GATE 2017 CE (CE2) – Question 62
A plant treats 1000 m³/day. An overflow rate of 20 m/day satisfactorily removes discrete suspended particles. For water depth 3 m, the required circular settling-tank diameter, to the nearest integer, is ______ m.
Practise this question in The GATE Grind →
Show answer and explanation
Correct answer: 8 to 8
Explanation
Required settling area is $A=Q/v_o=1000/20=50$ m². Hence $D=\sqrt{4A/\pi}=\sqrt{200/\pi}=7.97885$ m, rounded to 8 m. The stated depth affects detention volume but not this surface-area criterion.