Some Proposals for the Design Methodology of Two-Tier Sedimentation Tanks
DOI:
https://doi.org/10.54338/27382656-2026.11-01Keywords:
two-tier sedimentation tank, sedimentation trough, flow section, design depth, detention time, suspended solids, hydraulic sizeAbstract
The conventional design methodology for two-tier sedimentation tanks has several limitations: some design parameters are assumed, while others, in our opinion, should be calculated. This particularly concerns the depth of the flow section of the sedimentation tank ( ) and the detention time ( ). According to the proposed calculation methodology, achieving a clarification efficiency of
40–65% in two-story settling tanks requires significantly shorter settling times than the currently adopted design values of 5400 s (or 3600 s under low-flow conditions). A clarification efficiency of 42.9% can be achieved with a settling time of only 1630 s. By maintaining a settling-zone depth of 1.2–2.5 m, the methodology enables independent determination of the depths of the cylindrical and conical sections. This design promotes laminar wastewater flow, enhances suspended-solids sedimentation, and reduces both settling-zone and overall tank dimensions while maintaining the required clarification efficiency.
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Copyright (c) 2026 Varuzhan Shamyan, Albert Margaryan, Aram Sahakyan, Vahan Kobelyan, Mohamed Gabr, Armenuhi Minasyan

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