is still required to verify this notion. 

• Bioremediation with addition of nutrient products has been proven to be an effective tool 

to treat certain aerobic oil-contaminated marine shorelines. Typically, it is used as a 
polishing step after conventional mechanical cleanup options have been applied, although 

it could also be used as a primary response strategy if the spilled oil does not exist as free 

product and if the contaminated area is remote enough not to require immediate cleanup or 

not accessible by mechanical equipment. 

• Effectiveness of biostimulation is also highly site-specific. When oxygen is not a limiting 

factor, one of the key factors for success is to maintain an optimal nutrient level in the 

interstitial pore water. In other words, background nutrient concentrations at the 

contaminated site should be a determining factor in the decision to apply bioremediation, 

and biostimulation might not always be necessary if sufficient nutrients are naturally 

present at a spill site in high enough concentrations to permit effective microbial treatment. 

Availability of oxygen is often the limiting factor in wetland environments, where addition 

of nutrient products has not been successful in enhancing oil biodegradation. If the oil is in 

the aerobic zone of a wetland sediment (upper few mm) and if background nutrients are 

low, then biostimulation may still be an effective cleanup strategy. Even if oil has 

penetrated into the anaerobic zone, biostimulation may at least allow for faster recovery of 

the wetland vegetation. 

• Nutrient products have shown variable effectiveness, depending on oil properties, the 

nature of the nutrient products, and the characteristics of the contaminated environments. 

In general, commercial oleophilic nutrient products have not shown clear advantages over 

common agricultural fertilizers in stimulating oil degradation. 

• As this review has pointed out, many field tests have not been properly designed, well 

controlled, or correctly analyzed, leading to skepticism and confusion among the user 

community when selecting response options (Venosa, 1998). Future field studies should 

devote more energy and investment to adopting scientifically valid approaches and 

acquiring the highest quality data possible. 

21 
22 

3 Assessment of Oil Bioremediation Products: Non-Peer Reviewed Literature 

As indicated in the previous chapter, only limited field studies and applications of 

bioremediation products have been reported in the peer-reviewed literature. In an attempt to 

better document the potential and understand the scope of the actual use of bioremediation 

products, a thorough search of non-peer-reviewed and ‘gray’ literature pertaining to the use of 

bioremediation agents in response to oil spills in inland, estuarine, and marine environments has 

also been conducted. A comprehensive review of this information is presented in this chapter, 

which includes the review of government agency reports, vendor reports, and vendor client 

reports. Section 3.1 presents a thorough review of field trials of bioremediation products based 

on various government agency reports. Section 3.2 summarizes the results of an information 

collection effort from manufacturers and vendors of bioremediation products and provides an 

assessment of the efficacy of some bioremediation agents based on the gathered information. 

The potential of using bioremediation products in the areas of non-point source such as storm 

water runoff countermeasures and bilge oil treatment will be discussed in Section 3.3. 

3.1 Government Agency Reports 

Many government agencies have been involved in various aspects of oil spill cleanups. 

At the federal level, oil spill response planning is coordinated through the U.S. National 

Response Team (NRT, www.nrt.org). This is an interagency group made up of 16 federal 

agencies and co-chaired by the EPA and the U.S. Coast Guard (USCG), each with 

responsibilities and expertise in various aspects of spill response. For example, EPA is in charge 

of coordinating oil spill response in inland environments; the USCG coordinates oil spill 

prevention and response in the coastal zone; and National Oceanic and Atmospheric 

Administration (NOAA) as well as EPA provide national coordination with respect to scientific 

support. In this project, many of the governmental agencies that have likely been involved in 

evaluating and using bioremediation approaches in oil spill responses were contacted and/or their 

publication websites were searched. These governmental agencies include U.S. EPA Oil Spill 

Office, USCG, NOAA, Department of Energy, Department of Interior, the U.S. Navy, U.S. 

Army Corps of Engineers, and various state agencies. From this search, a number of government 

reports pertaining to the use of commercial bioremediation products were obtained. Although 

some of this literature has already been covered in other reviews, such as Swannell et al. (1996), 

Venosa (1998), and Zhu et al. (2001), they will still be discussed within the context of 

effectiveness of commercial bioremediation agents. Again, all this literature will be reviewed 

based on the two main bioremediation approaches, bioaugmentation and biostimulation. 

3.1.1 Application of bioaugmentation products 

Several field studies or applications on the use of commercial bioaugmentation agents 

have been published in government agency reports with mixed results. Mearns (1991) reported 

on a bioaugmentation field test of an oiled marsh in an estuary environment of upper Galveston 

Bay, Texas. The spill occurred in August 1990, when a collision occurred between three Apex 

Barges and the Greek tanker Shinoussa. The test was conducted 8 days after the spill, which 

resulted in the release of approximately 700,000 gallons of catalytic feedstock (a partially refined 

oil). Four plots were used in selected areas of Marrow Marsh: two treated with a commercial 

bioaugmentation product (Alpha BioSeaTM, Alpha Environmental, Inc.), and two left untreated 
23 

as controls. The product consisted of a bacterial culture in a cornstarch carrier and a 

nutrient/micronutrient mixture. It was prepared by premixing with ambient brackish water, and a 

diluted stock solution was sprayed on the two marsh test plots. Oil constituents were determined 

using GC/MS and the extent of biodegradation was measured by the decline in the nC18/phytane ratio in this study. During only a 4-day monitoring period, results of the chemical 

analysis indicated no apparent difference in the extent of oil biodegradation between treated and 

untreated plots, although no statistical analysis was performed. Mearns speculated that either the 

oil had too low a content of degradable components or insufficient bioremediation agent was 

used. However, the major deficiency of this study was that 4 days were insufficient for reaching 

any convincing conclusion on the effectiveness of bioremediation. Biodegradation is a relatively 

slow process, and usually weeks or months are needed before significant microbial activity may 

take effect. Mearns et al. (1993) later summarized some lessons learned from this experiment, 

which included that bioremediation is not a rapid response tool, experimental design should meet 

basic statistical requirements, and more comprehensive monitoring is needed to demonstrate the 

efficacy of treatment. 

In another NOAA report, Hoff (1991) described a bioaugmentation project along a 

California shoreline. On October 31, 1990, a well blowout offshore of Seal Beach, CA, released 

approximately 400 gallons of crude oil resulting in the contamination of 2-3 acres of marsh 

grasses in the Seal Beach National Wildlife Refuge. A bioremediation treatment that consisted of 

the hand spraying of a microbial product used in wastewater treatment plants (INOC 8162) and a 

commercial fertilizer (Miracle Gro 30-6-6) was carried out one week after the incident, followed 

by an application of the fertilizer alone two weeks later. Oil degradation was monitored based on 

the measurements of 14C-mineralization and most probable number counts of bacteria. No 

difference was observed between treated and untreated salt marsh plots 35 days after the initial 

treatment, suggesting neither bioaugmentation nor biostimulation with nutrient addition worked 

in this case. However, no reporting of nutrient concentrations was provided, so it was difficult to 

determine if sufficient nutrients were available to allow biodegradation to take place. 

Nonetheless, the result is consistent with the finding by others that oxygen availability is likely 

the limiting factor for oil biodegradation in wetland environments (Shin et al., 1999; Simon et 

al., 1999; Venosa et al., 2002). 

A pilot-scale project was carried out recently to test the efficacy of a bioremediation 

procedure in treating soils contaminated by petroleum oils and lubricants (POLs) at an Army 

installation at Fort Hood, TX (U.S. Army, 1999). POLs are common contaminants on 

Department of Defense (DoD) installations, and the U.S Army is increasingly being asked to 

comply with more stringent regulations for disposal of these wastes. The treatment procedure 

tested in this study included the addition of a commercial bioremediation agent, BET BioPetro 

(BioEnviroTech, Inc.), at 1 lb/yd3

 of contaminated soil and an agricultural fertilizer (24-8-8) at a 

rate of 0.5 lb/yd3. After the addition of both microbial and nutrient products, the contaminated 

soil was tilled and then watered at a rate of 1.5 in/week. BET BioPetro is one of the 

bioremediation agents listed on the NCP Product Schedule (Table 1.1). According to the 

vendor’s description, BET BioPetro is “a powder containing granules of bacterial product 

formulated to provide performance in the bioremediation of heavy refined and crude 

hydrocarbon contaminants in both soil and water environments” (U.S. EPA, 2002). In this field 

trial, the bioremediation procedure described above was tested for six months at three sites 

contaminated by JP8 fuel oil, and the results were successful in terms of oil degradation based on 
24 

TPH analysis. For example, six months after the initial treatment was applied, TPH 

concentrations decreased dramatically from the initial values of 10,100 – 13,100 mg/kg to the 

final results of 195 – 1,170 mg/kg at Site 2. Treated soils were able to meet the reuse 

requirements for the final disposal to sanitary landfills. Unfortunately, no control was set up 

during this study; therefore, no conclusion could be reached in regard to whether this apparent 

drop in oil concentration was due to the addition of BET BioPetro or any other treatments (i.e., 

nutrient addition, tilling, or watering). The lesson from this project again demonstrates how 

critical a proper experimental design is in testing the effectiveness of bioremediation. 

