Gravitational Settling Velocity Regimes for Heterodisperse Urban Drainage Particulate Matter
In: Journal of environmental engineering (New York, NY), Jg. 137 (2011), Heft 1, S. 15-27
Online
academicJournal
- print, 1 p.1/4
Zugriff:
Gravitational settling regimes, most commonly discrete (Type I) or flocculent (Type II) can be hindered (Type III) in unmaintained urban drainage appurtenances. In coastal zones or in areas with deicing salt applications, high salinity may influence particulate matter (PM) settling. This study examines settling of PM with a heterodisperse particle size distribution (PSD); typical of urban runoff. For Type I settling at low concentration (~0.1 g/L), Newton's and logarithmic matching models each predict measured settling velocity (Vs) for PM from 2-4,750 μm. For Type I Vs in runoff, PM diameter dominates the influence of PM density, fluid temperature and salinity parameter ranges. Integrating Type I Vsacross a common heterodisperse PSD for regulatory testing, a physically validated computational fluid dynamics model of a baffled hydrodynamic separator (HS) illustrates the influence of Vs parameters as PM diameter≫PM density > temperature≈salinity. Event-based PM separation by a screened HS loaded by unsteady flows and heterodisperse PSDs is predicted by overflow rate, and integrating measured (or validated Newton's Law) Vs, flow and PSD data. For Type II settling, Vs is a first-order function of PM concentration (1, 2, and 3 g/L); as well as time and settling depth. Type III V, is modeled as a power law function of PM concentration. Across the PSD tested, salinity up to 30 ppt does not have a significant (at p=0.05) role on Type I Vs. However, salinity is significant (at p=0.05) in Type II settling; as well as for Type III settling below 120 g/L. For all regimes, PM concentration, PSD heterodispersivity, and time dominate salinity or temperature influences.
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Gravitational Settling Velocity Regimes for Heterodisperse Urban Drainage Particulate Matter
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Autor/in / Beteiligte Person: | YING, G ; SANSALONE, J |
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Zeitschrift: | Journal of environmental engineering (New York, NY), Jg. 137 (2011), Heft 1, S. 15-27 |
Veröffentlichung: | Reston, VA: American Society of Civil Engineers, 2011 |
Medientyp: | academicJournal |
Umfang: | print, 1 p.1/4 |
ISSN: | 0733-9372 (print) |
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