Grantee Research Project Results
1998 Progress Report: Role of Microbial Metabolism and Cometabolism in Treating Mixtures of Biodegradable and Nonbiodegradable Chemicals in Granular Activated Carbon Columns
EPA Grant Number: R826170Title: Role of Microbial Metabolism and Cometabolism in Treating Mixtures of Biodegradable and Nonbiodegradable Chemicals in Granular Activated Carbon Columns
Investigators: Speitel, Gerald E.
Institution: The University of Texas at Austin
EPA Project Officer: Aja, Hayley
Project Period: December 1, 1997 through November 30, 2000
Project Period Covered by this Report: December 1, 1997 through November 30, 1998
Project Amount: $304,688
RFA: Exploratory Research - Environmental Engineering (1997) RFA Text | Recipients Lists
Research Category: Safer Chemicals , Land and Waste Management
Objective:
Granular activated carbon (GAC) is widely used to treat water contaminated with synthetic organic chemicals (SOCs). Practically no information is available on combining adsorption and biodegradation to treat mixtures of biodegradable and nonbiodegradable SOCs, a very common problem. Biodegradation can increase the GAC service life and improve process performance relative to adsorption alone. This research seeks to: (1) develop a better understanding of the effect of biodegradation on the service life of GAC columns, (2) identify conditions where metabolism of SOCs is advantageous, and (3) identify conditions where cometabolism of SOCs is advantageous.Progress Summary:
Although this research was funded effective December 1, 1997, graduate students were not available to work on the project until September 1, 1998, when the entering class of Fall 1998 arrived. In effect, work on the project has just begun. The past few months have been spent training students in analytical methods, developing new analytical methods, and initiating adsorption equilibrium experiments on chemicals having a range of adsorption and biodegradation characteristics.Future Activities:
The research objectives will be achieved by an experimental program, complemented by mathematical modeling. SOCs over a broad range of characteristics will be studied from among the chemicals of current concern. Most experiments will involve two-component mixtures of a biodegradable and nonbiodegradable SOC. Typical GAC columns consist of three zones: exhausted GAC, mass transfer, and virgin GAC zones. All three are important to the success of biodegradation/adsorption systems in different ways. To discern the contribution of each zone, column experiments will be conducted with exhausted GAC zones only, mass transfer zones only, and complete GAC columns. Gas chromatography and radiochemical techniques with 14C-SOCs will be used to track the fate of both SOCs. Cometabolism is a technique for biodegrading SOCs that are, in a traditional sense, nonbiodegradable. Essentially no research has been conducted on cometabolism in GAC columns; therefore, preliminary experiments will be run to identify appropriate growth chemicals to stimulate cometabolism, before column experiments. Supporting experiments will measure desorption, displacement, and irreversible adsorption, which mainly affect bioregeneration of the GAC. Also, various equilibrium and kinetic parameters will be measured to support experimental design, data analysis, and modeling. Two existing biodegradation/adsorption models will be used: a simple equilibrium model and a sophisticated kinetic model. The models will provide a framework for synthesizing the experimental results into general observations on the applicability of biodegradation/adsorption systems for the treatment of mixtures.This research will fill a significant gap in our knowledge about GAC treatment, a gap that has economic, process performance, and health ramifications. Biodegradation/adsorption systems are potentially less costly, because the GAC service life can be longer than with adsorpt
Journal Articles:
No journal articles submitted with this report: View all 9 publications for this projectSupplemental Keywords:
water, adsorption, bioregeneration, bioremediation, innovative technology, synthetic organic chemicals., RFA, Scientific Discipline, Water, Ecological Risk Assessment, Environmental Chemistry, Wastewater, Bioremediation, Environmental Engineering, gas chromatography, cometabolism, kinetic studies, water quality, bioregeneration, granular activated carbon, biodegradation, fate and transport, water treatment, mathematical modelingRelevant Websites:
http://www.ce.utexas.edu/prof/speitel/home.html
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.