III, Inc. Biotreatability Analysis
A Phased Analytical Approach to Successful
generally measured in a biotreatability study include microbial
enumeration's and measurement of microbial activities. Typically,
total viable plate counts of heterotrophic and petrophillic
microorganisms are performed over time and allows an indirect
measure of the success of the bioremediation treatment regime.
More importantly though, enumeration's of the microorganisms
biodegrading the contaminant and utilizing it as a carbon
and energy source are performed. Increases in the microbial
population overtime indicates favorable environmental conditions
have been created for the microbial population. This also
indicates that the bioremediation treatment has successfully
enhanced the activities of the requisite microorganism.
activities are monitored by measuring rates of microbial respiration.
This is performed by measuring the rate of oxygen consumption
or carbon dioxide production. An increase in microbial respiration
in experimental treatments relative to untreated controls
indicate the bioremediation strategy successfully enhanced
the biological activity.
the most direct evidence of bioremediation efficacy is the
monitoring of contaminant removal and biodegradation rates.
Appropriate controls are used in the biotreatability studies
to quantitatively assess the biodegradation of the contaminant.
Heat or chemically sterilized controls are used to determine
any physical or chemical fate removal mechanisms of the contaminant(s).
Untreated controls are used to quantitatively evaluate the
effect of the treatment strategies, including oxygen addition,
nutrient addition, and bioaugmentation on the biodegradation
rates. A mass balance calculation of contaminant is performed
which provides a quantitative assessment of the biological,
physical and chemical processes responsible for the contaminants
studies can evaluate the fate of a contaminant under aerobic
or anaerobic conditions. Interestingly, some environmental
contaminants are more susceptible to mineralization under
sequential anaerobic-conditions. Biotreatability studies can
be designed to evaluate a contaminant rate under these conditions
and provide cost effective ways to induce the selective environmental
studies typically entail sampling at several different times
during the study to track the performance of the simulated
systems and to predict the formulation of undesirable intermediate
degradation products. In fact, the analytical component of
these studies can be the most significant feature and can
represent the highest percentage of cost as well.
is important to understand that not all bioremediation projects
have biotreatability studies conducted as part of their scope
of work. In many cases, physical limitation associated with
a project can far outweigh some of the scientific issues,
so that field pilot demonstrations become more practical or
necessary. Biotreatability studies are conducted when there
are specific issues related to the scientific aspects of a
project that warrant quantification. These studies can span
1 to 6 months time depending upon the factors being evaluated
and the particular contaminants of interest.
information resulting from a biotreatability study are organized
in a clear, readable format with recommendations for treatment
strategies. The untreated control, not receiving any treatment,
demonstrates significantly reduced rates of biodegradation.
Similarly, an increase in the microbial population is observed
over time due to the same treatment strategy, while the untreated
control shows very little increase. Treatment recommendation
will also be included in the biotreatability report. Nutrient
formulations will be calculated according to information gathered
from the laboratory studies and the known theoretical stoichiometry
of the specific microbial process. Required rates of air flow
for in-situ bioventing or aeration of groundwater will be
determined and recommendations provided. Rates of peroxide
addition to achieve a target dissolved oxygen concentration
will also be included in the biotreatability report as well
as recommendations regarding bioaugmentation and application
rates of microbial innoculants. However PHase III, Inc. consultation
does not stop after the report. Consultation and engineering
design regarding bioremediation is available after the initial
laboratory study and can be made on a continuous basis during
the remediation project.
and Isolation of Indigenous Microbes
important component of the biotreatability study is the characterization
gathered, including isolation and identification of specific
microbial strains, can add greatly to the understanding of
the microbial process that are occurring or that can be stimulated
to occur at the site. This will facilitate the development
of optimal system designs and treatment techniques.
III, Inc. has pioneered a technique of first isolating indigenous
microbes that demonstrate a high propensity to biodegrade
the in-situ target contaminates, then secondly culturing them
in high concentrations in the laboratory for later reinoculation
at the site. This can be done as part of the biotreatability
study and can suggest a possible strategy of bioaugmentation
for the site. If the indigenous strains are indeed viable,
quite often, biodegradation rates can be increased 3 - 10
times using the technique of applying enhanced indigenous
strains from the site in combination with selected specific
strains from PHase III, Inc. library of laboratory cultured