Question

A pressure difference of _____________ is applied to the vacuum floatation method to remove impurities from sewage.

(a) 0.5 atm

(b) 1 atm

(c) 1.5 atm

(d) 2 atm

This question was posed to me in an interview.

My query is from Grit Chambers, Tanks and Vacuum Floatation in section Unit Operations for Wastewater Treatment, Preliminary Treatment of Environmental Engineering

Answer 1

Right option is (b) 1 atm

The explanation: In the vacuum floatation method, pressure of 1 atm is applied in sewage followed by the vacuum that creates a pressure difference of 1 atm, resulting in the formation of bubbles that helps in the removal of large impurities in sewage.