| Summary: | In 2000 Telge Återvinning - a waste management recycling company - started investigating ashes from incineration of industrial and biowaste waste. The company was given a permit from the Swedish Environmental Court to cover four hectares of the house hold waste landfill area. In 2006 the company received an unlimited permit to cover the remaining part of the landfill when the works end some thirty years later.Ashes were used the first time in 1966 for testing. Literature studies indicated the ashes can have a low hydraulic conductivity under certain conditions. In 1999 collaboration started with the Division of Waste Science and Technology at Luleå University of Technology.Residuals from household and industrial waste were subject to investigation. Initially, biowaste incineration products were subject to testing and were later extended to other waste products, e.g. sludge, contaminated soils, foundry, and compost material. Several different sub-fractions of ashes were included in the investigation e.g. bottom and fly ash, various slag products after up-grading including dewatering, separation and sifting. Subsequently, a complete covering system of a landfill consists of residuals.Six test areas were outlined in order to give a good representation for cover construction in flat and steep areas with different compositions of liner material.The results show that in all areas the hydraulic conductivity construction yields less then 50 liters per square meters and years and can be less the than 5 liters in a repository for hazardous waste if required. In accordance with literature data the field observations show the liner material constructed only by ash material under certain conditions can form a monolithic structure due to very slow processes thus indicating small pore volumes that unable water - air to interact with other media.The concept of using ash can be related to natural analogues of volcanic ashes and has been used in old defence walls and other buildings thousand years back. The last part of the ...
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