With self cleansing velocity in sewers

 

(A) silting occurs at bottom

 

(B) neither silting nor scouring occurs at bottom

 

(C) both silting and scouring occur at bottom

 

(D) scouring occurs at bottom

Permanent hardness of water can be removed by

(A) adding alum

(B) adding chlorine

(C) boiling

(D) lime soda process

Which one of the following causes cumulative poisoning by water?

(A) lead

(B) iron

(C) barium

(D) manganese

Meyer's and Rohwer's formula are used to determine.

(A) evaporation

(B) average rainfall over a basin

(C) transpiration

(D) precipitation

Colorimetric method of testing water is to determine

(A) turbidity

(B) hardness

(C) chlorides

(D) pH value

The most common and universal coagulant used in water works is

(A) magnesium sulphate

(B) calcium sulphate

(C) chlorine

(D) aluminium sulphate

Rainwater of the locality which flows in sewer is called

(A) subsoil water

(B) storm water

(C) combined sewage

(D) sullage

Which one of the following is not surface water?

(A) from natural spring

(B) from natural lakes

(C) from reservoir storage

(D) from river diversion

A dam constructed to store water during floods and release is gradually later is known as

(A) rigid dam

(B) detention dam

(C) diversion dam

(D) storage dam

Vertical wells provided along the banks of a riverbed to draw ground water in dry season are known as

(A) artesian wells

(B) infiltration wells

(C) tubewells

(D) open wells

Which one is not the effect of presence of iron oxide in water

(A) causes toxic effect

(B) increases hardness

(C) increases corrosiveness

(D) causes red color