NBC 105 • Unit 310 min read★ High Exam Frequency
Air/Water/Noise Pollution, BOD/COD & 3R Solid Waste Management
Unit 3: Environmental Pollution & Waste Management • Environment and Ecology
👨🏫 Professor's Mental Model: Choking the Stream
BOD (Biochemical Oxygen Demand) ek river ke lungs ki tarah hai. Jab river me industrial kachra jata hai, toh bacteria use khane ke liye paani ka sara oxygen chus lete hain (High BOD). Result: fish aur jal-jeev saans na lene ke karan mar jaate hain (Eutrophication)!
Water Pollution: BOD, COD & Eutrophication
BOD: Amount of dissolved oxygen required by aerobic microorganisms to biologically decompose organic waste in water.
COD: Total oxygen required to chemically oxidize both organic and inorganic pollutants (COD > BOD).
Eutrophication: Excessive nutrient influx (N & P) causing algal bloom, blocking sunlight, and suffocating aquatic fauna.
Solid & E-Waste Management (3R Principle)
Reduce generation -> Reuse products -> Recycle materials.
Disposal: Sanitary Landfills, Incineration, Composting. E-waste hazards: toxic lead, mercury, cadmium leaching into groundwater.
🎯 University Exam Scoring Blueprint
- Define BOD and explain why clean drinking water has BOD < 1 mg/L while sewage has BOD > 300 mg/L.
- State the 3R waste hierarchy.
Top Viva Questions on Air/Water/Noise Pollution, BOD/COD & 3R Solid Waste Management
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