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Optimization of Settling Tank Design to Remove Particles and Metals |
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| Authors: | Yingxia Li Joo-Hyon Kang Sim-Lin Lau Masoud Kayhanian Michael K Stenstrom |
| Affiliation: | 1Assistant Professor, School of Environment, Beijing Normal Univ., Beijing, 100875, P.R. China. 2Postdoctoral Associate, St. Anthony Falls Laboratory, Univ. of Minnesota, Minneapolis, MN 55414. 3Research Engineer, Dept. of Civil and Environmental Engineering, Univ. of California, Los Angeles, Los Angeles, CA 90095-1593. 4Associate Director, Center for Environmental and Water Resources Engineering, Dept. of Civil and Environmental Engineering, Univ. of California, Davis, Davis, CA 95616. 5Distinguished Professor, Dept. of Civil and Environmental Engineering, Univ. of California, Los Angeles, Los Angeles, CA 90095-1593. |
| Abstract: | Mass reduction rates of particles and metals were simulated for a two-compartment settling tank composed of a storage compartment and a continuous flow compartment. Particle-size distribution, rainfall, and flow data from 16 storm events measured at three highway sites were used. The volume ratio (i.e., ratio of surface areas for a given depth) between storage and continuous flow compartment was optimized for a given design storm size to maximize total mass reduction rates of particles and heavy metals. Measured settling velocity profiles of runoff samples were used in the simulation. Simulation results showed that in a given total design storm, larger storage compartment fractions (>0.95) enhanced the removal of smaller particles (2–104?μm) and particulate phase metals, and even a small fraction (<0.05) of continuous flow compartment effectively removed larger particles (104–1,000?μm). A volume fraction of 0.75 for the storage compartment is suggested to optimize annual reductions of particles and associated heavy metals. |
| Keywords: | Stormwater management Highways and roads Runoff Particle size distribution Best Management Practice Settling velocity Heavy metals Pollution Optimization |