Non-aligned Treatment Technology

Completed Projects
Current Projects

Non-aligned or unaligned treatment technologies are technologies not associated with a specific vendor or manufacturer and consequently are not evaluated through the USEPA/NSF Environmental Technology Verification (ETV) Program. As a result these technologies may not be included as a viable treatment option because of a lack of a systemic evaluation from going through the ETV program. Biological filtration processes such as slow sand filtration, riverbank filtration, and biological activated carbon (BAC) filtration are examples of non-aligned treatment technologies.

Aeromonas Removal in Selected Water Treatment Processes

The genus Aeromonas is a group of bacteria ubiquitous in aquatic environments. They are considered as opportunistic waterborne pathogens responsible for acute gastroenteritis and wound infections in humans and animals. Aeromonas has been recognized as a primary human pathogen and listed as a microbiological contaminant on the EPA Drinking Water Contaminant Candidate List (CCL). Recently, the Unregulated Contaminant Monitoring Regulation(UCMR) has scheduled Aeromonas monitoring at 120 large and 180 small Public Water Systems (PWS, List 2) in 2003 (Federal Register, 40 CFR Part 141, March 7, 2002).

Due to the lack of accurate information on Aeromonas removal by water treatment facilities, it is difficult for a regulatory agency to recommend any specific treatment process or to impose a practical regulation on Aeromonas. To better understand the effectiveness of Aeromonas removal in existing water treatment facilities, a systematic study was conducted on the effectiveness of Aeromonas removal in each unit process at several utilities. Results from this project conducted primarily at the University of Tennessee, Knoxville will assist small water systems by identifying treatment processes that are capable of Aeromonas removal.

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Antibiotic Removal in Slow Sand Filtration

This research study focused on the removal of antibiotics in water treatment filtration, with emphasis on slow sand filtration or biological filtration processes. Representative antibiotic/antimicrobial compounds included the beta-lactam, sulfonamide, macrolide, and tetracycline classes of compounds. Contaminant removal efficiency studies will be performed at the pilot-scale slow sand filter research facility of the City of Salem, Oregon. Each of the antibiotic compounds was applied to ripened and unripened slow sand filters, and removal was assessed as a function of time, applied loading rate, and headloss accumulation. Pilot studies were performed on the tetracycline class of antimicrobials to determine the efficacy of a calcite-amended pretreatment roughing filter and crushed dolomite layer placed within the slow sand filter column to remediate these contaminants through complexation with cations dissolving from the limestone.

Equilibrium experiments were conducted to investigate antibiotic adsorption interactions on sand media, and degradation experiments will be performed on the supernatant, schmutzdecke, and sand column phases of the treatment process. Characterization of antibiotic removal were assessed throughout the pilot filter column considering source water organics concentrations, schmutzdecke age, and physical adsorption data to develop a mathematical model of antibiotic contaminant removal. This model may then be used to optimize slow sand filtration treatment processes and enhance antibiotic removal efficiencies of small and rural water treatment systems. The principal investigator for this project is Dr. Peter Nelson at Oregon State University.

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	Location of Geren Island water treatment facility near Stayton, Oregon (click on image to see larger).
	Aerial photo of Geren Island water treatment facility in December 1996 showing the SSF and normal Santiam river channel (click on image to see larger).
	Parallel roughing and slow sand filter systems installed at Geren Island (click on image to see larger).

 

Assessing the Role of a Schmutzdecke in Microbial Removals by Riverbank Filtration and Slow Sand Filtration

The microbial removal role of the interface between the overlaying water and the media bed whether in a slow sand filter (SSF) or a riverbank filtration (RBF) system has been a subject of much debate over the years. The results of this study confirmed that E. coli removals in slow-rate biological filters occur primarily at the interface and are related to schmutzdecke ripening state, empty bed contact time, biological activity, temperature, and protistan abundance. Using a suite of analyses characterizing the biofilm growing on the schmutzdecke, no connection was found between the preexisting extent of biological ripening and a filter's ability to recover from a scouring or scraping event that removed the schmutzdecke.

