Question

Where can we find rotating arm sprays in sewage treatment?

(a) Primary treatment

(b) Secondary treatment of trickling filter

(c) Secondary treatment of activated sludge process

(d) Secondary process of oxidation pool

This question was posed to me by my college director while I was bunking the class.

My query is from Effects and Control Measures of Marine Pollution in chapter Environmental Pollution of Energy Management

Answer 1

The correct option is (b) Secondary treatment of trickling filter

The explanation is: Rotating arm sprays water over rocks can be seen in secondary treatment of trickling filter. Rotating arm is followed by a circular bed of first size rocks and filter. That treated wastewater along with slim goes to secondary settling tank, which treats the water.