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ŠTERBENK, E., PAVŠEK, Z., KOTNIK, K., DRUKS GAJŠEK, P.
EVALUATION OF PM10 CONCENTRATIONS IN AMBIENT AIR IN VELENJE AFTER THE FIRST YEAR OF MONITORING
KOMUNALNA ENERGETIKA / POWER ENGINERING, 12
Since autumn 2011 PM10 concentrations in ambient air are being monitored in Velenje within the Slovenian state network. Year-round data are available only for 2012; compared with data from other Slovenian towns Velenje is the least polluted among them. The annual average concentrations in Velenje are comparable with both stations in Ljubljana, as well as with stations in Koper, Nova Gorica and Hrastnik. In all these towns except Hrastnik, there are almost twice as many days on which the acceptable daily limits are exceeded than in Velenje. Lower values than in Velenje were recorded only at the control station in the Kočevsko area (Iskrba). PM10 concentrations were also measured within the Environmental Information System of the Šoštanj Thermal Power Plant (ŠTPP) in Šoštanj, Škale, Pesje and the mobile station at the Unit 6 site by the EIMV Company. Allowable concentrations were not exceeded in 2012 on any of these locations and the average annual values were similar to those in Velenje. This favourable situation mainly results from district heating of households in the valley. If homes and other buildings, which are district heated, were to be individually heated, total PM10 emissions into the temperature inversion layer would be higher than emissions from the ŠTPP. Around 200 tons of particulate matter is released into the atmosphere annually from the ŠTTP and about 80% of this mass represents PM10. A third of the Slovenian electricity and heat for heating buildings, as well as heat for industrial processes in the Šalek valley are produced by the ŠTTP at the same time.
ŠTERBENK, E., MAVEC, M., MLJAČ, L., DEBELJAK, B.
ENVIRONMENTAL IMPROVEMENT OF FLY ASH DEPOSITION IN THE ŠALEK VALLEY
KOMUNALNA ENERGETIKA / POWER ENGINERING, 17
The Šoštanj TPP (installed power of 809 MW) is the biggest thermal power plant in Slovenia. In the facility lignite coal from the Velenje Colliery is burned. Approximately 700 000 tonnes of fly ash results from electric power production every year. Fly ash is used for remediation of subsidence area damaged by coalmining. Fly ash was transported as slurry directly into the Lake Velenje up to 1982. After 1982 a dry landfill was constructed, while transport water still entered the lake. In 1994 the closed loop system for ash transport water was built and it has been operated since than. The previous high alkalinity of water from the Lake Velenje decreased in 3 years of operation of the closed loop system from pH over 12 to pH approximately 8. In 1995 the flue gas desulphurisation plants on unit 4 and in 2000 on the unit 5 were built. The product of desulphurisation is gypsum. Fly ash and gypsum have been mixed together as so-called stabilisat and transported to the subsidence area. The material is used for remediation of damaged area. Negative environmental impacts have been significantly reduced since the early nineties. The Šoštanj TPP management adopted an environmental improvement programme. The Velenje local community adopted a law, which required the Šoštanj TPP to reduce the degree of pollution from fly ash landfill. An ecological monitoring programme for solid waste disposal started in 1996 and has been performed on a regular yearly basis. It covers the most important pathways, so it comprises measurements of air, surface and underground water, water sediments, soil, and some vegetation. The results show very locally limited environmental impacts. The main impact has been observed in the surface water. In the early nineties of the 20th century the area used to be an ash dump. Over last two decades it has become a well-maintained site of remediation. The major part of site is grassed and partly used as a recreational area, although works are still in process.
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