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Low-calorific lignite from Kolubara open-pit mines is mainly used for heat and power generation in PE 'Thermal Power Plants Nikola Tesla'. The IPCC methodology suggests that CO2 emissions by fossil fuel combustion shall be calculated as product of fuel mass and standardized (country or even region related) values of lower heating value, carbon emission factor and factor of oxidation of combusted fuel. This approach doesn't take into account the influences of unit thermal efficiency as well as fundamental characteristics of combustion process, the most important influencing factors on overall CO2 emission. This paper presents the results of calculation of specific CO2 emissions by three different approaches: (a) using the observed linear correlation for calculation of carbon emission factor of the raw lignite, (b) based on the level of CO2 in the flue gas measured at 6 different power plant thermal units 'Nikola Tesla' A and B, (c) based on the mass balance of carbon in the coal, flying ash and bot tom ash. Comparing all the results, we conclude that the best solution is obtained by using the observed linear correlation for calculation of the carbon emission factor of the raw lignite. The calculation of specific CO2 emissions based on the measured flow rate and the share of CO2 in the flue gas gives higher, while calculation based on the carbon mass balance gives less values for the specific CO2 emissions. Higher values for specific CO2 emissions and some dissipation of these results is obtained for units A1 and A2 at output power of about 200 MW, than in the case of units whose output power during the test was over 300 MW - units A4 and A6, or over 600 MW - units B1 and B2.

In this paper a comparative risk assessment of the exploitation of old and new ash disposal sites in Kostolac is given. Risk assessment is carried out according to the FMEA (Failure Modes and Effects Analysis) method in combination with a risk matrix, which includes a detailed elaboration of potential accident scenario at disposal sites and analysis of consequences that accident can cause. As a potential accident scenario only hydrological scenario is taken into consideration, which is based on the influx of large amounts of precipitation, the cause of the largest number of accidents at industrial disposal sites. Analyses of environmental consequences, potential human losses and economic consequences are given. According to the risk matrix it is found that both of disposal sites are in the 'blue' zone of risk, which is interpreted as a tolerable level of risk, although the new disposal site is still in a better position than the old one because the expected level of risk is lower by one degree.

U termoelektranama (TE) Javnog preduzeća „Elektroprivreda Srbije“ (JP EPS) koje u kotlovima sagorevaju lignit, kao nus produkat nastaje godišnje oko 6 miliona tona letećeg pepela. Potencijalno tržište za upotrebu letećeg pepela postoji, ali ga za sada koriste isključivo cementare. Radioaktivnost letećeg pepela može da predstavlja jedan od važnih razloga protiv njegove šire upotrebe u građevinskoj industriji Srbije. Merenje radioaktivnosti u termoelektranama redovno se sprovodi od 1990. godine. U radu su prikazani rezultati dvadesetogodišnjih merenja radioaktivnosti letećeg pepela u termoelektrani Nikola Tesla B (TENT B) u Obrenovcu. Uporedno su prikazani podaci o sadržaju prirodnih radionuklida u uglju koji se sagoreva u kotlovima TENT B poreklom iz kolubarskog basena i pepelu koji nastaje prilikom sagorevanja uglja. Na osnovu dobijenih rezultata o sadržaju prirodnih radionuklida zaključuje se da se pepeo iz termoelektrane Nikola Tesla B može odlagati uživotnu sredinu. Pepeo se može koristiti i u građevinarstvu, u niskogradnji. Kod primene u visokoj gradnji udeo pepela kao dodataka drugim građevinskim materijalima zavisi kako od njegovih fizičkih i hemijskih karakteristika, tako i od specifične aktivnosti 226Ra, 232Th i 40K. Serbian thermal power plants (TPPs) produce Siliceous fly ash from lignite in the quantity of approximately 6 million tons per year. The Potential. Market for the use of fly ash is operational, but for the time being, only Used by cement producers. Fly ash radioactivity could be one of the major points of concern When larger use of fly ash is planned, particularly in the Serbian construction industry. Radioactivity measurements have been conducted regularly from 1980. This paper presents the results of a ten-year fly ash radioactivity measurements at the Nikola Tesla B TPP located in Obrenovac. In addition, the paper compares the natural radionuclides coal content data combusted by the Nikola Tesla B TPP boilers coming from the Kolubara Basin and ash created during coal combustion. Fly ash created in the Nikola Tesla TPPs boilers is characterised by the increased concentration of the natural radionuclides content compared to coal. This is the so-called technologically enhanced natural radioactivity (Technologically Enhanced Occurring Radioactive Material - TENORM) of industrial waste, whereas the average specific activities: Th-232 in coal amount to 25.2 Bq/kg, and in fly ash and coal 84.2 Bq/kg and U-238 38.3 Bq/kg, respectively. Following the obtained natural radionuclides content results it may be concluded that the Nikola Tesla B TPP ash may be disposed into the environment. Ash may be used also in the construction industry (civil engineering). In building construction applications, ash share as the additive to other building materials depends from its physical and chemical characteristics, as well as from the radionuclides activity: Ra-226, Th-232 and K-40. Unlike the thermal power plants regularly (once a year) testing the specific natural radionuclides activity in the combusted coal and boiler fly ash, the Electric Power Industry of Serbia has not performed large-scale investigations of the natural radionuclides content in coal within the Kolubara Mining Basin. Natural radionuclides content in fly ash is compared to the combusted coal some 3-4 times higher and may present a limitation for applying ash in the construction industry. In view of the above, and considering the construction industry interests in using the Nikola Tesla B TPP ash, regular investigations of the natural radionuclides content in ash created in the thermal power plants should be carried out, together with the Kolubara Mining Basin coal combusted by the Nikola Tesla B TPP and other PE EPS thermal power plants. The current Kolubara Mining Basin coal characteristics investigation programme should be supplemented by the natural radionuclides content of the uranium (U-238 and Ra-226) and thorium series (Th-232) and potassium 40(K-40).

The aim of this study was to investigate the possibilities and efficiency of heterogeneous Fenton process with the use of fly ash from thermal power plants Kolubara, Serbia, as the catalyst in the degradation of industrial azo dye Zetanyl Rosso B-NG. The effects of various experimental parameters such as pH, temperature, concentration of fly ash, the initial concentration of H2O2 and initial concentration of dye on the kinetics and efficiency of decolorization were investigated. Simultaneous leaching of iron from fly ash was monitored. The optimum conditions had been determined, and it was found that decolorization efficiency obtained after 150 min of reaction, was about 98.9%. The optimal parameters were: initial pH = 3; [H2O2]0 = 6 mM; dosage of fly ash = 0.1g/l (for dye concentration of 100 mg/l); temperature = 22 °C. The effectiveness of the applied treatment for mineralization of dye solution was investigated, under optimal conditions determined by the examination of various factors influencing the decolorization process at the specified contact time. The maximum achieved reduction of total organic carbon content was 96.5%. The results indicate that the reuse of fly ash as the catalyst support in •OH production in this process achieves significant efficiency in terms of decolorization, 94.4% and mineralization, 89.6%. Futhermore, fly ash showed adequate stability during the reaction (low iron leaching, concentrations under optimal reaction condition were about 2 mg/l).