Effluent means

Options

A. Water remaining under the primary sludge .
B. Solid compunds of the sedimentation
C. Water remaning over the primary sludge
D. Flocs forms from the primary sludge

Answer

### Step-by-Step Solution:

1. **Understanding the Context**: The term "effluent" is often used in the context of wastewater treatment, particularly in the treatment of sewage. It is important to understand what happens during the sewage treatment process.

2. **Sewage Treatment Process**: In sewage treatment, there are several stages, including primary treatment, where solids are removed from the wastewater. This involves processes like filtration and sedimentation.

3. **Primary Treatment**: During primary treatment, the solid waste settles at the bottom, forming what is known as primary sludge. The liquid that remains above this sludge is referred to as the effluent.

4. **Analyzing the Options**:
- **Option 1**: "Water remaining under the primary sludge." This is incorrect because the effluent is above the sludge, not below it.
- **Option 2**: "Solid compounds of sedimentation." This is incorrect as effluent refers to liquid, not solids.
- **Option 3**: "Water remaining over the primary sludge." This is correct because it accurately describes the effluent.
- **Option 4**: "Phlox formed from the primary sludge." This is incorrect as phlox refers to a structure formed by microbes during secondary treatment, not effluent.

5. **Conclusion**: Based on the analysis of the options, the correct definition of "effluent" is the water that remains above the primary sludge after the primary treatment of sewage.

### Final Answer:
Effluent means the water remaining over the primary sludge after sewage treatment.

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