Bioreactor landfills: experimental and field results

Area of Science:

• Environmental Engineering
• Waste Management Science
• Bioreactor Landfill Technology

Background:

• Bioreactor landfills enable active management by considering biological, chemical, and physical processes.
• Enhanced municipal solid waste (MSW) biodegradation reduces contaminant lifespan and long-term monitoring costs.

Purpose of the Study:

• To determine the effect of solid waste size, leachate recirculation, and nutrient balance on MSW biodegradation rates.
• To evaluate leachate recirculation in a full-scale bioreactor landfill.

Main Methods:

• Laboratory experiments investigating MSW particle size and biodegradation.
• Full-scale field study involving 8 years of leachate recirculation via infiltration lagoons.
• Monitoring of leachate pH, chloride concentration, and organic load (BOD, COD).

Main Results:

• Smaller MSW particle size significantly increased biodegradation rates.
• Leachate recirculation led to a shift in leachate pH from acidic to neutral (7-8) within 2 years.
• Observed decreasing trends in biological oxygen demand (BOD) and chemical oxygen demand (COD), indicating reduced organic load.
• Enhanced waste subsidence and decomposition resulted in recovery of landfill airspace.

Conclusions:

• Optimizing MSW particle size and implementing leachate recirculation are effective strategies for accelerating bioreactor landfill processes.
• Leachate recirculation promotes waste stabilization, reduces environmental impact, and improves landfill operational efficiency.
• Bioreactor landfill technology offers a sustainable approach to waste management with reduced long-term liabilities.