Biological process is carried out in which type of water treatment :

Options

A. Primary
B. Secondary
C. Tertiary
D. Both (1) & (2)

Answer

**Step-by-Step Solution:**

1. **Understanding Water Treatment Types**: Water treatment can be categorized into three main types: primary, secondary, and tertiary treatment. Each of these processes serves a different purpose in the treatment of wastewater.

2. **Identifying Primary Treatment**: The primary treatment involves physical processes such as sedimentation to remove large particles and debris from wastewater. This step does not involve biological processes.

3. **Identifying Secondary Treatment**: The secondary treatment is where biological processes come into play. This treatment uses microorganisms to break down organic matter in the wastewater. It primarily involves aerobic and anaerobic microorganisms.

4. **Role of Microorganisms**: In secondary treatment, aerobic microorganisms consume organic matter, reducing Biological Oxygen Demand (BOD), while anaerobic microorganisms help in further breaking down waste in the absence of oxygen.

5. **Conclusion**: Since the question specifically asks about the biological process in water treatment, the correct answer is the secondary treatment, as it is the stage where biological processes are actively utilized to treat wastewater.

**Final Answer**: The biological process is carried out in the secondary treatment of water treatment.

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