Bioremediation experience at U.S. Navy’s Naval Facilities Engineering Service Center 

(NFESC) also suggested that bioaugmentation is generally not needed for treating fuel/oil 

contaminated soils because of the ubiquity of hydrocarbon degraders in nature. However, 

according to personnel at the NFESC, microbial amendment may have limited use for treating 

specific contaminants or in specific environments. An example was given of the potential 

usefulness of a specific microbial product. A bioremediation project that involved adding a 

commercial bioaugmentation agent to a biopile was conducted at a naval air station (NAS) in 

Fallon, Nevada in 2002 (personal communication with personnel at the NFESC). The soils were 

contaminated with a mixture of fuels (mostly aged gasoline and JP-5). Sulfate and sulfide levels 

in these soils were also very high. When aeration was imposed by means of a vacuum pump, the 

soil temperature increased dramatically to about 70°

C, probably due to high oxidation rates of the 

sulfides. The naval investigators surmised that because of the high temperatures caused by the 

forced aeration conditions, bioaugmentation might be helpful to enhance hydrocarbon 

biodegradation in a subsequent treatment step. A bioaugmentation treatment was carried out by 

Pintail Systems (Denver, CO), which involved the application of a product consisting of a 

mixture of microbial isolates from soils at the site plus some cultures isolated from an acid mine 

drainage site. Three months after the application of the microbial product, TPH concentrations in 

the soils dropped dramatically from pre-treatment levels of about 2,000 mg/kg to about 200 

mg/kg. Again, no control pile was established to help demonstrate the effectiveness of the 

bioaugmentation treatment. Therefore, this result in no way proves or even suggests that the 

bioaugmentation product used was effective. It is common that compost and biopiles can be 

highly effective in treating organic waste products, and temperatures that are attained can reach 

very high levels. 

3.1.2 Application of biostimulation products 

Several government agency reports of field experience with evaluation and use of 

commercial nutrient products are available. Included among them are several articles that cover 

bioremediation experience following the Exxon Valdez oil spill (Bragg et al., 1992; Pritchard et 

al., 1991; Venosa et al., 1990). Field studies on the use of nutrient products have produced 

mixed results. Hoff (1991) summarized a field trial conducted by Exxon Research & Engineering 

Company with technical support from DuPont Environmental Remediation Services, on Prall’s 

Island, New Jersey. The study was carried out between September and December 1990 to assess 

the effectiveness of a slow-release fertilizer (Customblen, Sierra Chemicals) following a pipeline 

leak of No.2 fuel oil on a beach at the Prall’s Island bird sanctuary in January 1990. The slowrelease fertilizer was placed in two shallow trenches about 4 to 6 inches bellow the surface in the 

intertidal zone. A no-treatment control plot was set up next to the treated zone. According to 

Hoff (1991), the results were inconclusive, in part due to the high variability in the TPH levels 
25 

within the treated and control areas and the lack of replicated plots. Hoff also suggested that 

either cross contamination of nutrients might have occurred between the two treatment zones or 

high background nutrient levels might have masked effects of nutrient addition. The ammonium 

concentration in the interstitial pore water at the control plot was about 1 mg/L, which is close to 

the minimum nitrogen level in pore water that would permit close to maximum hydrocarbon 

biodegradation (Venosa et al., 1996). It should also be noted that in a company report, prepared 

by Exxon Research & Engineering Company and DuPont Environmental Remediation Services 

(Madden et al., 1991), a different conclusion was reached based on the same experimental data. 

The company report indicated that “fertilizer addition clearly accelerated the rate of 

biodegradation”, although it admitted that the controls were not sufficient to provide a clear sideby-side comparison between treated and untreated zones. The conclusion was based mainly on 

the marked decrease in average TPH within the treated plots three weeks after the nutrient 

amendment. Unfortunately, neither of these two reports provided any statistical analysis in 

regard to the experimental data to support their conclusions. Of course, statistical analysis would 

have been impossible anyway since neither the control plots nor the treated plots were replicated 

and randomly situated in the intertidal zone. Again, this controversy demonstrates the importance 

of proper experimental design and data interpretation in bioremediation evaluation. For a 

detailed description of proper protocol for oil bioremediation field studies and evaluation, 

readers may refer to EPA’s Guidelines for the Bioremediation of Marine Shorelines and 

Freshwater Wetlands (Zhu et al., 2001). 

In a manual on treating oil spills in tundra environments published by Alaska Department 

of Environmental Conservation, Athey et al. (2001) compiled dozens of case studies on the 

experience of oil spill cleanup in Alaska. Among these cases, five involved the use of 

bioremedial approaches, mostly biostimulation with agricultural fertilizers. The results showed 

that nutrient amendments have generally been successful in reducing hydrocarbon levels in the 

tundra soil. For example, in August 1989, a crude oil spill from a leaking valve on a production 

line occurred in the North Slope oilfields. After pooled oil was vacuumed, fertilizers (8-32-16 at 

215 lbs/acre and 34-0-0 at 185 lbs/acre) were applied during spring/summer of 1990 and 1991, 

respectively. Following the nutrient treatment, the mean soil TPH concentration decreased 92% 

by 1993 and 96% by 1996. Similar results were obtained in two other cases that used the same 

fertilizers. In another case, a field trial was carried out to evaluate different revegetation methods 

following a crude oil spill from a check valve station near Prudhoe Bay. Five treatments were 

established: 1) cover with clean material, 2) remove contaminated material and replace with 

clean material, 3) till with a concrete rake, and 4) apply an unidentified oil degrading bacterial 

product, 5) no treatment. These plots were then seeded with vegetation and fertilized with a 14-

30-14 agricultural fertilizer. The study found that the most effective treatment in terms of both 

oil degradation and grass yield was the combination of tilling and fertilization. The result also 

suggested that biostimulation with nutrient addition alone was more effective than microbial 

seeding in this arctic tundra environment. 

3.2 Vendor’s Reports 

To better understand the scope and potential of the use of bioremediation products, 

efforts were made to collect information from vendors of bioremediation agents and their service 

providers. A summary of the results of this information collection and a comprehensive review 

of these non-peer reviewed articles are presented in this section. 
26 

3.2.1 Information collection 

In February 2002, 70 vendors of bioremediation agents that are listed either on the NCP 

Schedule or on 20th International Oil Spill Control Directory (Oil Spill Intelligence Report, 

2000) were contacted through emails or letters in regard to their interest in participating in our 

case study review (see Appendix A, Initial Letter Calling for Information). A follow-up letter 

listing the detailed information requested was then issued to each company that positively 

responded to our initial letter (see Appendix B, Follow-Up Letter to Participating Companies). A 

total of eight vendors of bioremediation products were willing to participate in this investigation 

and submitted at least some the information requested. The name, major bioremediation 

products, and contact information of these participating companies are listed in Table 3.1. 
27 

Table 3.1 List of Companies That Participated in This Review

Manufacture or Vendor Bioremediation Product(s) Contact Information 

Enviro-Zyme, Inc. BR, formerly 

ENVIROZYME BR 

P.O. Box 169 

Stormville, NY 12582

Tel: 1-800-882-9904

info@envirozyme.com

P.O. Box 3652 

Forrester Environmental Vero Beach, FL 32964 

Technologies Corp. (FET BioCATalystIOS-500 1-407-758-9033

Group) envirotec@earthlink.net 

Garner Environmental Services, 

Inc. Petro-Clean 

1717 West 13th Street

Deer Park, TX 77536 

1-800-424-1716

wsbiosolve@aol.com

P.O.Box 157 

Sebastopol, CA 95473 

Industrial Wastewater Solution IOS-500 1-707-824-1282

IWS@sonic.net

Medina Agriculture 

Products Co., Inc. 

