Oil Shale Waste: One of the Biggest Challenges for Estonia

The Estonian Environmental Review 2013 is providing latest information about the state of the environment of Estonia. The chapter “waste“ presents a comprehensive overview on that issue and especially on Estonian difficulties with the handling of oil shale waste.

In Estonia, significant progress has been made in recent years in the field of waste management. The number of landfill sites is decreasing. However, despite the increased recovery of materials waste generation continues to be a serious problem. Huge quantities of waste (including hazardous waste) are especially generated in Estonia by the oil shale industry. The industry is seeking ways to recover and reduce waste. Reducing the amount of oil shale waste is one of the biggest challenges for Estonia.

In 2007 to 2011, over 85 per cent of all waste was generated by the industrial sector, with 79 per cent of total waste comprising waste generated by the oil shale industry and energy sector. Hazardous waste generated by the oil shale industry still constitutes nearly 95 per cent of the total amount of hazardous waste. This determines the share of hazardous waste in total waste generation, which has been between 40 per cent and 47 per cent in recent years and depends mainly on the intensity of the production of oil shale energy and shale oil. The wood and cement industries also generate large volumes of waste but most of this waste is recovered.

A change in 2011

A surge occurred in 2011 when waste recovery increased to 55 per cent. The main reason was the increased recovery of oil shale mining waste, caused by a concurrence of different circumstances: The semi-coke landfills in Kohtla-Järve were closed and pitch lakes containing the waste from oil production were filled with mine waste; also, several large-scale road construction projects were launched (Aruvalla-Kose, Haljala junction, Luige junction, etc.) in which mine waste is used as a trackbed filling material, and the construction of a recreational centre began in Mäetaguse rural municipality.

The pollution charge for depositing oil shale mining waste and tailings is on the increase. Increased pollution charges for depositing waste mainly affect the AS Eesti Energia Kaevandused company whose pollution charges depend on how much mine waste they manage to recover. Therefore, for the past five years, the company’s priority has been to increase the share of recovered waste. The company has constructed several powerful crushed stone production plants. About 70 per cent of the mine waste generated by the company was recovered in 2010 and 2011, as compared to 20 per cent in previous years. However, such growth is not sustainable.

Recovery of oil shale ash increasing

The recovery of oil shale ash from power generation, which accounts for about 33 per cent of total waste, is also increasing. Oil shale ash is used in the production of building materials as well as in various mixes and large-scale mass stabilization processes. In agriculture it is to reduce the acidity of the soil and in the production of mineral fertilizers. AS Eesti Energia is seeking in cooperation with technology researchers new and more efficient methods for oil shale ash recovery. In 2007 to 2011, about three per cent of the total volume of oil shale ash was recovered.

Unfortunately, energy production from oil shale inevitably generates huge quantities of waste due to the high mineral content (more than 50 per cent) of oil shale. Improved technology and more efficient use of resources, however, present opportunities for reducing waste generated per production unit. In the field of oil shale energy this is achieved by replacing old boilers with new ones that are based on fluidized bed combustion technology, which has clearly reduced the amount of oil shale ash per production unit.

Predominant method: landfilling

The main method of disposal has been the deposition of waste in landfills and this will continue to be the predominant method in the future – as long as oil shale continues to be mined and used for energy and shale oil production. Wastes from oil shale mining and the energy sector accounted for 95 per cent of total waste deposited in landfills in the last decade. In 2011, 43 per cent of waste was deposited in landfills; however, when broken down by types of waste, it appears that the decrease in the volume of waste deposited in landfills mainly occurred on account of wastes from mineral non-metalliferous excavation, i.e. mine waste. While an average of four million tonnes of mine waste was disposed of in the decade preceding 2011, in that year the amount was only as much as 826,624 tonnes.

New recovery technologies

The oil shale mines in Ida-Viru County have developed an original way of recovering mine waste: The enormous heaps of mine waste are redeveloped into recreational facilities. New ways have been sought for increasing the use of recovered oil shale ash in road construction, cement production, for the neutralization of acid agricultural soil and potentially also for filling underground mines. This should considerably decrease the amount of landfilled waste.
The most voluminous and also the most dangerous waste from oil production are waste pitch or fusses. By implementing a new filtering technology, AS VKG Oil has significantly reduced the generation of that type of waste.

Other types of hazardous waste: stable amount

The generation of other types of hazardous waste than oil shale waste has been more or less stable over the years. The amount of other types of hazardous waste generated in Estonia in 2010 was 162 kilogramme per inhabitant. By comparison, the EU27 average in the same year was 188 kilogramme. Other types of hazardous waste generated in large volumes are:

  • cement clinker dust trapped by electric filters at cement production plants (55,000 tonnes in 2011);
  • waste consisting of various oil products, including tank bottom sludge, bilge water and waste oils (over 100,000 tonnes in total);
  • soil polluted with hazardous substances removed from objects that have been cleaned (31,400 tonnes);
  • wood polluted with hazardous substances (7,400 tonnes);
  • end-of-life vehicles (11,400 tonnes);
  • construction materials con­­taining asbestos, including fibre-cement boards (eternit) (3,900 tonnes);
  • lead batteries (2,800 tonnes), etc.

8,166,000 tonnes landfilled

The bulk of hazardous waste generated in Estonia was deposited in landfills (a total of 8,166,000 tonnes in 2011) because recovering such huge quantities of waste, in particular the waste generated by the oil shale industry, is difficult. However, 1,139,000 tonnes of hazardous waste was recovered in 2011, mainly phenol-containing water that was used to produce fine chemicals (443,000 tonnes); semi-coke used in closing the landfills in Kohtla-Järve and Kiviõli (280,000 tonnes); cement clinker dust used as lime fertiliser (30,400 tonnes), etc.

A total of 21,200 tonnes of hazardous waste were used to produce energy, including 12,900 tonnes of oil containing waste that was used as an alternative fuel to operate the rotary kilns of AS Kunda Nordic Tsement.

The full chapter of the Estonian Environmental Review 2013 on waste can be downloaded from www.keskkonnainfo.ee/failid/ky_2013_eng_4.pdf


Photo: Mark A. Wilson (Department of Geology, The College of Wooster)