2005 Progress Report: Development and Evaluation of Field Sensors for Monitoring Anaerobic Dehalogenation after Bioaugmentation for In Situ Treatment of PCE and TCEEPA Grant Number: R828772C011
Subproject: this is subproject number 011 , established and managed by the Center Director under grant R828772
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: HSRC (2001) - Western Region Hazardous Substance Research Center for Developing In-Situ Processes for VOC Remediation in Groundwater and Soils
Center Director: Semprini, Lewis
Title: Development and Evaluation of Field Sensors for Monitoring Anaerobic Dehalogenation after Bioaugmentation for In Situ Treatment of PCE and TCE
Investigators: Ingle, James D.
Institution: Oregon State University
EPA Project Officer: Lasat, Mitch
Project Period: September 1, 2001 through August 31, 2006
Project Period Covered by this Report: September 1, 2004 through August 31, 2005
RFA: Hazardous Substance Research Centers - HSRC (2001) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management
The purpose of this study is to develop, refine, and use sensors and field instruments, based on redox indicators and other reagents as on-site, on-line, or in-situ monitoring tools for assessing and optimizing redox and related conditions for treatment of PCE and TCE with dehalogenating cultures. These sensors and field instruments will be calibrated for evaluating redox conditions and the effectiveness of dechlorination in collaborative situations involving a bioaugmentation approach in packed sediment columns.
Better field and portable monitoring techniques for redox status and related conditions for bioremediation are needed for: (1) the evaluation of laboratory samples, models such as columns and PAMs, and subsurface conditions at a site; (2) continued assessment of the progress of remediation; and (3) examination of the effects of bioaugmentation in field and laboratory experiments. We have demonstrated that redox sensors based on redox indicators exhibit promise for monitoring environmental redox levels. Research is needed to: (1) identify and compare the response of these indicators during bioaugmentation; (2) improve the monitoring devices and methodology (flow cells, fiber optic probes, sampling) for practical use; (3) demonstrate that these devices and methodology can be employed for on-line or in-situ monitoring of the status of anaerobic dehalogenating cultures in laboratory systems; and (4) develop new sensing species, methods, instrumental components and sensor designs for on-line monitoring of the status of dechlorinating systems in columns and PAMs packed with soil, microcosm bottles, and sub-surface systems in the field.
Redox indicators immobilized on transparent films have been shown to be able to differentiate between different microbial redox levels and to predict whether conditions are appropriate for reductive dechlorination to occur. These redox indicators, which are incorporated into specially constructed flow sensors and fiber optic probes, will be deployed in collaborative experiments for calibration and demonstration of their applicability. These experiments will involve continuous monitoring of the redox conditions of cultures inside columns and PAMs packed with soil and enriched with halorespiratory cultures as a tool for spatial monitoring of dechlorination, and to improve conditions necessary for effective dechlorination of PCE and TCE. The design and characteristics of the redox sensor monitoring systems will be improved for low oxygen permeation and portability for easy operation in the lab and field. In addition, we seek to investigate alternative sampling/reagent/detection systems, quantitative measurement of concentrations of reductants, and fiber optic sensors. Other probe species such as quinones may provide unique information about dechlorinating activity.
We have improved portable, flow-based monitoring systems based on immobilized redox indicators and used them to successfully examine redox conditions in microcosm and bottles containing a dechlorinating culture (Evanite culture). We developed a new method to determine the “reductive capacity” (RC) or “effective concentrations of reductants” in aqueous anaerobic samples taken from microcosm bottles and aquifer columns. A small volume of deaerated redox indicator solution in a septum-sealed spectrometer cuvette is mixed and reacted with an aqueous sample obtained with a gas-tight syringe from a packed column or microcosm bottle. Reductants in the sample reduce the indicator if the formal potential of the reductant couple is equal or below that of the indicator. From the decrease in absorbance of the indicator, the “reductive capacity” can be calculated, which is typically 200 to 600 μM for active microcosms and 50 to 300 μM in bioaugmented packed columns under active reductive dehalogenation. This technique has been successful at identifying significant changes in the redox conditions in columns and microcosms (e.g., a 50% drop in RC when the column is disturbed). We anticipate the eventual automation of this measurement to allow for continuous monitoring.
We have employed a fiber optic probe with immobilized redox indicator film at its tip to monitor redox status. The probe is used is conjunction with a light source and CCD spectrometer to monitor the absorbance of the indicator. This probe can be easily positioned in soil columns and provides for true in-situ monitoring. Redox indicators placed on the fiber optic probe respond comparably to those installed in flow cells and connected by flow loops and allow for true in-situ monitoring.