Medina Microbial Activator

Bio-D Nutrients 

Hydrocarbon D-Grader 

P.O. Box 309 

Hondo, TX 78861

1-830-426-3011

medina@medinaag.com

Petrol Rem, Inc. PRP (Petroleum Remediation Product)

(a/k/a WAPED) 

2275 Swallow Hill Road

Bldg 2500

Pittsburgh, PA 15220

1-800-246-2275

info@petrolrem.com

7309 Schneider

Houston, TX 77093-8501 

Verde Environmental, Inc. Micro-Blaze 1-800-626-6598

bscogin@micro-blaze.com

4901 Milwee Suite 109

Houston, TX 77092

WMI International, Inc. WMI-2000 1-800-460-45074 

wmi@wt.net 
28 

3.2.2 Summary of case studies submitted by vendors 

A complete list of materials submitted by the eight vendors is shown in Table 3.2. A 

brief description of their major bioremediation product(s) and a summary of selected case studies 

for each company are presented here, following the alphabetical order of the companies’ names. 

It should be noted that these cases do not necessarily reflect all cleanup efforts of each company. 

They are selected based on relevancy to the scope of this report, sufficient information provided, 

and scientific merit. 

3.2.2.1 Enviro-Zyme, Inc. 

Product(s)

BR (formerly ENVIRO-ZYME BR) is the major oil bioremediation product 

manufactured by Enviro-Zyme, Inc. This product was listed on the NCP Product Schedule as a 

biological addictive when this report was written. According to the company, “BR” contains 

sufficient types of microorganisms enriched to degrade oil, aliphatic, and aromatic chemical 

pollution in soil and aqueous environments. BR also contains nutrient additives and a surfactant. 

It is a dry solid product with a shelf life of 1 year. BR should be mixed with water and applied 

through a low-pressure spray nozzle. 

Case studies

Information on several pilot-scale and full-scale applications of BR was provided by the 

company for each case, which included the use of BR to treat wastewater containing oil and 

grease in two full-scale cases and to treat a BTEX-contaminated soil in one pilot study. A 

summary of these relevant case studies is described as follows. 

• Bioremediation of BTEX: A pilot test was conducted in central Florida to evaluate the 

effectiveness of BR in treating a surface soil contaminated by a hydrocarbon waste from a 

dye manufacturer. The primary contaminants in this waste were benzene, toluene, 

ethylbenzene, and xylene (BTEX). The results showed that 7 months after the application 

of BR, the removal efficiencies for the benzene, ethylbenzene and toluene were essentially 

100%, while the xylene reached 88% removal. No control was reported in this study. 

• Bioaugmentation treatment of oil and grease: A wastewater from a bus installation in 

Washington D.C. contained high levels of grease and oil. The average concentration of 

grease and oil in the waste holding tank was 21,800 mg/L, which was an unacceptable 

discharge to the municipal sewage system. BR was then added daily to the grease and oil 

holding tank in conjunction with aeration. After six weeks of the treatment, the grease and 

oil level decreased to an average of 1,200 mg/L. Similarly, BR was also used to assist in 

treating a wastewater containing oil and grease from a New York railroad yard. The 

industrial wastewater was normally treated in an aeration lagoon. However, during the 

winter season, treatment efficiency declined, and the lagoon could no longer meet the State 

Pollution Discharge Elimination System (SPDES) Permit limits. The wastewater used to 

be bypassed to a holding basin until spring. However, with the addition of BR to the 

influent of the aeration lagoon at a rate of 2 pounds per day during the winter season, the 
29 

effluent has successfully met the SPDES permits for BOD, TSS, and grease & oil, and has 

been allowed to discharge into the Hudson River all year-round. 

3.2.2.2 Forrester Environmental Technologies Corp. (FET Group) 

Product(s)

BioCATalyst (a.k.a. Sheen Solution, Bio Cat 2001, BIOCAT VFB) is a bioremediation 

product custom manufactured for FET Group by Biocat VFB Solutions Company, Inc., Toccoa, 

GA. This product is a kelp extract modified by a surface-active agent and other natural materials. 

The main active ingredient is a cytokinin extract, which is a plant hormone known to be a plant 

growth enhancer. 

According to a FET Group’s technical bulletin, BioCATalyst “works in two ways on oil 

spills”: dispersion and biostimulation. The product contains a natural plant surfactant and 

emulsifier, which acts to break up oil into droplets, suspending the droplets into the water 

column. Indigenous bacteria are claimed to be biostimulated by the cytokinin such that their 

metabolic processes are greatly enhanced, resulting in much quicker biodegradation of 

substrates. BioCATalyst is normally applied as a fine spray. It is also recommended to be mixed 

on site with nutrient solutions supplied by the manufacturer. 

Case studies

Chemical analysis reports on two full-scale applications of BioCATalyst were provided 

by FET Group, which involved treating petroleum hydrocarbon contaminated water in Florida. 

One of the reports came with a one-page case description, which is summarized as follows. 

• At an orange grove in central Florida, a leak of fuel tanks used for orange blossom heaters 

led to heavy soil contamination by diesel and gasoline. After the removal of the 

contaminated soil, groundwater flowed into the excavation and also became contaminated 

with petroleum hydrocarbons. The 163,000 gallons of water was first treated with the 

chemical oxidant potassium permanganate. However, this approach was unable to meet the 

Florida DEP requirements. BioCATalyst was then applied at a rate of approximately 10 

gallons per day over a period of 14 days. The analysis results (EPA method 610/8100) 

showed that hydrocarbon concentrations decreased dramatically after the treatment, and 

the site was able to meet the required State levels. For example, the concentrations for 

benzene, xylene, and naphthalene were reduced from 42, 335, and 22 μg/L to 1, 1 and 5 

μg/L , respectively, in 14 days. Similar results were obtained using BioCATalyst for the 

treatment of another open pit of contaminated aquifer water in a second analytical report. 

3.2.2.3 Garner Environmental Services, Inc. 

Product(s)

Garner Environmental Services, Inc. is a primary distributor of “Petro-Clean”, a product 

manufactured by Alabaster Environmental Corp., Pasadena, TX. According to the product 

catalog, Petro-Clean contains surfactant, nutrients, and hydrocarbon degrading bacteria. This 
30 

product is currently listed on the NCP Product Schedule as a surface-washing agent based on one 

of its main active ingredients – a surfactant. On the other hand, it is also marketed as a 

bioremediation agent by vendors since it also contains active microbes (estimated by the 

manufacturer at approximately 50 billion per gallon). The main microbial species are naturally 

occurring Bacillus spores. Petro-Clean is normally applied through power washers or even 

garden type sprayers in diluted solution. More information in regard to this product can be found 

on the web site of EPA Oil Spill Program (http://www.epa.gov/oilspill). 

Case studies

The manufacturer provided information on four full-scale applications of Petro-Clean. 

Three of these cases involved the cleanup of petroleum hydrocarbon contaminated soil, and the 

other concerned the treatment of creosote-contaminated soil. TPH or creosote concentrations 

before and after Petro-Clean treatments were provided for all the cases, which showed apparent 

reduction of the contamination levels after the treatments. One of the case studies that involved 

the cleanup of petroleum hydrocarbons and included a detailed sampling layout is summarized as 

follows. 

• Bioremediation of a Petroleum Compressor Station: A severe petroleum hydrocarbon spill 

occurred due to a leak from three compressor units. The soil/gravel site was approximately 

six acres with heavy contamination on three acres. The bioremediation treatment involved 

the following techniques: 1) wet vacuum removal of surface liquid contamination; 2) 

surface cleaning with Petro-Clean; 3) subsurface injection with Petro-Clean; and 4) tilling 

in absorbents with Petro-Clean. Three sampling locations that covered various 

contamination levels were set up to monitor the performance of the treatment. Before the 

bioremediation operation, TPH concentrations for the three sampling sites were 11,000, 

147, 000, and 130,000 mg/L, respectively. The results showed that within 2 to 6 weeks 

after the treatment, the levels at all three sites were reduced to a permitted TPH level, 

which was less than 10,000 mg/L. 

