Scientific
Approach
The scientific approach for NABIR was developed with the assistance of a team of
scientists and engineers from the national laboratories, and input from academic
institutions and the private-sector R&D community. Three considerations guided
development of the program. First, as summarized in the previous section "Legacy
of the Cold War and DOE's Unique Set of Remediation Challenges," opportunities
for applying bioremediation at DOE sites were identified, along with some of the
unique remediation challenges faced by DOE. Second, reports from nine recent
assessments of R&D needs for bioremediation were reviewed, and subsequent
discussions were held with some of the participants (see "Bioremediation Research
Needs"). Finally, related R&D programs in DOE and other agencies were evaluated
to determine which R&D needs were not being met by the existing programs (see
"Bioremediation and Related Programs in DOE" and "Bioremediation in Other
Departments and Agencies"). NABIR is designed to fill these research gaps and
complement other ongoing programs.
KEY THEMES OF THE NABIR
PROGRAM
The scientific approach of NABIR is characterized by several key ideas which
are highlighted and discussed below.
Fundamental research is required to advance scientific understanding of
the biological, chemical, and physical processes important for natural and
accelerated bioremediation. Research is needed in many disciplines, such as
microbiology, structural and molecular biology, genomics, geochemistry, and
hydrology and transport processes. But more importantly,
interdisciplinary research involving two or more of these disciplines is
likely to achieve breakthroughs in scientific understanding. Finally,
fundamental research should be focused on the behavior of complex
systems that include mixtures of contaminants and multiple organisms,
and this research must account for the natural spatial and temporal
variability of geologic environments.
Integration of scientific ideas across disciplines is essential
for development of the knowledge needed to predict and optimize
bioremediation rates and processes. An advance in any one aspect of
bioremediation, such as development of microorganisms with enhanced
degradative capabilities, is unlikely to make an impact unless other
factors, such as how to introduce the microorganisms into the soil, are
also improved. Scientific advances in many key aspects of
bioremediation must be coordinated and integrated at every step of the
way.
Overcoming the traditional walls that inhibit integration of
disciplines is one of the keys to the success of NABIR.
Field research centers are the best vehicles for promoting and
coordinating cooperation among research teams; identifying crucial
fundamental, interdisciplinary research needs; achieving the integration
described above; and focusing the research program on DOE's most
significant problems. In addition, performing research at a contaminated
site will facilitate the two-way transfer of information needed to ensure
that the scientific results of this program will be integrated into site
remediation strategies. Other opportunities, such as co-locating a
bioremediation technology demonstration nearby, would allow for a host
of synergistic interactions between technology development and
fundamental research programs.
Access to R&D shared infrastructure will be required to
advance measurement and diagnostic techniques for understanding,
quantifying, and enhancing biotransformation processes and rates.
Examples of the facilities required could include:
In addition to instrumentation, a set of shared computational models and shared
strategies for mathematically representing and visualizing biogeochemical processes
will be required. Networks to efficiently link researchers to databases and models
will facilitate rapid transfer of knowledge among the team and to other interested
parties. One of the first tasks of the program will be to develop a set of specific
recommendations on the nature and location of scientific infrastructure needed to
support this program. Instrumentation and communication infrastructure needs will
be evaluated on an ongoing basis, and recommendations will be made for developing
new capabilities.
The goals of the research program and the interrelationships between the
goals of program elements must be clearly identified. In the following
sections, the research program is described in terms of program goals at three, five,
and ten years.
Linkages to related research and technology development programs
will be established and maintained to ensure that NABIR builds on knowledge
gained from other programs, fills in key gaps in scientific understanding, focuses on
DOE's most important environmental problems, and leverages funds and shares
resources when possible. In particular, NABIR will work closely with OEM's
Contaminant Plumes and Landfill focus teams to facilitate the seamless integration
of knowledge between these complementary programs.
These themes will be implemented through the seven program elements shown in
Fig. 3 and described below.
THE SEVEN PROGRAM ELEMENTS OF NABIR
The NABIR program consists of seven interrelated program elements:
A schematic diagram illustrating the analysis and synthesis leading to selection of
the scientific program elements for NABIR is provided in Fig. 4, and detailed
supporting information derived from recent R&D needs assessments is provided in
Table 2.
