Progress 02/01/02 to 09/30/05
Outputs
This project, which began in February 2002, has addressed site to site variability in bioremediation. We have developed lab scale biotreatability testing protocols that assist in designing successful bioremediation treatments for each site. Experiments performed throughout this project have demonstrated that respirometry can be useful in assessing microbial activity in relation to biodegradation at both the bench-scale and pilot scale, and for assessing toxicity effects on microorganisms and their activity. The results of these experiments have been presented and published in various venues. In addition, we have partnered with an environmental consulting company who is actively marketing the use of treatability testing for the application of bioremediation to contaminated soils, water or air streams. More recently, we have observed that the biofilms, which are formed by the microorganisms as they attach to a solid substrate such as soil or the biofilter substrate, will
vary in composition and structure in response to variables such as the type of substrate (e.g. soil versus polymeric plastic) and the chemical environment in which the microorganisms grow (e.g. carbon source and amount of nutrients). In turn, this variance in biofilm composition and structure will affect the uptake and ultimately the biodegradation of organic contaminants. Our current research has focused on the characterization of the physical and chemical nature of the biofilms as a function of these variables. We have isolated a PAH degrader and we are currently assessing the optimal conditions for biofilm formation by this degrader.
Impacts
The time frame and cost of doing biotreatability testing for each bioremediation site could prohibit its use in determining the best treatment train. The use of respirometry in lab scale biotreatability testing is less labor intensive than plate counting, and thus would allow faster and more cost effective biotreatability testing for each project site. Our results indicate that respirometry is as effective or even more effective than plate counts in assessing microbial activity as it relates to biodegradation of the contaminant. Based on this information, we have developed a biotreatability protocol that is less costly and would allow environmental services companies to design a bioremediation treatment train for contaminated sites. We are continuing to update this protocol to include other variables such as biofilm formation.
Publications
- No publications reported this period
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Progress 10/01/03 to 09/30/04
Outputs
This project, which began in February 2002, addresses site to site variability in bioremediation and had proposed to develop lab scale biotreatability testing protocols that assist in designing successful bioremediation treatments. Experiments (in connection with other projects) were performed to demonstrate the use of respirometry monitoring to assess microbial activity as it relates to bioremediation. Treatability tests were performed on 1) petroleum contaminated soils, 2) sediments obtained from the Ala Wai canal, containing heavy metals and chlorinated organic compounds and 3) compost/perlite mixture (for use in a biofilter) contaminated with odorous amine compounds. The concentrations of amendments, such as fertilizers and additional carbon substrates, as well as moisture and oxygen content were varied. Good correlation between CO2 production, O2 consumption and plate count analyses was observed for many of the biotreatability experiments performed. A more
complex media, such as a non-sterilized soil with petroleum contaminants containing communities of microorganisms was studied; the correlation between respirometry and contaminant degradation was better than the correlation between plate counts and contaminant degradation. This indicates that, in addition to being less labor-intensive, respirometry is a better indicator (than plate counts) of microbial activity related to biodegradation. Substrate-induced respirometry is used to estimate total biomass carbon, and to determine the magnitude of contaminant toxicity on microbial activity. The microbial respiratory response initially decreased due to contaminant toxicity, but showed that the microbes were able to acclimate and metabolize the contaminant. Respirometry was used in the scale up of a biofilter for treatment of an odorous waste air stream. Bench-scale batch treatability experiments were performed to determine the optimal nutrient and contaminant concentrations for
biodegradation of a long-chain amine compound, which is odorous, and expected to be present in the waste air stream of paint booths. Based on respirometry and gas chromatography results, it was determined that this contaminant was biodegraded by the microbial communities present in the compost/perlite mixture. A pilot scale biofilter was designed and constructed, and respirometry was used to monitor microbial activity. Difficulties in introducing the contaminant to this pilot scale biofilter did not allow for additional experiments to be completed, but initial results indicated that respirometry could be used at the pilot scale for monitoring microbial activity. In summary, our experiments have demonstrated that respirometry can be useful in assessing microbial activity in relation to biodegradation at both the bench-scale and pilot scale, and for assessing toxicity effects on microorganisms and their activity. The results of these experiments have been presented and published in
various venues. In addition, we have partnered with an environmental consulting company who is actively marketing the use of treatability testing for the application of bioremediation to contaminated soils, water or air streams.
Impacts
The time frame and cost of doing biotreatability testing for each bioremediation site could prohibit its use in determining the best treatment train. The use of respirometry in lab scale biotreatability testing is less labor intensive than plate counting, and thus would allow faster and more cost effective biotreatability testing for each project site. Our results indicate that respirometry is as effective or even more effective than plate counts in assessing microbial activity as it relates to biodegradation of the contaminant. Based on this information, we have developed a biotreatability protocol that is less costly and would allow environmental services companies to design a bioremediation treatment train for contaminated sites.
Publications
- Romano, R.T. 2004. Bioremediation of Long-Chained Aliphatic Amines. MS Thesis. Univ. Hawaii, Manoa. 81p.
- Sylva, T., Kinoshita, C., Romano, R., Toma, M., Tsang, S. and Chang, K. 2003. Bioremediation of Petroleum Impacted Soils from Investigation-derived Wastes. Remediation Journal. 14(4):79-90.
- Tsang, S.K., Romano, R., Chang, K., Sylva, T. and Kinoshita, C.M. 2002. Bioremediation of Petroleum Impacted Soils. Proceedings of the Institute of Biological Engineering. Vol. 3, 11-17.
