Sweden – stabilisation of landfills with fly ash

In Sweden, large amounts of household waste have been land-filled and are now waiting for final covering. At the same time, more and more organic waste is incinerated, resulting in growing amounts of fly ash. International Wastenews, Waste Centre Denmark no. 1, 2005 reports that tests have been made with suspension of fly ash in water and in-jection in landfills with a view to stabilising the landfill body.



The hypothesis is that the CO2 generated in the decomposition of the landfilled waste reacts with the fly ash. This should result in a tempering process (carbonatisation) that should continuously sta-bilise the landfill. At the same time, the sulphate contents may also reduce methane generation. To test the hypothesis, pilot scale tests have been carried out in Södertälje, and laboratory scale tests have been carried out at the Technical University of Luleå.



The conclusion from the pilot test is that it is highly feasible to mix the ash with water to a pumpable suspension that can be injected without a risk of tempering in the pumps. More tests are planned with larger amounts of ash compared to this one in order to establish whether the stability is affected.



Source: RVF Utveckling 2004:16: "Injektering av flygaska i hushållsavfallde-poni" (Injection of fly ash in household waste landfills). The report, in Swedish, is available at Waste Centre Denmark

Check Also

Waste management poses challenges, but could unlock major environmental and economic gains

Every day, the city of Rio de Janeiro, one of the largest metropolises in the Southern Hemisphere, generates 17,000 tonnes of waste, ranging from large industrial debris to candy wrappers bought innocently at newspaper stands. While this waste presents a serious and urgent environmental challenge, it also fuels an increasingly significant portion of the economy, with benefits extending beyond financial gains. - When we look at developed European countries, many are already recycling between 40% and 50%, with some reaching 60%. From an economic standpoint, both recyclable materials and organic waste hold tremendous value - stated Adalberto Maluf, National Secretary for Environment and Environmental Quality at the Ministry of the Environment (MMA), during the Methane Forum: Climate Emergency Brake, at the Rio Nature and Climate Week. Citing a 2025 report, Maluf mentioned that Brazil literally throws away R$27 billion annually, while municipalities spend significantly more - R$45 billion - managing all this waste, often overlooking the environmental impact or economic potential buried in landfills and dumps. - We spend R$45 billion to collect and dispose of waste in landfills, yet we manage to recycle less than a third of the potential. I believe it will be necessary to review contracts, create performance-based remuneration mechanisms, and pay for both effectively sorted materials and those diverted from landfills - he added. According to the IBGE, 60.5% of Brazilian municipalities adopt some form of selective waste collection, and several initiatives serve as examples of how to manage city waste. In his panel presentation, Bernardo Ornelas, Project Coordinator at the Rio de Janeiro Municipal Urban Cleaning Company (Comlurb), highlighted Ecoparque do Caju, a national benchmark in waste management and recycling. There, received materials are sorted and can be used for biogas production, organic compounds for urban gardens, or human consumption, in the case of still...