The rationale for selecting these seven interrelated program elements is provided
below:
Biotransformation and Biodegradation. More knowledge is needed
about mechanisms and pathways for biotransformation and biodegradation,
especially for metals, radionuclides, and mixtures of contaminants. Moreover, the
role of microbial consortia and how organisms work together to degrade or
transform contaminants must be understood better.
Figure 3. A schematic diagram showing the seven program elements of the
NABIR Program, the integrating role of the field research centers, and the
partnerships to enable implementation of new bioremediation technologies.
Figure 4. Analysis and synthesis of NABIR Program needs.
Table 2. Bioremediation research and development needs as identified in recent
reviews and addressed by NABIR Program Plan.
Table 2 (cont.). Bioremediation research and development needs as identified in recent
reviews and addressed by NABIR Program Plan (continued).
Community Dynamics and Ecology. More knowledge is needed to
understand the composition, structure, and function of the large number of
organisms present in natural systems. Advanced molecular and biochemical
methods should be applied to identify populations, evaluate evolution in response
to exposure to contaminants, and understand the influence of a variety of
environmental factors on biodegradation and biotransformation rates and processes.
In addition, better understanding of the factors influencing the survival and
effectiveness of introduced organisms needs to be developed.
Biomolecular Science and Engineering. The potential of molecular
manipulation to enhance bioremediation remains untapped. To realize this potential,
more information is needed to analyze genes, proteins, and regulatory elements of
critical molecules for bioremediation. Knowledge of structure and function
relationships is also needed to understand the enzymatic mechanisms for
detoxification. Building on this foundation, organisms could be engineered with
superior degradative capabilities. However, ethical, legal, and social issues
associated with the development and utilization of engineered biodegradative
organisms must be addressed to the satisfaction of the public and regulatory
agencies before they can be used.
Biogeochemical Dynamics. Better methods are needed for measuring the
in situ distribution of organisms with potential for biodegradation, and for
understanding the environmental factors that control these distributions. In addition,
the important role of interfaces as it affects the nature and rate of biogeochemical
processes needs to be understood better, especially the role of solid-liquid interfaces,
liquid-gas interfaces, and the interface between two immiscible liquids.
Bioavailability of contaminants and nutrients is another key issue that must be better
understood.
Assessment. Advanced and real-time measurement tools are required to
understand and monitor the processes responsible for bioremediation and assessing
how effective they are. Key needs include developing new methods for assessing
biodegradation rates and activities, developing noninvasive or minimally invasive
techniques for characterizing a site and monitoring loss of contaminants from the
site, developing diagnostic techniques for interpreting measurements, and
determining a scientifically defensible strategy for identifying bioremediation end
points.
Acceleration. Better understanding of the factors that limit the rate of
in situ bioremediation is needed so that effective methods for accelerating
biogeochemical processes can be developed. Better methods should be developed
for supplying nutrients and microorganisms for in situ bioremediation, and
for increasing the bioavailability of contaminants. To achieve this, the underlying
transport processes need to be better understood, innovative biostimulation and
bioaugmentation methods as well as better methods for delivering acceleration
agents to the subsurface should be developed.
System Integration, Prediction, and Optimization. More knowledge
is required to predict and optimize the effectiveness of bioremediation. Mechanistic
models that quantitatively describe biotransformation and biodegradation processes,
community dynamics, and biogeochemical dynamics must be improved and then
linked together to develop engineering models for field-scale design, optimization,
and assessment of bioremediation. Systems to integrate and disseminate new
information are also needed.
Close coordination and interaction among researchers investigating topics in these
program elements will be required to overcome the traditional barriers to cross-fertilization and integration of knowledge and ideas. The field research centers
described below, as well as information systems, shared models, and R&D shared
infrastructure will be the major vehicles for achieving this interaction.
FIELD RESEARCH CENTERS
There is broad agreement among the R&D community about the need for dedicated
research sites where the biogeochemical processes that contribute to bioremediation
can be investigated. Field research centers will also be the vehicles for identifying
applied research needs. NABIR will establish three field research centers where such
site-based investigations can be carried out. The field research centers will be
selected to address a range of hydrogeologic environments and contaminant mixtures
that are important to DOE. The concept for operating these field research centers
is illustrated in Fig. 5. The centers will support four types of activities:
