conferencePaper 5th Conference on Sewer Processes and Networks Delft, The Netherlands International Water Organisation (IWA) Zgheib S. Gromaire M.C. Lorgeoux C. Saad M. Chebbo G. Van de Meulen M. Ten Veldhuis J.A.E. Schilperoort R.P.S. Sterols: a tracer of organic matter in combined sewers 2007 275–286