Hotel Service Unit 10 Q7 Quiz

Correct Answer:
B) Air is bubbled through the sewage to provide oxygen to aerobic bacteria, which break down organic matter

Explanation:
In the secondary treatment stage, biological processes occur. Aerobic bacteria are provided with oxygen (often through aeration) to break down organic matter, reducing the biological load of the sewage.

Correct Answer:
B) To further purify the sewage through filtration or disinfection, making the water suitable for discharge

Explanation:
The tertiary treatment stage involves additional purification methods, such as filtration or disinfection (e.g., using chlorine or UV light), to ensure that the treated water meets environmental standards for safe discharge.

Correct Answer:
A) Primary treatment → Secondary treatment → Tertiary treatment

Explanation:
The flow of sewage through a biological sewage treatment plant follows a structured process:

• First, primary treatment removes large solids.
• Next, secondary treatment uses biological processes to break down organic matter.
• Finally, tertiary treatment further purifies the water before it is discharged.

Correct Answer:
B) The stage where solid waste is mechanically separated from the liquid sewage

Explanation:
During the primary treatment stage, large solids and debris are mechanically separated from the liquid. This prevents clogs and prepares the sewage for further biological treatment in the next stages.

Correct Answer:
A) Primary treatment, secondary treatment, and tertiary treatment

Explanation:
The three main stages of a biological sewage treatment plant are:

• Primary treatment, where large solids are separated from the liquid.
• Secondary treatment, where biological processes (aerobic or anaerobic) break down organic matter.
• Tertiary treatment, where additional filtration or disinfection is applied to further clean the water.