1. Institute for Sanitary Engineering and Water Pollution Control, University of Natural Resources and Applied Life Sciences, Vienna, Muthgasse 18, A-1190 Vienna, Austria (E-mail: guenter.langergraber@boku.ac.at)
2. s::can Messtechnik GmbH, Herminengasse 10, A-1020 Vienna, Austria (E-mail: office@s-can.at)
3. hydrophil, Lerchenfeldergürtel 43, Top 6/3, A-1160 Vienna, Austria (E-mail: niki.fleischmann@hydrophil.at)