3.2.2.4 Industrial Wastewater Solutions Corp. 

Product(s)

Industrial Wastewater Solutions Corp. (ISW) is a corporate spinoff from International Organic 

Solutions (IOS), which is the manufacturer of a microbial product, called IOS-500 (US Patent 

#5.531.898). According to materials provided by ISW, which consults for IOS on 

bioremediation projects, IOS-500 is a blend of facultative bacterial species that use organic 

compounds as a primary food source and is effective in both aerobic and anaerobic 

environments. Based on the patent description (Wickham, 1995), IOS-500 also contains an 

enzyme mixture and an organic nutrient source. This product has been used for treatment of 

contaminated soils, remediation of contaminated bodies of water, and in agricultural, industrial 

and domestic wastewater treatment systems. The product is normally mixed with water for 

about 6 to 48 hours at ambient temperature to produce an acclimated mixture, and then applied to 

the contaminated environment. 
31 

Case studies

The manufacturer provided a table that lists 28 remediation cases using IOS-500 for 

treating hydrocarbon-contaminated soils. The information in the table includes clients’ names 

and/or locations, types of oil/hydrocarbons, duration of the treatment, amount of the 

contamination, and the TPH levels before and after treatment. The package submitted by IWS 

also contained more detailed information on three cases that were conducted in Mexico for oilspill cleanup using IOS-500, which included a one-page description for each case, pictures from 

the field, and letters of acceptance/acknowledgement from the customers. A brief summary of 

these three cases is presented as follows: 

• Case #1: This case study was a demonstration at the request of a State-owned Oil 

Company in Mexico to prove the ability of the IOS product and process to provide rapid 

degradation of heavily contaminated areas. The project involved the remediation of 25 

cubic yards of 50-year-old weathered crude oil in mud and soil. After 21 days of IOS-500 

treatment, the TPH level was reduced by 89%, although no concentration data and 

sampling plan were described. 

• Case #2: IOS-500 was used to cleanup 5,000 yd3 of wetland soils contaminated by a 50-

year-old spill of crude oil and tar. The contaminated soil was first excavated from the 

wetland and then mixed with IOS-500 using small front-end loaders, a water pump, and 

hoses. The TPH concentration for the untreated soil was 436,000 ppm on average (number 

of samples and replication unknown). After 42 days of treatment, the soil TPH level was 

reduced to 4500 ppm. 

• Cases #3: This case study involved the remediation of 10,000 yd3 clay, sand and mud type 

soil contminated by a fuel oil. Using similar land treatment procedure as in Case #2, TPH 

concentrations were reported to decrease from 80,000 to 452 ppm within 60 days. It was 

also noted that this job was completed during the rainy season. 

3.2.2.5 Medina Agriculture Products Co., Inc. 

Product(s)

Medina bioremediation products include Medina Microbial Activator or Soil Activator, 

several nutrient formulations and microbial blends. Medina Microbial Activator is a liquid 

formulation derived from a controlled fermentation process and contains compounds that 

stimulate microbial activities. Nutrient products include NP-1000 and MS100-plus-NP for water 

phase bioremediation, and Bio-D for soil remediation. Bio-D is a liquid product containing 

organic humic substances, as well as inorganic nitrogen, phosphorus and potassium. Microbial 

products include a granular formulation (Hydrocarbon D-Grader) and a liquid formulation 

(HCD). Medina also offers a “Spill Response and Bioremediation Kit”, which includes Medina 

Microbial Activator, Bio-D nutrients, Bio-C organic solvent, Hydrocarbon D-Grader, Petrosorb, 

plastic bags and sheet, and manual. 

A general procedure (material concentrations unspecified or not reported) for using the 

kit to treat oil-contaminated soil was provided, which includes: 1) spray Bio-C solvent on the 
32 

affected area if the spill is old; 2) till the soil to the depth of the oil penetration; 3) mix 

Hydrocarbon-D-Grader with water and spray over affected area, 4) mix Medina Microbial 

Activator and Bio-D together with water, spray over affected area, tilling the treated area, 5) add 

water on a weekly basis to keep treated area moist. 

Case studies

Information on several pilot and full-scale applications of Medina bioremediation 

products was provided, which include two journal articles (Shafer 1991&1992) and three 

“Bioremediation Reports” (a two-page company fact-sheet) on the performance of Medina Soil 

Activator, and an abstract of a company report on a soil bioremediation project using an organic 

nutrient product. A summary of these case studies is described as follows. 

• Pilot study on effectiveness of Medina Soil Activator: In October and November 1989, a 

seven week pilot study was carried out by Woodward-Clyde Consultants (Denver, CO) on 

a site in Oakland, CA to evaluate the effectiveness of three bioremediation methods for 

treating an oil contaminated soil. The three treatments included the addition of 1) Medina 

Soil Activator, 2) an emulsifier plus a multiple-nutrient fertilizer, and 3) an emulsifier, a 

fertilizer, and proprietary hydrocarbon-degrading microorganisms. The contaminated 

material was placed in three wooden frame plots (6.5 cubic yards per pile) for testing the 

three treatments respectively. No untreated-control was set aside in this study nor were any 

replicate plots set up. After the applications of these bioremediation products, each plot 

was tilled three times for the first four weeks. Two composited samples were taken from 

each plot for TPH analysis at 2nd, 4th, and 7th weeks after the treatment. The results showed 

that all three treatment methods were able to reduce TPH concentrations from 605 mg/kg 

on average to at or below 200 mg/kg level. The Medina Soil Activator plot achieved the 

highest hydrocarbon removal with an average TPH concentration of 145 mg/kg by week 7. 

Because Medina Soil Activator was also the least expensive product, it was proposed as 

the choice of the treatment for the cleanup of this site. 

• Bioremediation of diesel contaminated soil and tundra: In the early 1980s, a diesel fuel 

pipeline ruptured at a U.S. Air Force station in arctic Alaska. During the summers of 1989 

and 1990, two bioremediation approaches were applied by Woodward-Clyde Consultants 

using Medina Microbial/Soil Activator to remediate the contamination. The first approach 

was to clean up the contaminated soil using a land treatment unit (LTU). The dieselcontaminated soil was excavated and moved to a nearby LTU. The average initial TPH 

concentration was 11,500 mg/kg (number of sample replicates unknown). A surfactant 

solution was first applied to the soil to make the oil more available. Then a diluted Medina 

soil activator was applied once every two weeks. The soil was also turned once a week to 

aerate the LTU. At the end of the six-week period, TPH in the soil was reduced by 42 

percent. The treatment was resumed in the summer of 1990. The land treatment process 

achieved 75% TPH removal during these two treatment periods. To reduce the disturbance 

to natural vegetation in the arctic tundra, an in-situ treatment approach was also tested 

during the same period, which involved surface-spraying a surfactant and Medina soil 

activator. Overall TPH levels were reduced from an average of 19,000 mg/kg to 8,300 

mg/kg (57% removal) based on analytical results of four composite samples from 

randomly selected locations in the affected area. 
33 

• Soil bioremediation using an organic nutrient product: Approximately 100 cubic yards of 

diesel-contaminated soil was treated using a Medina organic nutrient product in a CocaCola distribution facility in California. The contaminated soil was treated with this 

unspecified Medina nutrient product five times between November 2, 1990 and April 23, 

1991 in a land treatment unit. TPH concentrations were reduced from an average of 240 

ppm to less than 10 ppm (EPA method 418.1). 

3.2.2.6 Petrol Rem, Inc. 

Product(s)

Petrol Rem is the manufacturer of PRP (a/k/a WAPED), a bioremediation product listed 

as an Enzyme Additive on the current NCP Product Schedule. According to materials submitted 

by Petrol Rem, PRP consists of tiny spheres of treated wax, which contain nutrients. As 

mentioned earlier in Chapter 2, PRP also contains nonpathogenic bacteria within wax particles 

although they are mostly not oil degraders (Lee et al, 1997; NETAC, 1993b). When PRP is 

sprayed as a loose powder, it can absorb twice its weight of oil and form a physical matrix that 

floats on water, thereby preventing the pollutants from sinking and limiting the transport of oils 

to more sensitive areas. The matrix then provides an environment that uses naturally occurring 

microorganisms in the water to degrade the pollutant as well as PRP itself. The mechanisms of 

enhancing oil biodegradation for this product, however, are still not well understood (NETAC, 

1993b). 

PRP is available in three forms: 1) powder form for treating open water spills, 2) 

BioBoom for oil spills that require containment, and 3) BioSok for treating spills in enclosed 

areas such as boat bilges. 

Case studies

Information on several pilot and full-scale applications of PRP products was provided, 

including a 50-page report from the National Environmental Technology Applications Center 

(NETAC, 1993b) on the effectiveness of PRP in a mesocosm field study, a report from GMS 

Technologies (1999) on the evaluation of the BioSok product in a microcosm study, and 

company reports of two field trials. A summary of these case studies is described as follows. 

• Bioremediation Product Evaluation: Mesocosm Field Study PRP Formulation #1 (NETAC, 

1993b): A 21-day mesocosm study was conducted in a Petrol Rem testing facility to 

evaluate the performance a PRP product. Three treatments were tested in three equal size 

tanks (10 x 3 x 4 ft3

), where a gallon of fresh diesel fuel was added to each tank, and water 

from a natural source was pumped through continuously to simulate a flowing fresh water 

stream. The three treatments were 1) absorbent control (two one-pound sleeves of 

polypropylene absorbent), 2) no treatment control, 3) BioBoom + BioSok + PRP powder. 