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Progress 10/01/02 to 09/30/03
Outputs
In year two of this project, a pilot scale study was initiated in order to determine if respirometry data and bacterial counts obtained from laboratory-scale experiments could be used to predict similar conditions at the pilot scale. The compost/perlite laboratory scale experiment was scaled up for biotreatability testing of a compost biofilter for odorous compounds. The only difference between the pilot scale system and the laboratory scale system was that the contaminant in the pilot scale experiment, would be introduced by a saturated air stream rather than mixed into the media. Respirometry, plate count and contaminant degradation data was obtained in laboratory scale bioreactors and indicated efficient biodegradation of an odorous compound, octadecyldimethylamine (ODA), that is found in paint booth emissions. The pilot scale biofilter was constructed, and fitted with ports for respirometry monitoring, sampling for microbial counts and contaminant concentration
monitoring. As expected, the respirometry and bacterial count data corresponded well with one another and indicated an increase in microbial activity in the non-sterile biofilter after introduction of the contaminant, with no corresponding increase in the sterile biofilter. Low concentrations of the contaminant could be delivered to the biofilter media because of the contaminant's low volatility. Monitoring its concentration in the gas phase was difficult due to the detection limit of the gas chromatographic method being used for monitoring the concentration. Therefore, it was not possible to determine if efficient contaminant biodegradation was achieved in the biofilter system. Additional optimization of the contaminant delivery system and/or the GC method is needed. Although contaminant biodegradation was not confirmed in this experiment, it is clear that the respirometry and plate count data correspond with each other at the pilot scale. And a similar increase in respirometry and
plate counts was observed in the laboratory scale bioreactor experiment, indicating that the respirometry data can be useful and carries over between the laboratory and pilot scales.
Impacts
The similarity between the respirometry results at the laboratory and pilot scales provides evidence that laboratory scale treatability tests which are much simpler and less expensive can provide useful information for scale up. The results of the treatability tests are necessary for the environmental engineer that is designing a bioremediation plan for a specific site to determine optimum conditions, such as moisture content, and time needed for biodegradation. In addition, since plate counts and respirometry correspond well with one another, the use of the less labor intensive respirometry method when monitoring either laboratory or pilot scale experiments is proving to be feasible. Overall, this study may result in more useful data being generated at lower cost to the consulting engineer, who can use this data to develop a more efficient bioremediation plan.
Publications
- No publications reported this period
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Progress 10/01/01 to 09/30/02
Outputs
This project, which began in February, 2002, addresses the issue of site to site variability in bioremediation and proposes to develop lab scale biotreatability testing protocols that will assist in designing a successful bioremediation treatment for each site. Experiments (some in connection with other projects) have been performed to demonstrate the use of respirometry monitoring to assess microbial activity as it relates to bioremediation. Treatability testing was performed on 1) soils to which petroleum contaminants were added, 2) contaminated sediments obtained from the Ala Wai canal, which contained heavy metal and chlorinated organic compounds and 3) compost/perlite mixture (for use in biofilter) contaminated with odorous compounds. The amendments include fertilizers and additional carbon substrates. Good correlation between CO2 production, O2 consumption and plate count analyses was observed for many of the experiments performed within the biotreatability
system. Substrate-induced respirometry is used to estimate total biomass carbon. The "maximum initial respiratory response" (% CO2 before the exponential growth phase) is measured following the addition of an easily metabolized carbon substrate, such as glucose, and can be related to the amount of microbial biomass carbon present in the soil sample. This technique has proven to be quite useful in the treatability tests. Within a carefully controlled experiment, where known numbers of microorganisms were inoculated into sterile soils, the substrate-induced production of CO2 (%) and the calculated biomass carbon correlated well with plate counts. When a more complex media, such as a non-sterilized soil with petroleum contaminants containing communities of microorganisms, was used, there was only a small correlation between plate counts and respirometry, although the correlation between respirometry and contaminant degradation was better when compared to the correlation between plate
counts and contaminant degradation. This indicates that, in addition to being less labor-intensive, respirometry is a better indicator (when compared to plate counts) of microbial activity related to biodegradation. Substrate-induced respirometry was also used to determine toxicity effects of the contaminant on microbial populations. The data confirms what was expected, that the microbial populations within this soil are initially affected by the contaminant (smaller respirometry response), but after about two weeks, they are able to acclimate to the contaminant and metabolize this new carbon substrate. Once they have acclimated to the new carbon substrate, if a different carbon substrate is added, the microbes need to again acclimate to that substrate, and another lag phase is observed. This experiment demonstrates how respirometry is useful in studying related processes that could affect the desired biodegradation process. In summary, our experiments have demonstrated that
respirometry can be useful in assessing microbial activity in relation to biodegrading activity, and for assessing toxicity effects on microorganisms and their activity.
Impacts
The time frame and cost of doing biotreatability testing for each bioremediation site could prohibit its use in determining the best treatment train. The use of respirometry in lab scale biotreatability testing is less labor intensive than plate counting, and thus would allow more efficient, cost effective biotreatability testing for each project site. Our results indicate that respirometry is as effective or even more effective than plate counts in assessing microbial activity as it relates to biodegradation of the contaminant. Based on this information, the expectation is that we will be able to develop a relatively simple biotreatability protocol that is less costly and would allow environmental companies to better design a bioremediation treatment train for contaminated sites.
Publications
- No publications reported this period
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