To evaluate sensors and probes, we have constructed a PVC-based column with suitable ¼-28 ports for installation of redox flow monitoring setups and ½-20 ports to install the fiber optic probe. The column was packed with sediment from the Hanford Department of Energy (DOE) site and inoculated with the Evanite culture. As observed during previous microcosm experiments with the Evanite culture, the indicator cresyl violet is about one-half or fully reduced at all ports indicating suitable conditions for dehalogenation. Also, we have successfully used the redox flow sensor and the fiber optic probe for monitoring conditions and columns in labs in environmental engineering.
We have begun to probe the applications of other redox indicators, particularly quinones, and vitamin B12 to the array of indicators available to study environmental redox processes. Quinones are of particular interest as they participate in numerous cellular reactions and appear to influence “reductive capacity” measurements.
Also, we have evaluated long-path flow cells and automated syringes for improved on-line measurements of redox-active species (e.g., S(-II), Fe(+II)) and for push-pull sensing methods. We have begun research on construction of a lab-on-a-chip device that can be employed for on-site or in-situ measurements of environmentally relevant redox species.
Current Students on Project
Peter Ruiz-Haas is the primary Ph.D. graduate student on the project.
Defne Cakin is a Ph.D. graduate student and is working on developing new monitoring techniques for the project, with a particular emphasis on low level detection of reductants and oxidants with specially developed long-path cells.
Corey Koch is a Ph.D. graduate student and is working on automation and development of microfluidic devices and procedures for field and in-situ determination of environmental information.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
|Other subproject views:||All 7 publications||1 publications in selected types||All 1 journal articles|
|Other center views:||All 158 publications||63 publications in selected types||All 60 journal articles|
||Jones BD, Ingle Jr JD. Evaluation of redox indicators for determining sulfate-reducing and dechlorinating conditions. Water Research 2005;39(18):4343-4354.||
Supplemental Keywords:RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Waste, TREATMENT/CONTROL, Remediation, Environmental Chemistry, Treatment Technologies, Environmental Microbiology, Hazardous Waste, Bioremediation, Ecological Risk Assessment, Hazardous, Environmental Engineering, plant-based remediation, degradation, contaminated sediments, microbial degradation, biodegradation, contaminated soil, contaminants in soil, phytoremediation, plant-microbe system, bacterial degradation, groundwater
Progress and Final Reports:Original Abstract
Main Center Abstract and Reports:R828772 HSRC (2001) - Western Region Hazardous Substance Research Center for Developing In-Situ Processes for VOC Remediation in Groundwater and Soils
Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R828772C001 Developing and Optimizing Biotransformation Kinetics for the Bio- remediation of Trichloroethylene at NAPL Source Zone Concentrations
R828772C002 Strategies for Cost-Effective In-situ Mixing of Contaminants and Additives in Bioremediation
R828772C003 Aerobic Cometabolism of Chlorinated Aliphatic Hydrocarbon Compounds with Butane-Grown Microorganisms
R828772C004 Chemical, Physical, and Biological Processes at the Surface of Palladium Catalysts Under Groundwater Treatment Conditions
R828772C005 Effects of Sorbent Microporosity on Multicomponent Fate and Transport in Contaminated Groundwater Aquifers
R828772C006 Development of the Push-Pull Test to Monitor Bioaugmentation with Dehalogenating Cultures
R828772C007 Development and Evaluation of Field Sensors for Monitoring Bioaugmentation with Anaerobic Dehalogenating Cultures for In-Situ Treatment of TCE
R828772C008 Training and Technology Transfer
R828772C009 Technical Outreach Services for Communities (TOSC) and Technical Assistance to Brownfields Communities (TAB) Programs
R828772C010 Aerobic Cometabolism of Chlorinated Ethenes by Microorganisms that Grow on Organic Acids and Alcohols
R828772C011 Development and Evaluation of Field Sensors for Monitoring Anaerobic Dehalogenation after Bioaugmentation for In Situ Treatment of PCE and TCE
R828772C012 Continuous-Flow Column Studies of Reductive Dehalogenation with Two Different Enriched Cultures: Kinetics, Inhibition, and Monitoring of Microbial Activity
R828772C013 Novel Methods for Laboratory Measurement of Transverse Dispersion in Porous Media
R828772C014 The Role of Micropore Structure in Contaminant Sorption and Desorption