GC/MS was used for hydrocarbon analysis, and the ratio of C17/pristane used as the 

measure of biodegradation effectiveness. The study concluded that PRP significantly 

stimulated the degradation of the hydrocarbon slick as compared to the absorbent and no 

treatment controls. Evidence of biodegradation was observed based on the slight decrease 

in C17/pristine ratio in the PRP tank. However, the report also pointed out that the PRP 
34 

mode of action for the enhanced biodegradation (whether due to the added nutrients or 

beeswax material) was still unclear. One deficiency of this study was the lack of treatment 

replicates (only three tanks were used to test the three treatments). An inspection of the 

GC/MS data shown in the report revealed that the disappearance of all hydrocarbons 

appeared to take place at the same rate, suggesting that biodegradation may not have been 

the primary cause for the disappearance of the hydrocarbons. Support for this conclusion 

comes from a 3-D histogram of the data, from which it was very difficult to read 

concentrations. 

• Evaluation of the BioSok product for boat bilge treatment: This study was conducted to 

test the effect of three treatments (untreated control, mini-BioSok with encapsulated oildegrading Bacillus sp., and mini-BioSok without addition of bacteria) on remediation of 

bilge water using diesel fuel and bench-scale Bilge Model Reactors. Although this study 

was not conducted under field conditions, it is mentioned here because the test did help to 

understand the role of microorganisms in PRP. The results showed that the overall oil 

removal efficiencies were 71%, 84%, and 77% on average in four weeks for the cases of 

natural biodegradation, PRP without microbes, and PRP with encapsulation of microbes, 

respectively. A statistical analysis (Student’s T-test) indicated that there was a significant 

difference between both PRP formulations and the no treatment control (p < 0.10), but no 

significant difference between the two PRP formulations (p > 0.10). However, since the 

treatments were not replicated, the statistical analysis was flawed since such an analysis 

requires replicate treatment units in order to calculate experimental error. Even if the 

results were statistically significant, the question remains if the incremental 13% benefit 

from using PRP justifies the cost of treatment compared to natural attenuation. The study 

further demonstrated that PRP relied on indigenous bacteria, not encapsulated ones, to 

perform the oil biodegradation. 

• Field applications of PRP: Petrol Rem provided two real-world case studies. In both cases, 

only visual observation was used to monitor the performance of PRP treatment. In one case 

study, a barge carrying 4,000 metric tons of fuel oil sank in January 1998, resulting in 

fouling beaches and a mangrove along the Persian Gulf in Abu Dhabi. PRP was tested on 

site and visual observations (10 pictures enclosed in the report) found that the treated 

sections of the contaminated beach and mangrove showed marked improvement compared 

to untreated areas. Another case involved heavy oil spilled into a lagoon in Mexico in 

1994. PRP was used to treat the water surface and the shore. After 26 days, it was 

estimated that approximately 75% of the original oil had been degraded based on visual 

examination of oil coverage on the lagoon surface (6 pictures enclosed in the report). 

However, use of visual observations with no attendant chemical analysis is not a reliable or 

scientifically sound method of assessing the treatability of a site by any technology. 

3.2.2.7 Verde Environmental, Inc. 

Product(s)

Verde Environmental, Inc. is the manufacturer of Micro-Blaze, another oil 

bioremediation product listed on the NCP Product Schedule. Micro-Blaze is a liquid formulation 

of several microbial strains (Bacillus spores), surfactants, and nutrients designed to metabolize 
35 

organics and hydrocarbons in soil and water (http://www.epa.gov/oilspill). Its commercial name 

is also called Micro-Blaze Emergency Liquid Spill Control. When in use, Micro-Blaze should be 

diluted with water to a certain percentage as determined by the type of contamination and 

applied through normal spray devices. 

Case studies

Information on over a dozen full-scale applications of Micro-Blaze was provided in the 

Handbook for Suggested Uses and Applications of Micro-Blaze Emergency Liquid Spill Control, 

with one to a few pages of description for each case. The applications include hydrocarbon spill 

control, remediation of leaking underground petroleum storage tanks, wastewater treatment, and 

cleanup of firefighting training fields and food preparation sites. Two case studies that are 

relevant to this document are summarized as follows. 

• Spill responses in a refinery plant: One anonymous major refinery plant frequently uses 

Micro-Blaze to cleanup its petroleum spills. For example, Micro-Blaze was used to 

remediate a crude oil spill in a tank-field in June 1997. TPH levels dropped from the low 

thousands to low hundreds of mg/kg in approximately eight weeks. In another case, a 

diesel spill in a pipe conduit occurred in November 1997. After the free product was 

pumped out, Micro-Blaze was used to finish the cleanup. In approximately four weeks, 

TPH concentrations dropped from a range of 25,000 - 57,000 mg/kg to a range of 600 - 

9,900 mg/kg. Again, no controls were reported nor were treatments replicated. 

• Gasoline spill clean up: A major gasoline spill (approximate 6000 gals) occurred in 

Conroe, Texas, on January 27, 1994, resulting in the contamination of the city sewage 

system. The wastewater treatment plant was shut down in the early morning and the 

gasoline-contaminated wastewater was diverted to a holding pond. Micro-Blaze 

Emergency Liquid Spill Control was sprayed to the basins and the lagoon in the 

wastewater treatment plant. Within ten minutes, the fumes disappeared. The wastewater 

treatment plant was able to operate at half capacity in the early afternoon and went back to 

normal by midnight. No analytical data, however, were presented in this case to 

demonstrate the effectiveness of Micro-Blaze as well as to explain the mode of action for 

this product. It is known that bioremediation is too slow acting to account for such a quick 

a hydrocarbon spill. It is likely that, since the spill was gasoline, most if not all of the 

treatment occurred as a result of volatilization. 

3.2.2.8 WMI International, Inc. 

Product(s)

WMI International’s major oil bioremediation product is WMI-2000. This product is also 

listed on the NCP Product Schedule as a microbial additive. WMI-2000 is a dry power that 

contains microbial cultures specifically selected for remediation of petroleum products and other 

contaminants. The product may be applied as a dry powder or activated in water for 2 hours and 

applied to the surface of oil spills in water, pits, or ponds. It is also recommended by the 

manufacturer to apply nutrients with WMI-2000 microbes and maintain nitrogen and phosphorus 

concentrations in the treated water at 5-20 mg/L and 1-5 mg/L, respectively. 
36 

Case studies

Information on several pilot and full-scale applications of WMI-2000 was provided, 

which includes brief descriptions of three case studies and a company report with detailed 

analytical results on bioremediation of bilge water. A summary of two of these case studies is 

described as follows. 

• Treatment of a hydrocarbon-contaminated storm water storage pond: WMI-2000 was used 

to clean up a hydrocarbon contaminated storm water storage pond for a major U.S. 

railroad. The pond was aerated with WMI Fine Bubble Diffusers and inoculated with 

WMI-2000 microbes. Visual observation was used to monitor the treatment performance. 

The results were illustrated using a series of pictures, which showed the reduction of oil 

coverage and the improvement of water clarity from Day 1 through Day 7 of the treatment. 

Again, since this study relied on visual observations for measurement of effectiveness, 

results must be discounted. 

• Bioremediation of hydrocarbon contaminated water in ballast and bilge tanks: MWI-2000 

was used to treat the ballast tank of a ship that was contaminated with coatings of heavy 

hydrocarbons, especially on the interior walls. During the first week of the treatment, 36 

lbs. of WMI-2000 and 100 lbs of commercial fertilizer (12-24-0) were added in the ballast 

tank with a capacity of 179,000 gallons. Another 8 lbs of WMI-2000 each week was 

applied between the 2nd and 4th weeks. Forced air aeration of the bilge water was also 

applied continuously as part of the treatment. Analytical results using GC-FID showed that 

during the six weeks of the treatment, the concentrations of the various hydrocarbons were 

reduced from a range of 0.2- 4.3 mg/L to ND or 0.2 mg/L (detection limit), although no 

data was reported about the oil adhered to the interior walls of the vessel. 


37 



Table 3.2 Summary of materials submitted by participating companies 

Manufacturer

or Vendor 

List of submitted material 

Enviro-Zyme, 

Inc. • Product line cards: description, direction and MSDS about all EnviroZyme Products (BR, C, COMP, DOC, EZ, GT, L, LGD, M, N, O, P, 

POUCH, R, SEP, T) 

 A copy of “BR Composite” that includes: 

 Detail information about BR (primary ingredients, pH range, nutrient 

requirement, etc.) 

