UV Pilot Testing: Intensity Distributions and Hydrodynamics
The process behavior of ultraviolet (UV) disinfection has not been as well characterized as that of chlorine disinfection. As a result, UV system design is heavily dependent on pilot testing. Most UV pilot tests have been performed using relatively small-scale UV systems (e.g., Snider et al. 1991; N...
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Veröffentlicht in: | Journal of environmental engineering (New York, N.Y.) N.Y.), 1995-03, Vol.121 (3), p.258-262 |
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Sprache: | eng |
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Zusammenfassung: | The process behavior of ultraviolet (UV) disinfection has not been as well characterized as that of chlorine disinfection. As a result, UV system design is heavily dependent on pilot testing. Most UV pilot tests have been performed using relatively small-scale UV systems (e.g., Snider et al. 1991; Nieminski and Fenhaus 1991; Gross and Davis 1991; Maarschalkerweerd et al. 1990), probably for economic reasons. Small-scale UV pilot systems are typically operated at flow rates of 2 to 10 L/s; many of these systems have employed a channel with a 7.5 cm x 7.5 cm cross section. A notable exception was the work by Chrtek and Popp (1991) in which a relatively large-scale (Q approximately 40 L/s or 0.9 mgd) pilot study of UV disinfection was performed; channel dimensions were not listed for this work, but it is believed that a channel cross section of 61 cm x 147 cm was employed. Although small-scale pilot systems are useful for providing qualitative or semiquantitative information regarding UV disinfection performance at a given site, difficulties may be encountered in extrapolation to full-scale design due to nonlinear scaling of some important process characteristics. In particular, small-scale systems will not accurately simulate full-scale UV intensity distributions or hydrodynamics; these are two of the most important aspects of UV systems with respect to disinfection efficacy. The purpose of this technical note is to present the fundamental differences between small- and large-scale UV systems, particularly as they relate to pilot testing. Results of numerical simulations and field measurements on two large-scale pilot systems are used to illustrate the relative advantages of the large-scale approach in terms of intensity distributions and fluid-flow characteristics. |
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ISSN: | 0733-9372 1943-7870 |
DOI: | 10.1061/(ASCE)0733-9372(1995)121:3(258) |