Primary Treatment of Sewage

The primary treatment of sewage is the first stage of the sewage treatment process. It involves the physical removal of solid and organic materials from the wastewater. The correct answer is option 'C' because primary treatment includes the removal of organic materials. Let's discuss the primary treatment of sewage in detail:

Removal of Floating Materials
- The first step in the primary treatment of sewage is the removal of floating materials such as leaves, paper, plastics, and other debris.
- This is done by passing the wastewater through a screen or a mechanical bar screen that filters out large objects.
- The screened wastewater then flows into a grit chamber where heavy materials such as sand and grit settle to the bottom.

Removal of Organic Materials
- The next step in the primary treatment of sewage is the removal of organic materials such as human waste, food waste, and other biodegradable matter.
- This is done by allowing the wastewater to settle in a primary sedimentation tank where the solid particles settle to the bottom and form sludge.
- The sludge is then removed and treated separately.
- The treated wastewater is then discharged into the environment or sent for further treatment.

Conclusion
In conclusion, the primary treatment of sewage involves the physical removal of solid and organic materials from the wastewater. It includes the removal of floating materials, sand and grit, and organic materials such as human waste and food waste. The treated wastewater can then be discharged into the environment or sent for further treatment.