1. Institute of Environmental Engineering, Wrocław University of Environmental and Life Sciences, 24 Grunwaldzki Square, 50-363 Wrocław, Poland, Telephone: +48 713205549; Telefax: +48 713205579;(corresponding author)
2. Institute of Environmental Engineering, Wrocław University of Environmental and Life Sciences, 24 Grunwaldzki Square, 50-363 Wrocław, Poland, Telephone: +48 713205549; Telefax: +48 713205579;