Evaluation of aeration for stabilising a landfill with low-organic waste

The applicability of landfill aeration for stabilising old and low-organic waste was tested at the AV Miljø landfill, Denmark. Preliminary air injection tests achieved higher aeration flow rates in the southwest area (250-370 m³ h^-1) compared to the northeast (150-200 m³ h^-1) of the waste cell, with visible response pressure up to ∼ 40 m away from the injection point. A five-week aeration test with an air injection flow of 200 m³ h^-1 injected at 5-6.5 m depth resulted in a temperature increase of ∼ 10 °C in the waste body, indicating increased aerobic biological activity, especially after aeration stopped and the winter air did not cool down the waste. Aeration effectively transformed anaerobic conditions into aerobic, thereby accelerating organic waste degradation and significantly reducing CH₄ concentrations from 53.4- 67.7 to 0.2 - 15.3 %vol. Air distribution during aeration was predominantly horizontal, with nitrogen found at an influence radius of over 80 m and oxygen depletion within 50 m. The estimated oxygen consumption rate was low, at ∼ 0.002 mg O₂ g DW^-1 h^-1, as expected for waste with low organic content. Based on the aeration radius of influence, the facilities for full-scale aeration experiment were redesigned, reducing from 60 projected wells to only 15 wells, reducing costs. A full-scale aeration system is planned to further investigate the benefits of aeration for landfills with low organic content.