 General considerations and summaries of application for the use of 

bioaugmentation products for assisting the cleanup of oil spills or soil 

contamination. 

 Brief description of four case studies on the use of BR 

 A journal paper promoting the use of bioaugmentation: Jensen, R.A. 

(1996) Bioremediation using bioaugmentation, Environmental 

Technology, 11/12, 1996 

Forrester 

Environmental

Technologies

• Information about BioCATalyst --a biostimulation product from botanical 

extraction. 

Corp. (FET 

Group)  FET Group technical bulletins about BioCATalyst 

 BOD5 test results from BSC (Biocatalyst Solution Company) 

 MSDS 

 Letter of acceptance from The Bureau of Petroleum Storage System, 

Department of Environmental Protection, Florida, for injection type of 

aquifer remediation 

 Brief description of two case studies on the use of BioCATalyst with the 

attachment of hydrocarbon analysis reports 

Garner

Environmental • A catalog on Petro-Clean microbial products that includes: 

Service, Inc.  Petro-Clean products facts 

 Brief description of four case studies 

 Direction for use of Petro-Clean 
38 

 MSDS 

Industrial 

Wastewater • A detailed letter of qualifications through email, which describes: 

Solutions Corp.  Company background and its product IOS-500 

 A list of field applications and treatment results

 Areas of applications 

• A CD-ROM containing further information about IOS-500: 

 Introduction of IOS-500 

 Brief descriptions of three case studies 

 Letters of acceptance/acknowledgement from customers 

 Pictures from the field 

 Letter of recognition of non-pathogenicity for IOS-500 from Health 

Care Service of Alameda County, CA 

Medina 

Agriculture 

Products Co., 

Inc.

•

•

Brochures regarding Bioremediation Division of the company, its 

products and services. 

A more detailed Medina Bioremediation Catalog, which includes: 

 Procedure for using bioremediation products and an example of a land 

farming project 

 Bioremediation compatibility testing

 Product guide 

 List of support service and price quotes 

 Domestic customer list 

 MSDS 

• Summaries of three case studies on the effects of Medina Soil Activator 

• Detailed abstracts of two company reports on a lab treatability study and a 

field trial on Medina bioremediation products. 

• Two technical journal articles that involved the use of Medina 

bioremediation products: 
39 

 Shafer, R. (1992). “Bioremediation of a California Land Site: a costeffective way to treat oil contamination.” Our California Environment, 

winter 1992. 

 Shafer, R. (1991). “Cleanup old problems: Bioremediation of diesel 

contaminated soil and tundra.” Land and Water, Nov/Dec, 1991 

PetrolRem, Inc • A PRP portfolio, including a PRP Bioboom-Biosock Product Video CD 

• Reports on PRP from governmental agencies and Petrol Rem’s partners 

 Review worksheet on PRP by U.S. Coast Guard’s Alternate Response 

Tool Evaluation System (ARTES) program 

 National Environmental Technology Applications Corporation 

(NETAC) (1993b). “Bioremediation Product Evaluation: Mesocosm

Field Study PRP Formulation #1.” 

 GMS Report (1999). “Evaluation of the BioSok® product for boat bilge 

treatment and the reduction of non-point pollution,” a research report by 

GMS Technologies to USEPA under EPA contract No. 68-D-98-138 

 Larry Lawson (1999). Excerpt from the Report to GMS Technologies on 

Commercialization Assessment of Improved Bio-Sok by Foresight 

Science & Technology under contract to the EPA 

• Company reports on two case studies 

 Mexico field study results 

 Abu Dhabi field test results with a letter of recognition by the customer 

Verde 

Environmental, • Three introduction and training videos 

Inc.  Micro-Blaze microbial products for use in wastewater/septic systems 

 Micro-Blaze emergency liquid spill control (training video) 

 Micro-Blaze Out Microbial fire fighting agent (training video) 

• Handbook for suggested uses and applications, which include several 

documents and case histories, as well as regulatory agency acceptance 

letters 

• Acceptance letters from the states of Florida and Ohio that have been 

received since the manual was put together 

• A manual of technical papers, which include bioremediation background 
40 

information and several biodegradability studies 

• A manual of toxicity, bioremediation tests, and chemical analysis, all of 

which was required by the EPA for Micro-Blaze to be placed on the EPA 

NCP product Schedule as a bioremediation agent 

• Various promotional flyers. 

WMI 

International, 

Inc.

• Summary of three case studies on the effects of WMI-2000 microbial 

products 

• A company report: Bio-Remediation of Hydrocarbon Contaminated water 

in Ballast and Bilge Tanks, which include 

 Treatment schedule in ballast tanks 

 Hydrocarbon analysis report 

 MSDS of WMI-2000 

 Toxicity test of WMI-2000 

 Letters from EPA and Department of Health & Human Services 

3.2.3 Review of vendor reports 

As shown in the previous section, the amount and quality of the submitted information 

was highly variable. Case study information mostly ranged from a few sentences to one to two 

pages, although there were also a few detailed technical reports of up to 50 pages. It is 

impossible to give a comprehensive review of each case based on this limited information. 

Therefore, a summary of important findings and general critique on the technical merit of all 

these reports are presented here. 

• Bioremediation products have been applied to clean up petroleum hydrocarbon 

contamination in various ecosystems and under a wide range of environmental conditions. 

Their applications include in-situ remediation of hydrocarbon contaminated marine 

shorelines, soil environments, surface water, groundwater, and bilge water, and ex-situ

treatment of hydrocarbon contaminated soil (e.g., using a land treatment unit) and water 

(e.g., in a bioreactor). However, most of these cases involved treating relatively small-scale 

petroleum hydrocarbon contamination in somewhat confined environments (e.g., lagoons, 

land treatment units, ships, etc). The bioremediation applications were used as either a 

primary response strategy or a secondary polishing step after conventional mechanical 

cleanup options had been applied to remove free oil products. Oil and hydrocarbon 

contamination were observed to be reduced based on TPH analysis and visual 

observations. The submitted materials seem to suggest that these bioremediation products 
have satisfied many customers and have been able to meet regulatory requirements for 

their clients. 

• A major limitation of these vendor case studies is that due to the confounding of different 

effects, it is impossible to determine whether the claimed enhanced oil biodegradation, if 

true, resulted mainly from the addition of microbial cultures, nutrients, enzymes, oxygen, 

or any combination of above. Among the ten bioremediation products described in the 

vendors’ reports, six were bioaugmentation agents that contain hydrocarbon degraders (i.e., 

BR, Petro-Clean, IOS-500, Medina Hydrocarbon D-Grader, Micro-Blaze, and WMI-2000) 

and four were biostimulation agents containing either enzymes or nutrients but no active 

hydrocarbon degraders (i.e., BioCATalyst, Medina Microbial Activator, Bio-D Nutrients, 

and PRP). All of these microbial products contained nutrients and surfactants or required 

applying with nutrient products. In most of the reported field applications 

(bioaugmentation or biostimulation), certain types of oxygen amendment were used as 

well, such as tilling of contaminated soil or forced air aeration of polluted water. 

Therefore, no conclusion can be made solely based on these reports in regard to the 

determination of the limiting factors (microbes, nutrients or enzymes) for oil 

biodegradation, although in some cases there was some evidence that microbial 

amendments did not enhance oil biodegradation better than biostimulation (GMS Report, 

1999; Shafer, 1992). 

• The technical merit of these company reports was generally not sound in terms of 

providing strong or even suggesting moderate scientific evidence for demonstrating the 

effectiveness of bioremediation products. As described in Chapter 2, evidence for the 

effectiveness of oil bioremediation in terms of oil biodegradation should include: (1) faster 

disappearance of oil in treated areas than in untreated areas, and (2) a demonstration that 

biodegradation was the main reason for the increased rate of oil disappearance. To obtain 

evidence of increased rate of disappearance, a set-aside untreated area or a control should 

be used, which has similar physical and biological conditions as the treated site. However, 

no controls were used in most of the reported case studies. Although oil spill responders 

prefer not to set aside any oiled untreated sites, it is difficult to assess the true impact of a 

treatment without control or set-aside areas. To effectively distinguish biodegradation from 

abiotic loss, specific oil components or analytes should be analyzed occasionally using 

GC/MS techniques. These analytes should be normalized to a conserved biomarker, such 

as hopanes and/or alkyl-substituted chrysenes. Again, except for the report on the 

mesocosm test of PRP (NETAC, 1993b), none of these cases used GC/MS analysis. In 

most of the cases, oil/hydrocarbon concentrations were evaluated by simple TPH analysis. 

