Oxygen intrusion into waste in old landfills of low organic content

Oxygen invasion into old landfills was studied by assuming the installation of gas venting pipes to promote stabilization of waste. In an experiment using a column pack with old incombustible waste, oxygen intrusion was observed and the oxygen consumption rate was estimated. Oxygen diffused into the waste layer very quickly in the initial stage of the experiment, but oxygen concentration increased only gradually due to reduced gradient and decreasing oxygen consumption. The maximum oxygen consumption rate in packed waste was one-third of that in loosely deposited waste in a beaker measured in a respiration test. A mathematical model was created which fitted the experimental data well and a three-dimensional simulation of a full-scale landfill and a sensitivity analysis were performed.