『Abstract
This study examined the granulometry of non-colloidal particulate
matter (PM) from four urban transportation land use catchments
(source areas) in Baton Rough, Little Rock, North Little Rock,
and New Orleans. Particle gradations ranging from 1 to greater
than 10,000μm were separated into dissolved (less than 1 μm),
suspended (1-25 μm), settleable (25-75 μm), and sediment (75-4750
μm) fractions. In Baton Rough, the primary size, results indicate
a suspended mass-based d50m of 10.8, 5.0
μm [mean (x（頭に-）), standard deviation (s)],
a particle density (ρs) of 2.40, 0.19 g/cm3
based on 12 events with complete runoff volume capture. On an
event-basis, the suspended fraction ranged from 5-25％ of the entire
gradation mass and correlated to turbidity. The Baton Rough d50m excluding grit-size material from all events
was 356, 69μm as compared to 421, 219μm for accumulated PM including
grit from all sites. Size gradations were successfully modeled
with a gamma distribution. Particle density generally varied from
2.1 to 2.6 g/cm3 across gradations. While specific
surface area generally increased with decreasing particle size,
over 50％ of total surface area was associated with gradations
greater than 250μm. The point of zero charge (pzc-pH) ranges from
7.5 to 9 for settleable and sediment fractions. Results from these
sites support published results for fully captured rainfall-runoff
events at a Cincinnati site of the same land use, and provide
properties/indices for monitoring, regulatory guidance, treatability
studies, source control, and design of in situ unit operations
targeting particle separation mechanisms.
L\Keywords: Urban runoff; Particulate matter; Particle size gradation;
Granulometry; Surface area; Unit operation; BMP』
1. Introduction
2. Objectives
3. Methodology
3.1. Catchment characteristics
3.2. Sample collection
3.3. PM fractionation
3.4. Imhoff Cone protocol
3.5. Mechanical sieve analysis (Settleable and sediment fractions)
3.6. Density, surface area and surface charge determination
4. Results and analysis
4.1. Differentiation of PM fractions
4.2. Granulometry of the suspended fraction
4.3. Granulometry of settleable and sediment fractions
4.4. Mass-based particle size distribution (PSDs) results
4.5. Physical and chemical properties of rainfall-runoff PM
5. Discussion
6. Conclusions
Nomenclature
Acknowledgements
References