AE-JE Foundation CE: Environment Quiz 6

The sewers are designed to maintain minimum velocity of flow

The dissolved oxygen in the waste water is reduced to zero and colour changes to black, then this type of sewage is called

Which of the following represents a very old lake which has almost become marshy?

Which of the following is the minimum limit (ppm) of the dissolved oxygen that must be in the water for survival of aquatic life?

Water discharged into a river mixes with the river water instantaneously and completely.

Waste water DO = 2 mg/l

Discharge rate = 1 m³/s

River water DO= 8 mg/l

Flow rate = 8 m³/s

Temperature = 20°C

Initial amount of DO in the mixture of water and river shall be:

Match List-I and List-II and select the correct answer using the code given below the lists:

List-I                                                  

(i) Sluice valve                              

(ii) Drain Valve                              

(iii) Air relief valve                                

(iv) Reflux valve                                   

List-II

1. Where submains branch off

2. In service pipe connection

3. At high elevation points

4. At low level reaches

Codes

What is the maximum distance between successive manholes in sewers of diameter more than 1.5 m?

Calculate the hydraulic radius of a sewer having dia 280 mm and d/D ratio 0.42

A sewer was laid at a gradient of 1 in 8765 is designed to flow half full. If the diameter of the sewer is 250 mm, calculate the velocity of flow in the sewer. Take manning’s coefficient to be 0.015

The minimum velocity which is required to be maintained in sewer pipes to avoid setting of solid particles is known as