The device used for the aeration in the combined aerator is
Explanation: In combined aeration, both diffused air aeration and mechanical aeration take place using both diffuser plate and paddles.
The detention period of the Sheffield mechanical aeration tank is
Explanation: The detention period of a Sheffield mechanical aeration tank is 15 hours. Its return sludge is 15-20% of sewage flow.
The minimum detention period of combined aerator is
Explanation: The detention period of combined aerator lies between 3 to 4 hours and the minimum detention period is 3 hours.
The speed at which the bubbles are formed in the simplex aerator
Explanation: The cones, with spiral vanes rotates at a high speed of 60rpm that results in the formation of bubbles in a simplex aerator resulting in the aeration of sewage.
Dorroco aerator is a type of
Explanation: Dorroco aerator is a type of combined aerator which is efficient in comparison to diffused air and mechanical aerator.
Simplex aerator is a type of
Explanation: Simplex aerator is a type of mechanical aerator where a square or rectangular tank with a hopper bottom is used.
Which gas is produced in aerobic digestion of sludge?
Explanation: Carbon dioxide gas is produced in the aerobic digestion of sludge by the oxidation of organic matter by bacteria into CO2.
Which of the following process is not involved in the treatment of sludge?
Explanation: The process involved in the treatment of sludge are thickening, stabilization, dewatering and dying.
Which of the following is the final stage in the sludge treatment process?
Explanation: Drying of the sludge is the final stage in the sludge treatment process where the most stable form of sludge is obtained.
In which sludge treatment process, the organic solids are converted into more stable form?
Explanation: In the sludge digestion process, the organic solids are converted into more stable form. It makes the dewatering and drying process of sludge simpler.