Municipal Solid Waste Management

Waste‐Disposal Options

• Main methods: sanitary landfills, incineration (with or without energy recovery), ocean dumping (largely prohibited), and recycling/composting.
• Choice depends on cost, space availability, environmental impact, and public acceptance.

Landfills

• Most common disposal technique; engineered to isolate waste from groundwater and air.
• Problems: site shortages near cities, rising land prices, long‐distance hauling.
• Environmental risks: leachate, CH4CH_4 generation, long‐term monitoring costs.
• Tipping fees climbing toward $65−180\$65{-}180 per ton; makes alternatives more attractive.

Ocean Dumping

• Formerly accepted for sludge & dredge spoils; generated about 150,000150{,}000 tons (2017 data).
• Banned/strictly limited in many nations due to marine pollution and public outcry.

Incineration (Waste-to-Energy)

• Reduces waste volume by up to 90%90\% and mass by 75%75\%.
• Typical plant handles >1{,}000 t day−1^{-1}; construction ≈ $300 million\$300\,\text{million}.
• Pros: recovers heat/electricity, lowers landfill need.
• Cons: high capital, toxic air emissions, ash disposal, local opposition.

Shrinking the Waste Stream

• Source reduction (designing lighter, durable, reusable goods) is top priority.
• Extended producer responsibility & take-back laws shift disposal cost to manufacturers.

Recycling

• Current municipal recycling ≈ 15%15\% of waste; targets 25−50%25{-}50\% in many cities.
• Collection cost ≈ $35\$35 t−1^{-1} versus $65−180\$65{-}180 t−1^{-1} landfill/incineration fees.
• Markets fluctuate; PET, aluminum, office paper usually profitable.
• Benefits: conserves resources, saves energy (e.g., aluminum recycling cuts energy >90\%), reduces pollution and greenhouse gases.

Creating Incentives

• Pay-as-you-throw unit pricing: households charged per bag/bin, boosts diversion rates.
• Deposit–refund systems for bottles/cans raise return rates above 80%80\%.
• Government procurement & minimum-recycled-content rules stabilize markets.

Composting (Organic Waste)

• Converts food, yard, paper waste into nutrient-rich humus; can divert 25−30%25{-}30\% of municipal stream.
• Requires proper aeration, moisture, C:N ratio ∼30:1\sim30{:}1; complete in 2−62{-}6 months.
• Scales: backyard piles, curbside green-bin programs, large in-vessel systems.

Energy From Waste

• Anaerobic digestion of organics yields biogas (≈ 60%60\% CH4CH_4) usable for heat or power.
• Landfill gas capture offsets fossil fuels and cuts greenhouse emissions.

Key Numbers to Remember

• Average U.S. resident discards ∼2 000\sim2\,000 lb (≈900900 kg) solid waste per year.
• Incineration volume reduction: 80−90%80{-}90\%.
• Recycling energy savings: aluminum >90\%, paper 40−60%40{-}60\%, plastics 70−80%70{-}80\%.
• Compostable fraction in developing nations’ waste: up to 85%85\%.