Grantee Research Project Results
2007 Progress Report: Development of a Universal Microbial Collector (UMC) for Enteric Pathogens in Water and its Application for the Detection of Contaminant Candidate List Organisms in Water
EPA Grant Number: R833009Title: Development of a Universal Microbial Collector (UMC) for Enteric Pathogens in Water and its Application for the Detection of Contaminant Candidate List Organisms in Water
Investigators: Bright, Kelly R. , Gerba, Charles P.
Institution: University of Arizona
EPA Project Officer: Aja, Hayley
Project Period: August 1, 2006 through July 31, 2009 (Extended to July 31, 2010)
Project Period Covered by this Report: August 1, 2006 through July 31, 2007
Project Amount: $466,817
RFA: Development and Evaluation of Innovative Approaches for the Quantitative Assessment of Pathogens in Drinking Water (2005) RFA Text | Recipients Lists
Research Category: Drinking Water , Water
Objective:
Since the development of pleated, positively charged filters for the concentration of viruses from large volumes of water in the 1980’s, there has been no significant improvement in concentration technology for viruses from water. Older methods are also being used for the concentration of protozoan parasites. No matter which method is used to detect enteric pathogens in water, a concentration step is essential. The ultimate goal of this project is to develop a simple, efficient, low cost method for the concentration of all classes of microorganisms from water that yields a concentrate of minimal volume and with minimal substances that would interfere with the microbial detection methodology.
Progress Summary:
During the first year of this project, we have focused primarily on the evaluation of two innovative nanofiber filtration technologies for the retention of microorganisms from water. The key to the success of our approach will be the efficient adsorption of the microbes onto nanofiber materials.
The first type of filter we have worked with is a proprietary charge-modified granular carbon nanofiber. The surface of this material has been modified to be highly positively charged. The enhanced retention of microorganisms on these filters is due to the combination of a large surface area (through the use of carbon nanofibers) and an enhanced cationic charge. The second filter type is comprised of nano alumina fibers. This material is also highly electropositive and has a large surface area, particularly in the pleated form.
The carbon nanofiber material was very effective at retaining multiple classes of microorganisms (> 99.99 %). This material was capable of retaining several types of phages and human enteric viruses of different sizes and surface properties (i.e. isoelectric points, hydrophobicity). The ability of the filters to capture microorganisms was not affected by high turbidity (30 NTU), high or low salt concentrations (up to 1,500 mg/L), pH (6.0 through 9.0), or high dissolved organic levels (10 mg/L).
For our initial evaluation of the alumina nanofiber filters, we used the bacteriophage MS-2 and Escherichia coli. The filters were very effective at retaining the virus at flow rates between 2 and 10 L per minute (76 to 99.96% retention). These filters were also found to be very effective at capturing the bacterium Escherichia coli (99.996% retention). These results are similar to those of more traditional filtering methods for viruses; however, these filters are available at a much lower cost.
We have also begun work on the evaluation of different elution methods for removing microorganisms from the filters. We have already been able to elute virus from the alumina nanofiber filters with efficiencies similar to existing methods.
Future Activities:
Our plans for the second year include the following:
- Continue work on the development of the elution protocols for both filter types. This will include testing of various eluents.
- Evaluate the method against CCL organisms and other waterborne pathogens using different water matrices.
- Compare the method to currently available concentration methods.
- Plan the third-year field study.
Journal Articles:
No journal articles submitted with this report: View all 4 publications for this projectSupplemental Keywords:
water, drinking water, viruses, protozoa, bacteria, monitoring, detection, occurrence, environmental sampling, nanofiber, filtration, carbon filters, pleated filters,, RFA, Scientific Discipline, Water, POLLUTANTS/TOXICS, Environmental Chemistry, Microorganisms, Drinking Water, Environmental Monitoring, viruses, contaminant candidate list, parasites, contaminant removal, drinking water contaminants, enteric viruses, drinking water treatment, activated carbon, aquatic organisms, drinking water monitoring, universal microbial collector, CCLProgress 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.