Question

Consider the following treatment steps in a conventional wastewater treatment plant:
1. Loading and sedimentation
2. Chlorination or ozonization
3. Aeration
4. Filtration
The correct sequence of these steps is

• A. 2-1-4-3
• B. 1-4-3-2
• C. 3-1-4-2
• D. 1-2-4-3

Answer 1

The correct option is B 1-4-3-2

Step 1: Loading and sedimentation:
Sedimentation is setting down of a substance generally in a liquid medium whereas loading is a process of making sedimentation faster.
Step 2: Filtration:
The water after sedimentation still contains some lighter impurities which are removed by filtration.
Step 3: Aeration:
Air under pressure is then blown into the filtered water. This process is called aeration.
Step 4: Chlorination or ozonisation:
Water is then passed into a chlorine tank where it is treated with chlorine to kill the germs present in it.