4.2 Performance Criteria
Table 3. Expected performance and performance confirmation methods.
Expected
Performance Confirmation
Performance
Actual (post demo)
Performance Metric
Method
Criteria
(pre demo)
Primary Criteria (performance objectives) (Qualitative)
Ease of use
Minimal operator
Experience from other
training required
demonstration operations.
Stand establishment in plots.
Primary Criteria (performance objectives) (Quantitative)
Measurable
Statistical analyses of
Statistical analyses of
Use of factorial analysis and
treatment benefit
concentration data or
concentration data or
biomarker-GDD normalized data
degradation rates
degradation rates
to show statistical significance
for plant treatments for specific
petroleum fractions
Measurable
Statistical analyses of
Statistical analyses of
Statistical analyses of microbial
treatment benefit
microbial data
microbial data
data showing fertilizer effect on
manifested in
bacteria and plant effect on fungi
microbial changes
4.3 Data Assessment
Performance data are provided and discussed in section 4.1. Significant plant benefits for
depleting petroleum fractions were observed. These data show that rhizosphere enhancement
provides a benefit relative to fertilizer alone or controls. Minimal personnel training is needed to
implement this technology. Heath and safety requirements can be met with minimal input
because seeding and fertilizing are relatively safe operations. Operation of rhizosphere-enhanced
remediation systems was designed to be self-sustaining after seeds are established. Limitations
are that this is not a fast treatment technology, and monitoring requires knowledge of the
processes involved.
4.4 Technology Comparison
See section 4.2. for a description of performance criteria for rhizosphere-enhanced remediation.
A summary of remediation techniques highlighting their main features is provided below. The
approaches are described in approximate order from simplest to the most aggressive; the simpler
approaches cost less, but generally require more time for treatment (Figure 7). The more
aggressive approaches, such as bioventing, bioreactors, and those that require soil excavation and
infrastructure are generally not practical for remote locations.
4.4.1 Natural Bioremediation
Passive or intrinsic bioremediation is the "natural" bioremediation of a contaminated site by
indigenous microorganisms. Many contaminants are degraded by indigenous microorganisms,
although the rate of degradation is often too slow for practical benefit. A challenge with passive
bioremediation is that it is difficult to monitor, and therefore difficult to predict migration and
decay. In general, one or several factors are sub optimal for biodegradation to occur. Most of the
following techniques have been developed to reduce the limitations.
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