1. Department of Hydraulics, Soil Science and Agricultural Engineering, School of Agriculture, Aristotle University of Thessaloniki, GR 54124 Thessaloniki, Greece
2. Biogas Lagada S.A., Biogas Plant, Organic Waste Treatment & Electricity Generation, Plot 677 Kolchikou, GR 57200 Kolchiko Lagada, Greece
3. Burmeister & Wain Scandinavian Contractor, Gydevang 35, DK 3450 Allerød, Denmark
4. Department of Chemical and Biochemical Engineering, Technical University of Denmark, DK 2800 Kgs Lyngby, Denmark