SOLID WASTE MANAGEMENT
Environment
Solid waste refers to unwanted and discarded solid materials generated from residential, industrial, commercial, and institutional activities. India generates nearly 62 million tonnes of municipal solid waste annually, projected to rise to 165 million tonnes by 2030.
Key Statistics:
- Collection efficiency in India: ~70% (vs nearly 100% in developed countries)
- Waste generated: 62 million tonnes/year
- Collected: 43 million tonnes
- Treated: 11.9 million tonnes
- Dumped in landfills: 31 million tonnes
- Only around 20% of collected waste is scientifically treated.
TREATMENT OF MUNICIPAL SOLID WASTE
1. Open Dumping and Landfills
- Controlled disposal of waste in designated land areas.
- Waste remains exposed, causing soil, air, and water pollution.
- Open dumps attract animals, encourage disease spread, and release toxic leachate.
2. Thermal Treatment
A. Incineration (Waste-to-Energy)
- Waste burned in presence of oxygen → CO₂, water vapor, ash + heat.
- Advantages: Reduction in waste volume, kills pathogens.
- Issues: High air pollution, toxic emissions, climate impact.
B. Pyrolysis
- Thermal degradation of organic material in absence of oxygen.
- Produces gas, oil, and carbon-rich char.
- Suitable for plastics, hazardous waste.
C. Plasma Arc Gasification (PAG)
- Uses electrical energy + high temperature to break waste into syngas and slag.
- No combustion; cleaner than incineration.
- Produces vitrified glass-like residue (environmentally safe).
- High cost but reduces landfill load.
3. Biological Treatment Methods
A. Bio-Gasification
- Anaerobic decomposition of biodegradable waste → methane-rich biogas.
- Useful for energy production.
B. Composting
- Decomposition of organic waste into nutrient-rich compost.
- Uses: Soil conditioner, fertilizer, landfill cover, erosion control.
C. Vermicomposting
- Decomposition using worms (red wigglers, white worms, earthworms).
- Produces high-quality compost.
D. Bioremediation
- Use of microbes to degrade contaminants.
- Includes:
• Bio-stimulation → enhancing native microbes.
• Bio-augmentation → adding selected microbes.
- Converts organic waste into soil-like material.
E. Biomining
- Uses sieving machines to extract soil, plastics, wood, metals from old dump sites.
- Helps reclaim land and recover materials.
SOLID WASTE MANAGEMENT RULES, 2016
Key Provisions:
- Applicable beyond municipal limits: includes railways, airports, SEZs, defence areas, religious sites.
- Mandatory source segregation into:
1. Wet waste
2. Dry waste
3. Domestic hazardous waste
- Responsibility on generators for segregation and user fee.
- Rag-picker integration into formal waste management.
- Strict prohibition on burning/ dumping in open areas.
- Bulk waste generators (hotels, markets, institutions) must treat waste on-site.
- New townships & housing societies must create in-house waste processing systems.
- Street vendors must keep separate bins.
- Developers of SEZs & industrial parks must allocate 5% area for waste recovery facilities.
- Producers of disposables must support waste management financially (EPR concept).
- Industries within 100 km of waste-to-energy plants must use 5% RDF.
- Waste with calorific value >1500 Kcal/kg cannot be landfilled—must be used for energy.
WASTE-TO-ENERGY (W2E) PLANTS
Two types:
1. Plants that burn unsegregated MSW.
2. Plants using RDF (Refuse Derived Fuel).
Refuse-derived fuel:
- Produced from combustible components of MSW (plastics, paper, textiles).
- Non-combustibles like glass removed.
Advantages:
- Reduces waste volume significantly.
- Produces electricity.
- Reduces burden on landfills.
- Can be profitable with proper technology.
Constraints:
- Technology still emerging in India.
- Heavy dependence on imports.
- Western technologies unsuitable for mixed Indian waste.
- High project costs.
- Poor segregation leads to plant inefficiency.
- ULBs lack finances, land allotment, and consistent supply chains.
- Pollution concerns around dioxins and furans.
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Subject: Environment
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