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Assessment of Riverbank Filtration as a Viable Pretreatment and Treatment Method

Riverbank filtration was evaluated for removals of microbial pathogens, particulates, organic precursors and other substances at 5 sites (Pembroke, NH; Jackson, NH; Milford,NH; Keene, NH; and Louisville, KY). River bank filtration was also assessed interms of itsability to perform as a viable treatment / pretreatment technology. Vaso Partinoudi worked on this project as a graduate student at UNH. She has presented her researchand results at the 2002 New England Water Works Associations Annual Conference and the National Water Research Institute 2nd International Riverbank Filtration Conference.

Presentations

Assessment of Riverbank Filtration as a Viable Treatment Process
V. Partinoudi M. R. Collins L. K. Brannaka

Assessment of the Microbial Removal Capabilities of Riverbank Filtration
V. Partinoudi M. R. Collins A. B. Margolin L. K. Brannaka

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Comparison of Slow Sand Filtration and Riverbank Filtration

The main goal of this project was to compare riverbank filtration (RBF) to slow sand filtration (SSF) in terms of particulate, organic precursors and microbiological removal capabilities expressed in log removal credits. The removal mechanisms of RBF and SSF are similar in both systems and rely on biological filtration processes involving biodegradation and bioadsorption.

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Enhanced Organic Precursor Removals by Gravel Roughing Filters

Treatment of highly colored source water is problematic for many small water systems, especially those systems which utilize biological filtration systems such as slow sand filtration. This project focused on enhancing slow sand filter (SSF) performance and, in particular, organic precursor removals using gravel roughing filters (GRF) with alum or ozone addition. Irfan Gehlen of Kerr Wood Leidal Associates (link to http://www.kwl.bc.ca) located in British Columbia, Canada is the principal investigator for this project. A series of pilot SSF and GRF columns were assembled in a variety of configurations to compare performance. The pilot systems were operated at the Glenmore Ellison Improvement District, British Columbia, where Mill Creek serves as a highly colored raw water source. Overall SSF removals and run times after selected pretreatment options were evaluated and compared. Anticipated outcomes of the completed study should assist small water systems, and extend the application of SSF to marginal raw water quality sources.

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Enhanced Particle Capture in Porous Media Using an Attachment Mediating Polymer (Cornell University)

The main goals of this project were to evaluate the potential use of a highly effective naturally occurring filter aid and to evaluate alternative sources of the ripening agent. The naturally occurring filter aid was obtained by extracting an acid soluble polymer from surface water seston. The filter aid enhances particle removal from raw source waters by modifying the filter media surface properties and appears to be responsible for most of the observed "ripening" of slow sand filters. Previous work demonstrated that the filter aid can be applied at the beginning of a filter run to effect high attachment efficiency.

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Evaluation of Fused Carbon Nanotube Technology for Drinking Water Treatment Applications

Fate and Transport of Radionuclides from Small Groundwater Treatment Systems

New England state environmental regulatory agencies are concerned with the fate, transport, and concentration of radionuclides discharged to waste disposal systems. With implementation of the EPA radionuclides rule, this problem will be further exacerbated and states and water systems will be forced to confront the issue. Vermont state regulators initiated a literature search to address needs at these systems and found studies conducted in Wisconsin and Illinois; however, this information is not a sufficient base for developing state disposal policies and recommendations. Without data, Vermont and other New England states cannot adequately address the issue. This research project assisted the New England states by systematically evaluating the fate and transport of radionuclides generated through small or individual water treatment systems that also utilize on-site disposal of the treatment brine. This project provided a preliminary assessment of the fate and transport of radionuclides from small groundwater treatment systems. This project was a joint EPA Headquarters and Region I project that was partially funded through an EPA Region I grant through the State of Vermont Department of Environmental Conservation. Dr. Tom Ballestero at the University of New Hampshire was the principal investigator.

