--- title: "Solid waste management system and techniques" subject: "Environment and Pollution Control" chapter: 5 key: "semester_7/environment_and_pollution_control:solid-waste-management-techniques" source: https://www.bctengineer.com/q/semester_7/environment_and_pollution_control/solid-waste-management-techniques site: BCT Engineering --- # Solid waste management system and techniques Environment and Pollution Control · Chapter 5: Solid waste - Asked in: year not given, 8 marks - Video: [SWM-1.4-SOLID WASTE MANAGEMENT TECHNICQUES](https://www.youtube.com/watch?v=0D6FeyG64Wk) — RUTVA jadhav - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/environment_and_pollution_control/solid-waste-management-techniques - Whole chapter: https://www.bctengineer.com/md/semester_7/environment_and_pollution_control/chapter-5 ## Question Describe the functional elements of a municipal solid waste management system and explain composting, incineration and sanitary landfill as treatment and disposal techniques. Mention the waste management hierarchy. ## Short answer Functional elements: generation, on-site storage, collection, transfer, treatment, disposal. Hierarchy: reduce, reuse, recycle, treatment, landfill. Composting: aerobic decomposition of organics, windrow/pit, C/N 25–30, 4–8 weeks. Incineration: 850–1100°C reduces volume ~90%, needs high calorific waste and emission control. Sanitary landfill: layered and compacted with daily soil cover, liner, leachate collection, gas vents. ## Answer #### Functional elements 1. **Generation and source reduction** (houses, markets, industries). 2. **On-site handling and storage** (bins, segregation at source). 3. **Collection** (door to door, community bins). 4. **Transfer and transport** (compactor trucks, transfer stations). 5. **Processing and treatment** (recycling, composting, incineration). 6. **Final disposal** (sanitary landfill). #### Waste hierarchy (3R) ```text Reduce (most preferred) | Reuse | Recycle / recover | Treatment (compost, energy) | Landfill (least preferred) ``` #### Composting Aerobic biological decomposition of organic waste by microorganisms into stable, humus-like compost. Methods: windrow, pit, aerated static pile and vermicomposting (using earthworms). Conditions: C/N 25-30, moisture 50-60%, temperature 55-65 $^\circ$C, and enough air. Time: 4-8 weeks. The product is a soil conditioner. It suits the high organic fraction of waste in Nepal. #### Incineration Controlled burning of waste at 850-1100 $^\circ$C to reduce volume by about 90% and mass by about 70%. The heat can generate steam or electricity. It needs waste of high calorific value and low moisture, and air pollution control (scrubbers, bag filters) for dioxins, fly ash and acid gases. It is costly, so it is used mostly for medical and hazardous waste. #### Sanitary landfill Engineered disposal of waste in layers, compacted and covered each day with soil (15 cm). Features: site selection (away from water sources), liner (clay/HDPE), leachate collection and treatment, gas vents (methane collection), final cap and monitoring. Leachate and methane are the main problems; the land can be reused after closure. Other methods: open dumping (bad practice), pyrolysis, and biogas digestion of organic waste. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. In the waste management hierarchy, which is most preferred and which is least preferred? A. Landfill most, reduce least B. Recycle most, reuse least C. Reduce most, landfill least D. Incineration most, composting least Answer: C. The hierarchy runs Reduce, Reuse, Recycle, Treatment, then Landfill as the least preferred option. (Key point: Waste hierarchy) 2. Which set of conditions suits aerobic composting? A. C/N 25-30, moisture 50-60%, 55-65 degC, enough air B. C/N 5, moisture 5%, 20 degC, no air C. C/N 100, saturated moisture, 5 degC, no air D. C/N 25-30, no air, 850-1100 degC Answer: A. Composting is aerobic and needs C/N of 25-30, 50-60% moisture, 55-65 degC and air supply. (Key point: Composting conditions) 3. Why is incineration used mostly for medical and hazardous waste rather than general MSW in Nepal? A. It increases the waste volume B. It needs high calorific, low-moisture waste, is costly and needs air pollution control C. It works only below 100 degC D. It produces compost as a by-product Answer: B. Incineration needs dry, high-calorific waste and costly scrubbers/filters for dioxins, fly ash and acid gases, so it is limited to special wastes. (Key point: Incineration requirements) 4. What distinguishes a sanitary landfill from open dumping? A. Waste is simply piled and left B. Waste is compacted in layers, covered daily with soil, with liner, leachate collection and gas vents C. Waste is burnt in the open D. Waste is spread on farmland Answer: B. A sanitary landfill is engineered: daily soil cover (about 15 cm), liner, leachate collection and treatment, gas vents and monitoring. (Key point: Sanitary landfill features) ## Related in Environment and Pollution Control - [Treatment and disposal of hazardous waste](https://www.bctengineer.com/question.md?key=semester_7%2Fenvironment_and_pollution_control%3Ahazardous-waste-management-techniques) — Environment and Pollution Control, chapter 5 - [Physical and chemical characteristics of solid waste](https://www.bctengineer.com/question.md?key=semester_7%2Fenvironment_and_pollution_control%3Asolid-waste-characteristics) — Environment and Pollution Control, chapter 5 - [Municipal wastewater treatment plant](https://www.bctengineer.com/question.md?key=semester_7%2Fenvironment_and_pollution_control%3Amunicipal-wastewater-treatment-plant) — Environment and Pollution Control, chapter 4 - [Landfill volume and area calculation](https://www.bctengineer.com/question.md?key=semester_7%2Fenvironment_and_pollution_control%3Alandfill-area-volume-numerical) — Environment and Pollution Control, chapter 5 ## Related in other subjects - [Methods of solid waste disposal](https://www.bctengineer.com/question.md?key=semester_6%2Fsanitary_engineering%3Asolid-waste-disposal-methods) — Sanitary Engineering, chapter 10, asked 2× - [Sanitary landfill: merits and demerits](https://www.bctengineer.com/question.md?key=semester_6%2Fsanitary_engineering%3Asanitary-landfill-merits) — Sanitary Engineering, chapter 10, asked 4× - [Composting: methods, merits, demerits](https://www.bctengineer.com/question.md?key=semester_6%2Fsanitary_engineering%3Asolid-waste-composting) — Sanitary Engineering, chapter 10, asked 5× - [Open dumping and sanitary landfill](https://www.bctengineer.com/question.md?key=semester_6%2Fsanitary_engineering%3Aopen-dumping-vs-landfill) — Sanitary Engineering, chapter 10, asked 2×