Landfill simulator reactor experiments to investigate in-situ aeration for treating low-organic-content waste

Six landfill simulation reactors (LSRs) were set up to provide insights into the effect of aeration on the degradation of waste from a landfill with low organic content. The waste comprised industrial, combustible and construction waste, among others. One LSR was used as a control (LSR C) under anaerobic conditions, whereas the other five (LSR 1 - LSR 5) were assigned different aeration flow rates (7.1 - 40.8 mL/min), representing diverse aeration periods for the field experiment, and assuming oxygen (O₂) as the limiting factor. Carbon emissions in the gas and liquid phases were monitored, as well as nitrogen content in the resulting leachates. Accumulated carbon emissions in the gas phase for the aerated LSRs were not significantly different between treatments, with an average removal of 113 g of carbon over the 351 days of the experiment (7.6 g C/kg DM). This was equivalent to ∼12 % of the original total organic carbon (TOC) in the waste, proving that aeration can accelerate waste degradation. In comparison, emissions from the anaerobic LSR C only reached 2.5 % of the original TOC, with C emissions of 23.5 g (1.6 g C/kg DM). Aeration reduced ammonium leaching and resulted in a temporary increase in nitrate. A subsequent experiment to study the O₂ consumption rate showed that the aerated waste had low consumption at 20 °C but still a significant one at temperatures of 50 and 70 °C (by factors of 2.5 and 2.6), suggesting that organic matter was still available for degradation.