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Presentation

Fate of Groundwater Radionuclides Moving Through Small Community Systems (pdf)
Thomas P. Ballestero

 

Assessing Temperature Influences on Slow Sand Filtration Treatment Performance

A concern that may limit slow sand filtration as a viable treatment option for many small communities is reduced treatment performance during colder temperatures. The major goal of this study is to systematically evaluate the treatment efficacy of slow sand filters under cold water conditions. Special emphasis will be given to determining whether slow sand filtration removal capabilities are reduced significantly from optimum summer conditions to more severe winter conditions as observed in the northern latitudes and mountainous regions.

Successful completion of this study will provide information to regulators, engineers and operators with regards to the effectiveness of biological filtration, specifically slow sand filters, to remove pathogenic microorganisms from cold water sources. Such information will be of assistance to decision-makers in determining whether to consider biological filtration as a viable treatment option for water systems exposed to severe winters. In addition, the completed study may also provide operators and designers with recommendations on how to maximize slow sand filter treatment performance during winter conditions experienced in northern New England.

Radioactive Contamination of Ion Exchange Resins used for Treatment of Radionuclides in Drinking Water

The objective of this project was to evaluate the potential of various cation exchange resins to become low level radioactive waste when used to remove radium from drinking water. The general premise of the proposed project was to treat water containing radionuclides or surrogate ions through ion exchange resins and collect samples of the resins over time. Results were used to develop theoretical curves for estimating the change in the radioactivity of the resins over time.

Presentation

Removing Radioactive Contamination from Ion Exchange Resins Used in Drinking Water Treatment
James McMahon, Dr. M. R. Collins

Assessing Pretreatment Needs of Small Water Systems

The principal goal of this proposed study is to survey source water pretreatment needs for small water systems. Special emphasis will be given to those source water qualities that are considered to be the most problematic for selected filtration systems satisfying EPA drinking Water regulations (e.g. Enhanced Surface Water Treatment Rule (SWTR), Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR), Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) and Disinfectants and Disinfection Byproducts Rule (D/DBP)). A common scenario for many water utilities is having to increase CT requirements (disinfectant concentration x contact time) to comply with the enhanced SWTR while still satisfying the requirements of the D/DBP Rule and especially the Stage 2 levels.

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Assessing Zero Valent Iron (ZVI) for Arsenic Removal

The overall goal of this project is to evaluate the influence of oxidizing conditions as quantified by redox potential (?e or Eh) on As removal by ZVI. The relationship between redox levels and the resulting impact of pH and competing anions (i.e., sulfates) on As removal by ZVI will also be assessed.

Presentations

Arsenic Removal by Zero Valent Iron: Influence of pH and Redox Potential
M. Le Roux & M.R. Collins

Arsenic Removal Using Rapid Sand Filter Media
C. Menard, D. Burt, M.R. Collins

 

Assessing Metal Oxide Coatings on Filter Media for Arsenic Removal

Powdered metal oxide particles will be coated on sand grains and diatomaceous earth filter media. These coated filter media will be evaluated for their ability to remove arsenic. These media will be evaluated using batch studies, continuous flow column studies, and a pilot study. The batch studies will quantify equilibrium capacities of the metal oxide coatings for arsenic. The column studies will be used to assess the removal of arsenic. The removal kinetics and influence of competing anions will also be assessed during the column phase. The coating of various filter media for enhancing filter performance will be of assistance to the waterworks industry by expanding contaminant removal capabilities of existing filtration systems.

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Pilot Study to Assess the Removal Capabilities of Riverbank Filtration

Most of the existing RBF treatment literature has rightly focused on the removal mechanisms associated with the surface water underground passage to the RBF extraction well. Pilot scale column studies provide an opportunity to assess removals due to the underground passage only (i.e. worst case conditions). The proposed research will focus on the removal of selected microorganisms and DBPs by RBF under specific conditions and without the contribution of groundwater. The removal of each of the compounds of interest will be assessed as a function of time, applied loading rate, and headloss accumulation.