Question

In which type of water treatment is the biological process carried out?

• A. Primary treatment
• B. Secondary treatment
• C. Tertiary treatment
• D. None of the above

Answer 1

The correct option is B

Secondary treatment

The correct option is B:

Explanation of the correct option:

1. Sewage treatment is the process of removing waste and toxins from a society's, city's, or colony's wastewater.
2. This wastewater primarily consists of domestic sewage, with some industrial wastewater.
3. Various technologies, such as physical, chemical, and biological approaches, are employed in sewage treatment plants to remove contaminants and generate treated wastewater that is safe to discharge into the environment.
4. Secondary treatment is referred to as biological treatment because it is intended to significantly reduce the waste's biological components through aerobic biological processes.

Explanation of the incorrect option:

Option A:

1. The deposition of solid trash inside the water is a primary treatment for wastewater.
2. The wastewater is generally retained in a tank during initial treatment, where heavier solid waste falls to the bottom and lighter solid waste floats.
3. Primary treatment is also known as physical treatment.

Option C:

1. The third and final phase in the tertiary treatment of wastewater is the removal of phosphates and nitrates from the water supply.

Final answer: In the secondary treatment of water treatment the biological process is carried out.