Question

What are flocs formed during the secondary of sewage?

Answer 1

Contamination removal from the waste water is very important for the cleanliness of rivers. To remove this contamination the government has organized a treatment programme known as sewage treatment.

Complete Answer:
Sewage which is also known as domestic municipal wastewater, is a category of wastewater which is produced by a community of people. It is characterized by rate of flow, physical condition, chemical and toxic constituents, and also its bacteriologic status. It is composed mostly of grey water that is from sinks, bathtubs, showers, dishwashers, and clothes washers, and blackwater which is from the water used to flush toilets, combined with the human waste that it flushes away soaps and detergents and the toilet paper.

Sewage generally travels from a building's plumbing moreover into a sewer that will carry it in another place, or into an onsite sewage facility of which there are many types. Whether it is combined with surface runoff in the sewer will depend on the sewer design that is sanitary sewer or combined sewer. The certainty is that most wastewater formed globally remains untreated which will cause extensive water pollution, particularly in low-income countries.
- Sewage treatment usually consists of three stages; they are known as primary, secondary and tertiary treatment.
- Flocs are fundamentally groups of bacteria which are in a sludge structure and are apprehended together with the use of slime.
- Flocs are very helpful in increasing the decomposition rate and are put in the ventilation tank while the secondary sewage treatment process is in effect.
- This results in the sewage BOD that is Biochemical Oxygen Demand falling by up to approximately 15 percent before being passed on to the settlement tanks.

Note: The sewage water after the secondary treatment is very clean enough to pass into the river. And also some further treatments are done to clean the water which the flocs cannot.