Nov. 12, 2002 -- The U.S. Environmental Protection Agency (EPA) announced in the October 29, 2002, Federal Register that the Hach FilterTrak™ 10133 method, applied by the company's FilterTrak™ 660 Nephelometer, is approved for measuring turbidity for drinking water compliance monitoring.
This approval provides utilities the opportunity to both monitor and optimize their filtration processes using a single technology.
The optical design of the FilterTrak 660 Nephelometer applies a collimated, stable, light source that exhibits high beam density and a distinct wavelength. The unique design of the instrument allows full absorption of incident light and internal reflection, virtually eliminating stray light. Facilities applying this technology benefit from the highest accuracy at extremely low levels of turbidity.
This innovative design, approved by the USEPA for turbidity monitoring, sets the FilterTrak 660 Nephelometer apart from other on-line turbidimeters and makes possible several key performance features proven to be beneficial when optimizing filtration. The optical system of the Hach laser nephelometer is optimized to detect particles in the 0.1 to 0.5 micron range, allowing a size detection that rivals particle counters typically used in drinking water treatment. This feature provides operators with an early indication of filter deterioration.
The laser nephelometer also provides operators the best signal-to-noise ratio of any on-line nephelometer with a USEPA-accepted method. Using the interactive AquaTrend® Interface, operators can easily distinguish a baseline turbidity change as low as 0.5 mNTU (0.0005 NTU).
The operator noting this change can begin investigation to determine if it is a potential particulate event caused by process change. Conventional turbidity instruments are less sensitive and cannot discern an actual turbidity change from "instrument noise" until the change reaches 5 to 15 mNTU (0.005-0.015 NTU). (Note: 1 NTU = 1,000 mNTU.)
The laser nephelometer applies a defined view (volume analysis) for a distinct measure that allows quantitative assessment of variations in turbidity baseline dynamics. This baseline variability is easily expressed as RSD or Relative Standard Deviation for a defined set of measurement values. Applying this quantitative process control parameter can assist in the prediction of particle events, including breakthrough.
The FilterTrak 660 Nephelometer is the ideal day-to-day filtration management tool. It minimizes operator attention and maximizes on-line time by simplifying installation, operation, and maintenance. In addition to providing the most sensitive turbidity unit in the world, Hach Company also supplies operators with a simple method for complete, accurate, on-site calibration, using USEPA-accepted, prepared calibration standards, and on-demand calibration verification, using prepared and certified standards.
Hach Company provides complete solutions that allow the right testing and process control decisions, the highest quality water, and the peace of mind of all involved. For complete information and to order, contact Hach Company, P.O. Box 389, Loveland, Colorado, 80539, USA; visit www.hach.com; call 800.227.4224 in the USA and Canada; or call 970.669.3050 in all other areas.
