Primary sludge is used for

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding Primary Sludge**: Primary sludge is a byproduct of the primary treatment process in sewage treatment. It consists of solid waste materials that settle out of sewage during the initial phase of treatment.

2. **Role in Sewage Treatment**: The primary treatment process involves the physical separation of solids from liquids in sewage. This is typically done using settling basins where heavier solids settle to the bottom, forming primary sludge.

3. **Usage of Primary Sludge**: The primary sludge is primarily used in the next stage of sewage treatment, which is the secondary treatment. In this stage, microorganisms are introduced to further break down the organic matter present in the sewage.

4. **Final Stages of Treatment**: After secondary treatment, the sewage undergoes tertiary treatment, where any remaining pathogens, viruses, and parasites are removed, making the water safe for reuse or recycling.

5. **Conclusion**: Therefore, primary sludge is used in the sewage treatment process, particularly in the secondary treatment phase, where it aids in the removal of organic material through microbial action.

**Final Answer**: Primary sludge is used for secondary treatment in sewage treatment processes.

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