Grantee Research Project Results
2002 Progress Report: Study of Particle and Pathogen Removal During Bank Filtration of River Waters
EPA Grant Number: R829011Title: Study of Particle and Pathogen Removal During Bank Filtration of River Waters
Investigators: Bouwer, Edward J. , Schwab, Kellogg J. , O'Melia, Charles R. , LeChevallier, Mark W. , Aboytes, Ramon
Institution: The Johns Hopkins University
EPA Project Officer: Page, Angela
Project Period: August 24, 2001 through August 23, 2004 (Extended to August 23, 2005)
Project Period Covered by this Report: August 24, 2001 through August 23, 2002
Project Amount: $536,316
RFA: Drinking Water (2000) RFA Text | Recipients Lists
Research Category: Drinking Water , Water
Objective:
The objectives of the research project are to: (1) evaluate the merits of riverbank filtration (RBF) for removing/controlling pathogens in drinking water supplies; (2) establish the merits of using particle removal, Clostridium, and other potential water quality indicator parameters as surrogates for pathogen removal; and (3) quantify the removal mechanisms so that appropriate treatment credits can be established for pathogen removal in RBF systems. RBF is a process that subjects river water to ground passage prior to its use as a drinking water source. Experience with RBF in Europe, and more recently in the United States, has demonstrated significant improvements in raw water quality, including removal of natural organic matter, biodegradable compounds, pesticides, microbes, and other water quality contaminants. However, little is known about the extent to which RBF may serve to reliably remove Giardia, Cryptosporidium, and other pathogens (e.g., bacteria and viruses) from river water.
Progress Summary:
This research consists of: (1) field studies to document actual changes in pathogen and particle concentrations from rivers of similar source quality in the context of variations in subsurface travel distances, pumping rates, season, porous medium properties, and residence times; and (2) parallel laboratory column studies with aquifer media to provide insights into process mechanisms so that reliable treatment credits for pathogen removal can be established. A summary of the research tasks that were either initiated and/or completed during the current reporting period (August 2001-August 2002) is provided below:
(1) Field monitoring was implemented at the three study sites (Indiana-American Water Company on the Ohio River at Jeffersonville, IN; Indiana-American Water Company on the Wabash River at Terre Haute, IN; and Missouri-American Water Company on the Missouri River at Parkville, MO) for various microorganisms and other water quality parameters. Monthly data collected at the study sites between January and July 2002, indicated no breakthrough of selected microorganisms in the well waters. Specifically, river waters had frequent positive detects of bacteria (Bacillus and Clostridium) and bacteriophage (MS2 and X174). Waterborne protozoan parasites Cryptosporidium and Giardia were detected in raw surface water samples from all three rivers. The highest concentration of Cryptosporidium oocysts was found in a positive sample from the Ohio River (0.3 oocysts/L) using U.S. Environmental Protection Agency Method 1623. All well water samples tested negative for all microorganisms tested, with the exception of Bacillus, which was detected in a few raw well water samples.
(2) Methods for pathogen detection and stock production for the laboratory column experiments were developed.
(3) A small test column was constructed and packed with filter sand to provide practice in column packing and operation and assist in the design of the actual riverbank media columns. NaBr and bacteriophage MS2 solutions were passed through the column separately. Breakthrough of MS2 was similar to that of the bromide tracer, but was reached earlier than the tracer, possibly the result of MS2 being excluded from smaller pores. No overall removal of MS2 was observed in the test column.
(4) An initial sampling trip to collect aquifer sediment from the Potomac River in western Maryland has provided insight into the collection of both fine- and coarse-grained material from the aquifer. Sampling was conducted using a vibracoring device that has been used extensively by researchers at Johns Hopkins University to take sediment cores for laboratory analysis. The vibracorer works by vibrating a 3-inch diameter aluminum core sleeve that is simultaneously pushed into the ground by hand. Samples were taken by wading several feet into the river and coring the river bottom. The vibracorer could not penetrate a layer of coarse sand and gravel located beneath a fine-grained sediment layer. Therefore, several small cores of the fine-grained upper layer were taken for initial soil characterization.
Future Activities:
Coarse-grained aquifer material will be collected during an upcoming sampling trip to the Potomac River in western Maryland using a hand shovel. Columns on the order of 1 meter in length then will be constructed using the fine-grained and coarse-grained material in different proportions to observe the effect of the grain size distribution on the efficiency of riverbank filtration at removing the various microorganisms. The columns then will be challenged with mixtures of particles and microorganisms under different solution chemistries. The mixtures will include river waters collected from the three study sites. Physical and chemical perturbation studies will be conducted by varying the flow rate, ionic strength, pH, and pathogen concentrations of the feed solutions to simulate periods of rainfall and increased pumping. Field monitoring of the study sites will continue, providing a comprehensive database of the efficiency of riverbank filtration for these systems.
Journal Articles:
No journal articles submitted with this report: View all 13 publications for this projectSupplemental Keywords:
pumping, wells, treatment, regulations, water quality, microorganisms., RFA, Scientific Discipline, PHYSICAL ASPECTS, Health, Water, Environmental Chemistry, Health Risk Assessment, Environmental Microbiology, Risk Assessments, Environmental Monitoring, Physical Processes, Drinking Water, clostridium, groundwater disinfection, microbial contamination, pathogens, river water , monitoring, ecological risk assessment, disinfection byproducts, aquifer characteristics, microbiological organisms, water quality parameters, waterborne disease, exposure and effects, disinfection byproducts (DPBs), exposure, cryptosporidium , drinking water distribution system, particle counts, treatment, microbial risk management, human exposure, water quality, drinking water contaminants, drinking water treatment, Giardia, water treatment, riverbank filtrationProgress 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.