PHase III, Inc. Biotreatability Analysis
A Phased Analytical Approach to Successful Bioremediation Projects

The parameters 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.

Microbial 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.

However, 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 depletion.

Biotreatability 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 conditions.

Biotreatability 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.

It 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.

The 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.

Identification and Isolation of Indigenous Microbes

An 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.

PHase 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 microbes.