Redevelopment of contaminated sites Ritzer landfill, Küttigen

The Ritzer in Küttigen near Aarau was initially a quarry for a cement manufacturer, then from the 1960s onwards a landfill site for rubbish from the town of Aarau and the municipalities of Küttigen and Roth. A sports centre was built on the former landfill site. Contaminated site investigations showed that relevant quantities of landfill gas were leaking from the ground surface, which meant that the landfill site had to be remediated.

We carried out the detailed investigation and developed the remediation concept in an interdisciplinary team of internal and external experts. The remediation aims to accelerate the natural decomposition process in the landfill body by dewatering and degassing the landfill body. A 20 metre deep vertical shaft enables horizontal wells to be drilled as a basic drainage system. The landfill leachate is pumped onto the site and pre-treated. Vertical wells and a superficial gas drainage layer are constructed to collect the landfill gas. The gases will be extracted and disposed of. The construction work, which will take around four years, will include a one-year rest period to allow the landfill contents to settle. New grass pitches will be laid after the redevelopment. However, the project of the century is not yet complete for the municipality. It is expected to last over 50 years, including aftercare.