Describe how do ‘flocs’ and ‘activated sludge’ help in sewage treatment.

Solution

Roles of ‘flocs’ and ‘activated sludge’ in sewage treatment are as follows: Flocs These are masses of bacteria held together by slime and fungal filaments to form mesh-like structures. Flocs are used during the secondary sewage treatment in the aeration tank to increase the rate of decomposition. The microbes digest a lot of organic matter, converting it into microbial biomass and releasing a lot of minerals. As a result, BOD of the sewage reduces. As the BOD of waste is reduced to 10-15% of raw sewage, it is passed into settling tanks. In these tanks, flocs are allowed to undergo sedimentation. Activated Sludge The sediment of settling tank is called activated sludge. A part of it is used as inoculum in aeration tanks. The remaining part is passed into a large tank called anaerobic sludge digester. In these tanks, anaerobic microbes are present that digest the organic mass as well as aerobic microbes of activated sludge. The remaining sludge is used as manure or compost.

Some More Questions From Environmental Issues Chapter

For Daily Free Study Material Join wiredfaculty

Environmental Issues

Describe how do ‘flocs’ and ‘activated sludge’ help in sewage treatment.

Some More Questions From Environmental Issues Chapter

Ozone depletion will cause :

The meaning of BOD is :

Which of the following pollutants is not produced by exhaust of motor vehicles ?

What is the term for the inflammation of cornea due to high absorption of UV-B radiation :

Smog is a mixture of :

WHO’s recommendations about the industrial noise limit is of :

Which of the atmospheric layer contains ozone layer ?

The amount of dissolved oxygen required by the microorganisms to degrade the organic wastes present in water is called ?

The cause of acid rain is :

Which one of the following causes ozone depletion ?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Phone Number

Email Address

Location