The high rate sludge digestion tanks are used when the capacity of the tank is ____ million liters per day.
(a) 1
(b) 3
(c) 4
(d) 10
I had been asked this question in an online interview.
Query is from Digestion of Sludge, Sludge Digestion Tank topic in chapter Sewage Filtration and Activated Sludge Process of Environmental Engineering