Numerical simulation to optimize passive aeration strategy for semi-aerobic landfill

Area of Science:

• Environmental Engineering
• Waste Management
• Geotechnical Engineering

Background:

• Passive aeration is an efficient method for oxygen supply in landfills.
• Combining passive aeration with semi-aerobic landfilling offers cost-effective and energy-efficient solid waste (SW) treatment.
• Optimal strategies for passive aeration in semi-aerobic landfills require further investigation.

Purpose of the Study:

• To investigate passive aeration strategies in semi-aerobic landfills using numerical simulations.
• To identify key factors influencing the aerobic zone ratio (AZR) in landfills.
• To determine optimal design parameters for enhanced SW degradation.

Main Methods:

• Implementation of a coupled hydrodynamic and compartment model for SW degradation.
• Validation of the model using pilot-scale landfill data.
• Orthogonal experimental design to assess the impact of ventilation parameters (tube diameter, tube spacing, gas port diameter, landfill depth) on AZR.

Main Results:

• Passive aeration via funnel caps increased air input by 20% compared to natural convection.
• Landfill depth, tube diameter, and tube spacing significantly impact AZR; gas port diameter has minimal effect.
• Optimized parameters (D_T=0.3m, S_T=15.0m, D_GP=0.05m, LD=4.0m) enhance SW degradation by increasing AZR, particularly near ventilation tubes.

Conclusions:

• Passive aeration is a viable strategy to improve oxygen distribution and enhance SW degradation in semi-aerobic landfills.
• Optimized design parameters, especially larger tube diameters and spacing, are crucial for maximizing AZR.
• The findings support the development of more efficient and sustainable landfill management practices.