Performance assessment of landfill in-situ aeration - A case study

The assessment of landfill in-situ aeration eludes standardization as its application highly depends on varying local conditions. The prevailing work tries to assess the procedure performance by using typically available data. In the here presented case study the aeration pipes were applied horizontally. To evaluate the air-distribution and its effect on the landfill solid body, two monitoring fields with 10 × 10 m were created. From there in total 60 solid and 336 gaseous samples were taken over five years. As the material from the landfill was rather old and characterized by comparatively low reactivity, "new" material from a mechanical biological treatment (MBT) plant was introduced in the landfill. Additionally online gas data from eight technically separated landfill sections were analyzed during in-situ aeration. In total, about 46 Mm³ (0.27 m³/kg waste) air was introduced into the landfill body. The eight sections showed differences in reactivity (overall C-discharge was 8 g C kg^-1 dry weight, ranging from 4.5 to 11). With solid sampling we could not show a significant decrease in landfill TOC but for the introduced MBT-material. Ammonium in solid samples was significantly reduced (to 14.7% initial) and NO₃ significantly increased (2.1% initial). The reduction of the initial TOC (4.58%) was on average 11%. The application of horizontal landfill aeration led to a widespread air-distribution in a rather shallow landfill. Monitoring fields allowed for a screening of the impact of the measures on the solid body with reduced sampling costs.