Question

Which among the following quantity is considered while estimating the sewage quantity?

(a) Addition due to unaccounted private water supplies

(b) Addition due to infiltration

(c) Subtraction due to water losses

(d) Addition due to unaccounted private water supplies, infiltration and water losses

This question was addressed to me in quiz.

My question is based upon Schedule of Rates for Water Supply works topic in division Schedule of Rates Metric and F.B of Civil Engineering Drawing

Answer 1

Correct answer is (d) Addition due to unaccounted private water supplies, infiltration and water losses

Easy explanation: Addition due to infiltration-This is additional quantity due to groundwater seepage in to sewers through faulty joints or cracks formed in the pipes. The quantity of the water depends upon the height of the water table above the sewer invert level.

Addition due to unaccounted private water supplies- People using water supply from private wells, tube wells, etc. contribute to the wastewater generation more than the water supplied by municipal authority. Similarly, certain industries utilize their own source of water.

Subtraction due to water losses -The water loss, through leakage in water distribution system and house connections, does not reach consumers and hence, not appear as sewage.