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BRT owns and operates full-scale microbiological laboratories with analytical capabilities to evaluate biological processes occurring at a given site. Laboratories are staffed with Ph.D. environmental microbiologists, laboratory technicians and environmental scientists. Studies and analysis’ can be designed to meet the specific needs/questions of a given site. These serve as a litmus test to determine if bioremediation is a viable option and give valuable information even if bioremediation is not the end goal.

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Bacteria are enumerated for a variety of purposes that include monitoring of overall or specific bacterial populations, detection of specific phenotypic groups, or ensuring compliance with water quality regulations.   The bacterial population from a field site can be evaluated via two culture-based techniques:  plate counts and Most Probable Number (or MPN).

Plate Counts – Plate counts are typically used to enumerate the heterotrophic bacterial population as well as populations capable of utilizing common environmental contaminants like petroleum hydrocarbons and aromatics under aerobic conditions.  Aliquots of groundwater (or soil samples) are serially diluted and spread on appropriate agar plates.  Heterotrophic plates contain rich carbon and nutrient sources that support the growth of a wide variety of bacteria. Heterotrophic plate counts represent the total culturable microbial population in the site matrix material.  The contaminant-degrader plates contain nutrients with the contaminant of concern provided as the sole carbon source.  Contaminant-specific plate counts represent the number of bacteria able to utilize the contaminant of concern as a carbon source.  Bacterial colonies that grow on these plates are counted and reported as colony forming units per milliliter (CFU/ml).  Plate counts are generally used for enumeration of bacteria using aerobic biodegradation processes.  The plate count method may be modified for use in monitoring anaerobic bacterial populations, depending on the contaminant of concern, as well as the alternate electron acceptor in question.  Anaerobic heterotrophic populations and selenate-reducing populations serve as examples of populations where plate counts may be used for enumeration in an anaerobic setting.

MPN Analysis-The MPN technique provides a statistical estimate of culturable units and assumes such units are randomly distributed within a sample.   The method consists of taking samples of site matrix material, diluting, incubating the sample in a suitable culture medium, and observing whether any growth of the organism has taken place.  Functionally, the MPN test is based on dilution of a target microorganism to extinction.  Although the MPN technique may be used for aerobic processes, it is more typically employed for analysis of biodegradation of contaminants of concern under anaerobic conditions such as sulfate-reducing.

BRT has implemented a streamlined approach for the evaluation of bioremediation potential for any particular  site.  With the uncertainties of bioremediation and the in situ environment at a given site, it is imperative to understand the site characteristics prior to attempting to stimulate the native biota. BRT can determine upfront if a site is a biological candidate. As a whole, three things are needed for the bioremediation process to occur, oxygen, nutrients and bacteria. If all three are not present, biological activity will not occur. Through laboratory testing, BRT examines the missing factors and stimulates the sites native bacteria to spur biodegradation. Once the study is complete, a cost to closure can be determined. Any guess work is taken out of the equation and a more detailed and accurate scope of work can be defined all while being more cost effective.

The Treatability Study consists of a laboratory kinetics study in combination with an evaluation of field parameters, groundwater quality data and site information (Subsurface Delineation and/or Characterization Report).  The Treatability Study is implemented to determine if bioremediation is a viable option at the site.

The collection and evaluation of groundwater field parameters are an integral part of the Treatability Study.  As oxygen is commonly one of the main limiting factors in aerobic hydrocarbon biodegradation, dissolved oxygen and oxidation/reduction potential are two of the field parameters evaluated to determine baseline oxygen content and the likely bioavailability of supplemental oxygen, respectively.

As specifically related to bacterial viability, pH and temperature are important because extreme values in either of these parameters is detrimental to bacterial activity.  Extreme pH values (i.e., less than 5 or greater than 10) are typically unfavorable for microbial activity. Optimal microbial activity tends to occur under neutral pH conditions (i.e., in the range of 6–8).

The kinetics portion of the Treatability Study evaluates the degradation rate of the contaminants using an indigenous bacterial culture developed with the contaminant(s) of concern as the primary carbon source.  Data generated from the kinetics investigation provide evidence as to whether the native bacteria may be nutrient limited, oxygen-limited, and/or whether the site may benefit from addition of a site-specific bacterial culture.  Treatments are prepared with site matrix material.  Contaminant removal over time is evaluated in a minimum of 4 treatment groups.

All biological systems require a balanced blend of macro- and micro-nutrients as metabolic stimulants and growth enhancers, and can fail if this nutritional ratio is improperly balanced. Thus, nutrient concentrations are a growth limiting factor. It is important to note that not all bacteria require the same nutrients nor can any one utilize all kinds. BRT’s in house analysis can determine exactly what nutrients are lacking and determine what is needed for efficient bioremediation.[/prk_ac_single]

As part of the initial plating evaluation, BRT also screens samples for the presence of common environmental pathogens. BRT must rule out the presence of pathogens before culturing from a site in order to prevent further growth of potentially harmful bacteria.

As part of the initial plating evaluation, BRT also screens samples for the presence of common environmental pathogens. BRT must rule out the presence of pathogens before culturing from a site in order to prevent further growth of potentially harmful bacteria.

DNA isolation and analytical techniques are used to determine bacterial community structure in situ. DNA is directly extracted from environmental samples, purified, and amplified via PCR technology.  Bacterial community DNA is subsequently analyzed.  Using a combination of molecular tools and sequence analysis, the phylogenies of the bacterial community structure can be elucidated, allowing for the development of more efficient growth conditions and nutrient supplementation as well as the demonstration of the shift in community structure between contaminated and pristine sites.