We provide information on biological treatments whether used alone or in the combination with chemical and physical treatments. As an example we cite the following as a guide in bioremediation treatments---processes which use component microorganisms and the enzymes they produce to transform or degrade contaminants found in groundwater, surface water, soil, sediment, and sludges. Biological treatment processes include bioreactors, biofilters, ponds and lagoons, land treatment, composting, and subsurface aerobic/anaerobic treatment.
1. We recommend the establishment of a baseline species diversity analysis before commencing any significant activity. This would consist of adequate sampling of the materials to be treated taking into consideration any heterogeneity of the parent material present or environmental parameter differences (moisture or aeration differences, etc.). Such an analysis requires 4 ounce samples taken for Total Aerobic Heterotrophic plate counts from which a determination as to the number of predominating distinct colony types can be made. The strains of the predominate colony types are then analyzed by gas-chromatography fatty-acid methyl ester (GC-FAME) analysis and BiologTM for identification. It has been our experience that this generally entails identification of between three and eight bacterial types.
2. If indigenous organisms are to be used, point 1 is repeated one day after any parameter change, i.e., fertilization for stimulations of bacterial population growth. This is also true following the inoculation of the site with introduced bacteria. With introduced bacteria, we recommend through examination of the inoculum mix prior to the introduction. This may entail isolation of strains of a mix and their identification by gas chromatography coupled with characterization by 95-phenotypic tests of their carbon source utilization patterns. With this information and the familiarity with these strains gained in this process, it oft times enables later monitoring of the strains to consist of recognizing shifts in the ratio of introduced strains with changes in the hydrocarbon profiles.
3. Monitoring should generally be done on a frequent schedule initially (dependent upon the nature of the project) repeating the activity described in step 1. Typically with thorough characterization and familiarization of predominant strains at the site over the first interim of monitoring, one is in a position to assess the effectiveness of various environmental parameter changes and their effect on the rate of bioremediation.
4. Strain characterization may include use of the site's materials in laboratory degradation studies which provide not only information as to which strains degrade the material but also the rate differences between strains be they introduced or indigenous. Using a 96-well plate format we often look at the isolated strains' abilities to breakdown benzene, toulene and the material of interest (i.e., gasoline, diesel, oil, trichloroethylen, etc.). We can screen either for various substrate utilization patterns or screen a larger number of strains against fewer compounds. Such kinetic plate assays run continuously for typically 18 to 24 hours and provide a great deal of information. We recommend this assay to those involved in the research arena or sophisticated clients who can make use of the generated data or are our clients on a consultant basis where we can further the client's knowledge.
5. We consult on these types of projects and use our video-image analysis capabilities in documenting the work at the site and changes which may be apparent in the physical nature of the site or in specimen we work with in the laboratory. We look forward to making a proposal to you for our consulting services and working to solve you or your client's remediation problem.