For others, visual observation was the only method of monitoring the treatment 

performance. Since all TPH techniques are severely affected by spatial heterogeneity, it is 

essential that a well-thought out sampling plan be designed according to valid statistical 

principles involving randomization and replication of treatments in order to ensure that 

monitored results reflect reality in such a highly heterogeneous environment,. 

Unfortunately, very little if any statistical analyses were conducted to support the 

conclusions and claims made by the vendors and writers of those reports. Considering 

current regulatory requirements and the cost of the hydrocarbon analysis, it may not be 

realistic for oil spill responders to conduct detailed GC/MS analyses during oil spill 

bioremediation applications (except perhaps an occasional sample). However, in order to 

41 
42 

provide more convincing evidence of product effectiveness, the oil bioremediation industry 

can and should do more to acquire the highest quality data possible within budget 

restraints, such as following sound statistical principles of experimental design and 

adopting a well-designed sampling plan. 

3.3 Bioremedial Approaches for Controlling Petroleum Hydrocarbons in Stormwater 

and Bilge Water. 

One of the objectives of this review was to evaluate and assess the use of bioremediation 

technology for the cleanup of hydrocarbon contamination from storm water discharges and boat 

bilges. After a thorough search of the literature, however, little information was available on the 

field experience pertaining to the use of bioremediation agents for treating petroleum 

hydrocarbons in stormwater and bilge water. Therefore, the potential of using bioremediation 

products in these non-point sources can only be briefly discussed as follows. 

3.3.1 Bioremediation of hydrocarbon contamination from storm water discharges 

It is estimated that about 0.12 metric tons of petroleum hydrocarbons are released into the 

world’s water through urban runoff every year, which make up approximately 4% of oil input 

into the oceans (NAS, 1985). Urban runoff is also the leading source of impairments to surveyed 

estuaries according to recent National Water Quality Inventory reports (U.S. EPA; 1996). 

Technologies that are currently used as Best Management Practices (BMPs) for 

controlling hydrocarbons in stormwater include oil and grease trap devices, wet detention ponds, 

wetland systems (phytoremediation), and filter systems (Botts et al. 1996, Shutes et al., 1997, 

Schueler, 1987, U.S. EPA, 1997). Trap devices for removing oil and grease from stormwater 

include various mechanical oil-water separators, oil and grease skimmers, and water quality 

inlets. The skimmer is often used at the outlet of a sediment basin. Water quality inlets consist of 

a series of chambers or basins that remove sediment, screen debris, and separate free oil from 

storm water. Wet detention ponds maintain a permanent pool of water in addition to temporarily 

holding stormwater, and they provide both quality and quantity control of storm water. 

Hydrocarbons in stormwater are degraded through natural attenuation. Constructed or restored 

wetlands are also effective means of controlling low-level hydrocarbon contamination, which use 

green plants and their associated rhizosphere microorganisms to degrade and contain pollutants. 

Nix et al. (1994) investigated the performance of a wetland system for treating storm runoff 

containing diesel fuel and found that 96% of the total extractable hydrocarbons were removed 

after only five hours retention. Another bioremedial technology for treating stormwater is 

compost stormwater filters (CSF). This innovative system removes contaminants from 

stormwater by allowing water to pass through layers of specially tailored compost. A CSF can 

typically remove over 90% of all solids and 85% of oil and grease (U.S. EPA, 1997). 

Although the approach of adding biostimulation and/or bioaugmentation agents has not 

been selected as BMPs for the treatment of hydrocarbon contamination in stormwater, limited 

information gathered suggests that application of bioremediation agents could be a promising 

approach, especially used in conjunction with other stormwater countermeasures, such as wet 

detention ponds. For example, BR (Enviro-Zyme, Inc) was used to assist in treating an industrial 

runoff containing oil and grease in an aeration lagoon during winter seasons, when the existing 
43 

treatment system could not meet the regulatory standard (see Section 3.2.2.1). WMI-2000 also 

treated hydrocarbon-contaminated stormwater in a wet detention pond, but this reported success 

was based on visual observation (see Section 3.2.2.8). However, further field tests are still 

required to evaluate the effectiveness of this strategy, particularly to determine whether addition 

of microbial cultures is necessary or effective in enhancing oil biodegradation in stormwater. 

3.3.2 Bioremedial approaches for treating bilge oil 

Bilge oil discharge is another major source of petroleum contamination for the world’s 

navigable waters. It is estimated that bilge oil comprises 9% of oil input into the oceans (NAS, 

1985). Currently international regulation does not allow ships to discharge bilge water containing 

more than 15 mg/L of oil. Some of the BMPs for reducing the amount of oil from boat bilges 

entering marinas and surface waters include: promoting the installation and use of fuel/air 

separators on air vents; avoiding overfilling fuel tanks, maintaining proper engine performance 

and routinely checking for fuel leaks; promoting the use of materials that capture or digest oil in 

bilge water; extracting used oil from absorption pads if possible; and prohibiting the use of 

detergents and emulsifiers on fuel spills (U.S. EPA, 2001). 

Commonly used methods for in-situ treatment of bilge water include oil water separators, 

such as centrifuges, for large vessels and absorption devices, also called “bilge socks” or “bilge 

pads”, for smaller recreational boats. Some of these products are also combined with bioremedial 

processes. For example, a “bio-mechanical” oil water separator, trademarked as PetroLiminator, 

was developed recently by Ensolve Biosystems, Inc. (Raleigh, NC). This device is a nonpressurized three-stage vessel: Stage 1 allows for initial separation of heavy or pure oil. The 

retained emulsified oil is then biodegraded in a separate biofilm reactor at Stage 2. Stage 3 

consists of a final clarifier for solids removal, and the effluent is then discharged. PetroLiminator 

has been tested in sea trials (MarineLog.com, 2001) and has been type-approved by U.S. Coast 

Guard (USCG) and the International Maritime Organization (IMO). 

Another bioremedial method for treating bilge oil is the use of absorption pads that may 

also contain bioremediation agent(s). BioSok is one such product. According to the 

manufacturer, PetrolRem, each BioSok, which measures 9 inches in length by 3 inches in 

diameter, contains eight ounces of PRP. It is purported to absorb up to one pound of contaminant 

and degrade much more oil over time. As mentioned previously, BioSok achieved about 80% 

diesel removal in a microcosm study, slightly better than the performance of natural attenuation. 

However, no scientifically verifiable field data in regard to the rate and capacity of oil 

biodegradation for this product is available. 

Considering the simplicity of use and environmental friendliness of the processes, 

products like BioSok could be a promising solution for bilge water treatment. However, this type 

of product also faces tough competition from other absorption devices. Tests conducted by 

consumer-oriented organizations often emphasize the oil absorption capacity and the firmness of 

the oil binding (Boat U.S. Foundation, 2001; Costa, 2000), which normally is not the strength of 

the bioremedial type of bilge pads. Therefore, more work needs to be done in terms of both 

market improvement and technical demonstration of these bioremedial sorbents for them to reach 

their potential in the area of bilge oil treatment. 
44 

4 Summary and Findings 

Bioremediation is a process that attempts to accelerate natural biodegradation processes. 

The success of oil spill bioremediation depends on our ability to optimize various physical, 

chemical, and biological conditions in the contaminated environment. There are two main 

approaches to oil spill bioremediation: 1) bioaugmentation, in which oil-degrading 

microorganisms are added to supplement the existing microbial population, and 2) 

biostimulation, in which the growth of indigenous oil degraders is stimulated by the addition of 

nutrients or other growth-limiting cosubstrates and/or habitat alteration. Bioremediation agents 

are also classified as bioaugmentation and biostimulation agents based on these two main 

bioremedial approaches. Since the objective of this document was to conduct a thorough 

assessment of bioremediation products by a comprehensive review of their actual use in real 

world cases, it was hoped that documented field experiences would be able to provide the more 

convincing argument for the effectiveness of bioremediation technology. Literature reviewed 

included peer-reviewed journal articles, company reports, government reports, and actual reports 

by cleanup contractors engaged in the response to spills in inland, estuarine, and marine 

environments. The key findings of this literature review are summarized bellow: 

• Bioremediation products have been applied to clean up petroleum hydrocarbon 

contamination in various ecosystems and under a wide range of environmental conditions. 

Their applications include in-situ remediation of hydrocarbon contaminated marine 

shorelines, soil environments, surface water, groundwater, and water, and ex-situ treatment 

of hydrocarbon contaminated soil (e.g., use of land treatment units or other types of reactor 

systems such as compost piles, biopiles, slurry reactors, etc.) and water (e.g., in a 

bioreactor). Bioremediation technology is typically used as a secondary polishing step after 

conventional mechanical cleanup options have been applied to remove free oil product. 

