NEET PG High-Yield: Sewage Treatment
For NEET PG, focus on the process definitions and indicator metrics. Sewage treatment is a recurring topic in Social and Preventive Medicine (SPM).
Key Exam Points
| Concept | NEET PG “Must-Know” |
|---|---|
| BOD | Measures organic pollution. Standard test: 5 days at 20°C. |
| Activated Sludge | Most efficient secondary treatment method. Relies on aerobic bacteria. |
| Trickling Filter | Biofilm growth on stone media. Simple, less energy-intensive than activated sludge. |
| Primary Purpose | The goal is to reduce BOD to a level acceptable for discharge into receiving waters. |
High-Yield NEET PG Pearls:
- Sewage Sickness: A condition caused by excessive application of sewage to land, leading to soil pore blockage.
- Septic Tank Distance: Minimum 15 meters (50 feet) from a water well.
- Chlorination: Orthotolidine test used for residual chlorine; color change to yellow indicates presence of free chlorine.
- Effluent Standard: Always link BOD removal to the efficacy of the biological stage (secondary treatment).