Durability assessment of landfill cover based on organic matter and fly ash

摘要

Closures of waste landfills face similar problems as tailing covers. Geotechnical, biological andweathering processes and how these control the capping constructions life span are of interest.The aim in both cases is to reduce leaching and corresponding negative effects on theenvironment. Laboratory studies Sundberg et al. 2003, Wikman et al. 2005 and Macsik et al.2006 indicated that sewage sludge stabilized with fly ash, resulting in a product called FSS, has agood potential to be used as landfill liner. Design and construction of a final closure cap, withspecial focus on the landfill liner, was carried out in order to reduce the amount of waterpercolating through the landfill and to minimize the effect on the surrounding environment for along time span. In this project FSS was used as liner and investigated during a three year periodon two landfills, one outside Eskilstuna and one in Alvkarleby, Sweden. The results showed that the manufactured FSS can be used as landfill liner on a large scale. Thehomogeneous quality, strength and low permeability of FSS was even better than the set criteria.Though, the quality of fly ash and sewage sludge has to fulfill certain quality requirements, e.g.regarding water and dry solid contents. Laboratory and field tests indicate that the liner is durableas degradation rate is low. FSS is olso a possible cover solution on tailing covers.