Document Type : Original Article
Authors
1
Department of Water Science Engineering, Ahv.C., Islamic Azad University, Ahvaz, Iran.
2
Khuzestan Water and Power Organization, Ahvaz, Khuzestan, Iran
3
Department of Water Science Engineering, Ahv.C., Islamic Azad University, Ahvaz, Iran
10.22034/nawee.2026.584356.1225
Abstract
This study evaluates the hydraulic performance of a novel integrated pre-sedimentation and multilayer horizontal roughing filtration system for treating highly turbid surface water, developing dimensionless design relationships for process optimization. Using a laboratory-scale physical model featuring a 1 m stilling basin and a three-layer roughing filter (20, 10, and 2 mm media), 81 experimental runs were conducted. The experiments evaluated three filter lengths (260, 350, and 450 cm), three filtration velocities (0.20, 0.60, and 1.00 m h⁻¹), three operation times, and high influent turbidity (1500–2500 NTU). Input predictability was assessed using the Gamma Test. Results identified filter length as the dominant parameter, with a 260-to-450 cm increase improving turbidity removal efficiency by 9–10%, yielding maximum efficiencies exceeding 94% at 0.20 m h⁻¹. Filtration velocity exerted a secondary negative effect, while influent turbidity and operating time had limited influence. The Gamma Test confirmed a strong deterministic structure (Gamma = 0.0462, V-ratio = 0.1848). Overall, increasing the effective filter length significantly enhanced turbidity removal, demonstrating that filter length is a critical design parameter for treating highly turbid waters in resource-limited regions. However, these findings represent an experimental performance assessment of specific configurations, and absolute geometric optimization requires further investigations and techno-economic evaluation.
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