The Ministry of the Environment has contracted the Estonian Environmental Research Centre for a study with the aim to learn the composition of semi-coke and get a basis to decide whether it should be considered hazardous or non-hazardous waste. This information is important for the development of conditioning plans for semi-coke disposal sites. To date, semi-coke - being a waste resulting from oil shale pyrolysis - has been classified as hazardous waste in the Estonian Waste List. The study determined that only fresh semi-coke should be classified as hazardous waste while the older semi-coke (which has been stored for over 10 years) may be considered non-hazardous waste. According to Mr. Peeter Eek, Head of the Waste Department of the Ministry of the Environment, this implies that at the development of conditioning plans of the old semi-coke disposal sites the different age of different slopes should be taken into account. "According to the EU Landfills Directive, landfills are divided into three categories: those of hazardous, non-hazardous, and inert waste. Each category has got criteria for determination which waste may be deposited in those landfills. Therefore it is of importance to obtain an official and thorough overview of the composition of semi-coke, of its hazardous components, and of their change dynamics over time," said Mr. Eek. As a result of the study it was determined that the content of organic carbon /üldorgaanilise süsiniku/ in semi-coke is 12..14 mass per cent and the content of bitumoids 0.6..2.1 mass per cent. The measures pH of eluate of semi-coke obtained by laboratory leaching test was nearly 12 while the pH of semi-coke that had been stored for approximately ten years was 10 - this implies that semi-coke is a considerably alcaline substance. The content of oil wastes in semi-coke was measured to be 0.6..5 % . The investigation also indicated that in the long term salts - especially sulphides dissolving in water - may be discharged from the mineral part of semi-coke into the environment. The study also indicated that in the case of semi-coke no problems should be encountered concerning heavy metals or polycyclic aromatic hydrocarbons. The Waste List currently valid in Estonia (updated in 2002) is based on the EU Waste List. The latter does not include oil shale related waste, such waste have been added to the Estonian Waste List. According to the general logic of the EU Waste List, waste that have undergone the process of pyrolysis should be categorized as hazardous waste since they contain tarry and bitumenous substances. For additional information please contact: |
