Question
In which of the following wastewater treatment units is organic matter destroyed and stabilized by anaerobic bacteria ?
A. Sedimentation tank
B. Trickling filter
C. Oxidation pond
D. Septic tank
Answer: Option D – Septic tank
Explanation:
Septic tank:
Septic Tank is used in wastewater treatment in which a sudge is directly discharged and organic matterch destroyed and stabilized by anaerobic bacteria.
Activated sludge process:
The essential features of the activated sludge process are an aeration stage, solids-liquid separation following aeration, and a sludge recycle system.
Wastewater after primary treatment enters an aeration tank where the organic matter is brought into intimate contact with the sludge from the secondary clarifier.
It requires less space and requires less time for wastewater treatment.
It requires skilled supervision.
1)
Method:
Rotating biological contactor
Contact Mechanism:
Attached growth
Decomposition:
Aerobic
2)
Method:
Trickling filter
Contact Mechanism:
Attached growth
Decomposition:
Aerobic
3)
Method:
Activated sludge process
Contact Mechanism:
Suspended growth
Decomposition:
Aerobic
4)
Method:
Oxidation pond
Contact Mechanism:
Suspended growth
Decomposition:
Aerobic
5)
Method:
Septic tank
Contact Mechanism:
Suspended growth
Decomposition:
Anaerobic
6)
Method:
Imhoff tank
Contact Mechanism:
Suspended growth
Decomposition:
Anaerobic