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Whether you're an analyst-of-all-trades at a municipality or a water quality specialist at a commercial laboratory, we have the information you need to succeed. Water Environment Laboratory Solutions focuses on day-to-day laboratory concerns, as well as discussing certification issues, staff management approaches, and new & revised analytical methods. |
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Vol. 15, No. 3 June/July 2008
FEATURES
New Detection-Limit Procedures: Is There A Clear Winner?
Charles R. Lytle, Jason Dahl, and Elizabeth Farkas
The City of Portland (Ore.) Water Pollution Control Laboratory (WPCL) maintains a keen interest in the national detection-limit discussions and decided to process a large set of historical and contemporary data for a single analyte (mercury) through one promulgated and three proposed detection-limit procedures. The first is the |
2007 Author/Subject Index
2006 Author/Subject Index
2005 Author/Subject Index
2004 Author/Subject Index | traditional MDL procedure promulgated at 40 CFR 136, Appendix B. The second is the lowest concentration minimum reporting level (LCMRL) procedure proposed by TSC. The third is the detection-limit–quantitation limit (DL–QL) procedure proposed by a technical work group of the FACDQ. The fourth is the critical level–detection limit (LC–LD) procedure proposed by Osborn and Georgian (2004).
The mercury wastewater data used in the WPCL comparison study were generated by using a modification of the microwave digestion method developed by CEM Corp. (Cary, N.C.) and promulgated at 40 CFR 136.3 (Table I-B) followed by quantitation by EPA Method 200.8 (inductively coupled plasma–mass spectroscopy, or ICP/MS). This method has been approved by EPA and the Oregon Department of Environmental Quality as an alternate test procedure. Method details were published in the August–September 2007 issue of Water Environment Laboratory Solutions.
Just as the procedures to calculate these values vary, so do the terms used to describe the results found.
Kill More Pathogens
New method relies on particle counts to monitor effluent quality
Mary Kay Anuskiewicz, Frank J. Loge, and Jeanne L. Darby
To produce reclaimed water that is suitable for most beneficial uses, treatment plants typically need to use filtration and disinfection processes. These processes ideally should work together to remove or inactivate enough particles to meet effluent limits.
The wastewater treatment industry needs to develop science-based operating strategies that enable filtration and disinfection processes to meet appropriate effluent standards while minimizing operating costs. Current techniques rely on such water quality constituents as total suspended solids and turbidity, which are not directly linked to the viable microorganism concentrations in effluent.
Another approach would be to use particle counts to monitor effluent quality. Particle characteristics, such as size, number, and porosity, vary depending on the biological treatment system (activated sludge reactor or facultative lagoon) and operating conditions (such as mean cell residence time) used. Particle characteristics also affect the removal and inactivation of the microorganisms occluded within the particles.
By evaluating the effect of particle-size distribution (PSD) on disinfection efficacy, design and process-control parameters can be developed that integrate the filtration and disinfection processes and collectively reduce the total number of viable microorganisms in reclaimed water.
NEWS
New England Laboratories Practice Readiness
Exercise helps labs improve integration, data sharing
In February, the U.S. Environmental Protection Agency (EPA) New England Regional Laboratory (North Chelmsford, Mass.) hosted a water contamination and biomonitoring exercise aimed at improving readiness if contamination from a chemical or biological agent should occur. The laboratory serves Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont, and 10 federally recognized tribes. Laboratories from all six states participated.
“The goal of this exercise was to provide not only confirmatory testing between one state and another but also [to] surge capacity,” said John Krueger, director of the Maine Center for Disease Control and Prevention Health and Environmental Testing Laboratory within the Maine Department of Health and Human Services.
The exercise was considered a success in solidifying cooperation among New England’s federal and state laboratories, as well as water utilities.
“Practicing the collaborative roles and mutual aid envisioned among regional laboratories that would be called upon to produce all of the analytic results in the event of a drinking water contamination incident is extremely important,” said Robert W. Varney, administrator of EPA’s New England regional office. “As we all know, you do not want to find out where our lab capabilities have run out during a real event.”
DEPARTMENTS
Web Notes
Reprints questions, and answers from WEF’s laboratory discussion boards.
Briefs
Coastal Areas Worldwide Suffer From Eutrophication and Hypoxia
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Click here to download
a PDF of the color images from the article "Size Doesn’t Matter"from the April-May 2008 issue. |
©2008 Water Environment Federation. All rights reserved. |
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