However, many case studies have demonstrated that bioremediation can also be used as a 

primary response strategy, especially for the cleanup of environmentally sensitive areas 

that are not amenable to conventional cleanup techniques and/or low-level petroleum 

hydrocarbon contamination. 

• According to the peer-reviewed literature, bioaugmentation appears to have little benefit 

for the treatment of spilled oil in an open environment. Microbial addition has not been 

shown to work better than nutrient addition alone in many field trials. However, case 

studies provided by vendors seem to suggest that application of bioaugmentation products 

could still have some potential in the treatment of specific oil components, isolated spills in 

confined areas, or certain environments where oil-degrading microorganisms are deficient. 

Unfortunately, the evidence for such a conclusion is not strong and in most cases 

scientifically deficient. 

• Biostimulation has been proven to be a promising tool to treat certain aerobic oilcontaminated marine shorelines. One of the key factors for the success of oil 

biostimulation is to maintain an optimal nutrient level in the interstitial pore water. In other 

words, background nutrient concentrations at the contaminated site should be one of the 

primary determining factors in the decision to apply nutrients, and biostimulation might 

not always be necessary if sufficient nutrients are naturally present at a spill site to supply 

non-limiting concentrations to the degrading populations. However, effects of nutrients are 
45 

also highly site-specific. For example, the availability of oxygen rather than nutrients is 

often the limiting factor in wetland environments, where addition of nutrient products has 

not been successful in enhancing oil biodegradation (although it has been successful in 

accelerating the restoration of the affected plant biomass to an abundant and rich recovery). 

• Different nutrient products have shown variable effectiveness, depending on oil properties, 

the nature of the nutrient products, and the characteristics of the contaminated 

environments. Based on limited field trials, it appears that slow-release fertilizers may be 

an excellent choice if the nutrient release rates are balanced against physical loss rates; 

water-soluble fertilizers may be more cost-effective in low-energy shorelines and finegrained sediments where water transport is limited; and oleophilic fertilizers may be more 

suitable for use on hard, rocky shorelines, although further research is still required to 

confirm this suggestion. In general, commercial oleophilic nutrient products have not 

shown clear advantages over common agricultural fertilizers in stimulating oil 

biodegradation. 

• Bioremedial approaches may have a role in treating hydrocarbon contamination for nonpoint sources. Limited available information appears to suggest that application of 

bioremediation agents could show promise for the treatment of hydrocarbon contamination 

in stormwater, especially used in conjunction with other stormwater countermeasures, such 

as wet detention ponds. Bioremediation agents may also be effective for the treatment of 

bilge water, although, due to the lack of any systematic investigation into its effectiveness, 

it is still uncertain whether this approach could compete with other existing technologies. 

Further field tests are needed to provide stronger evidence on the potential of this strategy.

• The extreme uncertainty associated with the efficacy of bioremediation agents is due in 

large part to the poorly designed field tests that have been conducted to demonstrate 

efficacy. Much of the reported literature lacked proper controls and treatment 

randomization and replication, or the data were incorrectly analyzed. If there is any hope 

for advancement of commercial bioremediation for the environments described in this 

report, especially estuaries, experiments based on sound scientific principles are needed. 

Unfortunately, resources for field-testing commercial bioremediation agents are scarce, 

and field studies are extremely expensive to carry out. That’s why it is best to rely on 

laboratory microcosm or mesocosm studies to provide needed data to support this 

technology. When spills occur and the on-scene coordinator in conjunction with the 

Regional Response Team decides to implement commercial bioremediation for cleanup, 

they should try to set aside control areas if at all possible to allow a more effective 

evaluation of treatment success. If this practice is carried out, a true advancement in 

knowledge will be possible. 

• If there is any hope for advancement of commercial bioremediation, especially estuaries, 

experiments based on sound scientific principles are needed. Unfortunately, due to the 

extreme resource intensiveness of field studies, the benefit accruing to testing one 

bioremediation agent is only applicable to the one product being tested, not to the overall 

science of bioremediation. Testing products in the field is not within the purview of the 

federal government unless such a test has the potential of advancing science in terms of 

general microbiological and engineering principles. 
46 

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Appendix A: Initial Letter Calling for Information

Dear Madam/Sir: 

I am a research associate with the University of Cincinnati’s Department of Civil and Environmental Engineering, 

working on a contract with the U.S. Environmental Protection Agency’s Office of Research and Development. I am 

conducting an in-depth literature review on the efficacy of commercial bioremediation products for cleaning up oilcontaminated environments, with special emphasis on estuaries. The objective of this project is to conduct a 

thorough assessment of the use and effectiveness of commercial bioremediation products by reviewing actual field 

cases where bioremediation has been used. 

Based on information from EPA’s Oil Program Center, the National Contingency Plan Product Schedule, and the 

Oil Spill Intelligence Report (Cutter Information Corp.), it is my understanding that your company has been 

involved in producing and marketing bioremediation products for oil spill cleanup. Since we intend to make our 

review as inclusive and fair as possible, the field experience of your company on bioremediation agents is extremely 

valuable to us. Therefore, I would like to obtain some technical information and experience in regard to your 

bioremediation product(s). The information that is of particular interest to me includes the following: 

 Principle ingredients of your bioremediation products (without your divulging 

confidential business information). 

 Technical publications regarding the effectiveness of your bioremediation products in 

actual case studies. 

 Client response and contact information. 

The purpose of this letter is to see whether your company is willing to participate in this inquiry. Please understand 

that your participation in this endeavor is strictly voluntary. If you wish to respond, please drop me a quick note via 

e-mail, and I will contact you via telephone at your convenience and will provide you more detailed information 

about my request. If you do not wish to participate, please also let me know so that I may strike you from my list. 

Due to the time constraint of this project, I would be most appreciative if you would reply within two weeks. Thank 

you for taking the time to consider this request, and I am very hopeful to receive a positive reply from you. 

Sincerely yours, 

Xueqing Zhu, Ph.D., P.E. 

Department of Civil and Environmental Engineering 

University of Cincinnati 

Cincinnati, OH 45221-0071 

Tel: 513-556-3638, Fax: 513-556-2599 

E-mail: zhuxi@email.uc.edu 
56 

Appendix B: Follow-up Letter to Participating Companies 

Dear Madam/Sir: 

Thank you for your willingness to participate in this information collection effort as a part of EPA’s investigation of 

the efficacy of bioremediation products. I am writing to you to provide more information about this project and what 

I need from you. The objective of this project is to conduct an in-depth literature review on the efficacy of 

commercial bioremediation products for cleaning up oil-contaminated environments. The scope of this review is 

limited to the use of bioremediation agents (i.e., microbial additives and nutrient additives) for cleanup of surface oil 

spill (inland, estuarine, and marine environments, but not groundwater). The performance of other oil spill control 

agents and approaches may be included only as a point of reference and comparison. The information that is of 

particular interest to me is listed as follows: 

(1) Principle ingredients of your bioremediation products. 

Without your divulging confidential business information, can you tell me whether your products include any living 

organisms (bacteria, fungi, etc.), nutrients, enzymes, exogenous hydrocarbons, sorbents, surfactants, or anything else 

that characterizes your product and its primary mechanism of action? 

(2) Efficacy for oil spill cleanup in the field. 

Do you have any technical publications, client reports, third-party reports, and/or company reports regarding the 

effectiveness of your bioremediation products in actual case studies? Information that would be most helpful 

includes: 

• Type of spilled oil and extent of contamination; 

• Effectiveness data on hydrocarbon destruction or removal; 

• Analytical methods used to support your conclusions; 

• Detailed sampling plan design; 

• Any statistical analysis done; 

• Environment in which the product was used; 

• Anything else you would deem important to my investigation. 

(3) Client contact information. 

If you don't mind, it would be most helpful if you could reveal the names, addresses, and telephone numbers or 

email addresses of your clients so that I could contact them personally to interview them for their view on how well 

bioremediation worked in their instance. 

Our final report to EPA is due in September. I would be most appreciative if you would provide the above 

information by the end of March. I will be happy to send a copy of our completed report when it is finished, peerreviewed, and cleared by the Agency, should you desire one. Thanks again for your help. If you need any additional 

information about this request, please do not hesitate to contact me. 

Sincerely yours, 

Xueqing Zhu, Ph.D., P.E. 

Department of Civil and Environmental Engineering 

University of Cincinnati 

Cincinnati, OH 45221-0071 

Tel: 513-556-3638, Fax: 513-556-2599 

E-mail: zhuxi@email.uc.edu