GATE CE 2020 Set 2 — Question 35
Go beyond PYQs with Success TrackerAI-powered personalised practice and doubt support. Unlimited practice on eligible plans; AI usage limits apply.NAT+1 / -0MediumPrimary SedimentationWastewater Treatment ProcessesEnvironmental Engineering
Environmental Engineering → Wastewater Treatment Processes → Primary Sedimentation
Last updated
Question
Two identically sized primary settling tanks receive water for Type-I settling (discrete particles in dilute suspension) under laminar flow conditions. The Surface Overflow Rate (SOR) maintained in the two tanks are and . The lowest diameters of the particles, which shall be settled out completely under SORs of and are designated as and , respectively. The ratio, (round off to two decimal places), is ________.
Correct answer
1.4 to 1.42
Solution
For Type-I settling under laminar flow conditions, the settling velocity is given by Stokes' Law: . For 100% removal, the settling velocity must be at least equal to the Surface Overflow Rate (SOR). The lowest diameter that is completely removed corresponds to . Thus, , which implies . The ratio is calculated as:Rounding to two decimal places, we get 1.41.
Continue learning with Success Tracker
A step still unclear? Work through it with support
Use Success Tracker to ask about the reasoning, then try another GATE CE question to check your understanding.
AI-powered practice· Unlimited practice on eligible plans
- PYQs with solutions
- Attempt available previous-year questions, then compare your reasoning with the worked solution. Coverage varies by stream.
- Practice that adapts
- Choose a topic, work on weaker areas and bookmark questions to revisit. Your attempts feed your progress tracking.
- AI doubt support
- Ask follow-up questions about a step or concept while practising, instead of stopping at the final answer.
Unlimited practice is available on eligible plans. Free practice and AI usage have limits; check the current plan allowances before choosing.
This page stays readable without an account. AI responses can be wrong; check them against the solution and source material.
More questions on Wastewater Treatment Processes
2026 Set 1 Q21A rapid sand filter bed of depth m has % porosity during service cycle. It is…2026 Set 1 Q22The settling velocity of inorganic particles in the sedimentation tank of a water treatment plant…2026 Set 1 Q25Which of the following components is/are NOT removed in the secondary treatment of sewage?2026 Set 2 Q27Column I presents common air pollutants, and column II presents treatment technologies commonly…2026 Set 2 Q28One-third of the solid matter in a sludge containing water is composed of fixed mineral…