1 The Faculty of Engineering and Science, Aalborg University, VBN2 Section of Biology and Environmental Science, The Faculty of Engineering and Science, Aalborg University, VBN3 Department of Chemistry and Bioscience, The Faculty of Engineering and Science, Aalborg University, VBN4 Institut for Agroøkologi - Jordfysik og Hydropedologi
Water pressure drop as a function of velocity controls w 1 ater cleaning biofilter operation 2 cost. At present this relationship in biofilter materials must be determined experimentally as no 3 universal link between pressure drop, velocity and filter material properties have been established. 4 Pressure drop - velocity in porous media is much simpler and faster to measure for air than for water. 5 For soils and similar materials, observations show a strong connection between pressure drop – 6 velocity relations for air and water, indicating that water pressure drop – velocity may be estimated 7 from air flow data. The objective of this study was, therefore, to investigate if this approach is valid 8 also for coarse granular biofilter media which usually consists of much larger particles than soils. In 9 this paper the connection between the pressure drop – velocity relationships for air and water flow was 10 investigated using a common biofilter medium, Leca® consisting of rounded porous particles of 2 – 16 11 mm diameter. Pressure drop – velocity relations for water flow were measured for 14 different Leca ® 12 particle size fractions and compared to measurements of the pressure drop – velocity relations for air 13 flow in 36 different Leca® particle size fractions (including the 14 used for water flow). The 14 measurements showed that it is indeed possible to predict the pressure drop – velocity relationship for 15 water flow from the corresponding relationship for air flow not only for a given particle size fraction 16 but also across different particle size fractions.
Water, Air and Soil Pollution, 2013, Vol 224, Issue 4, p. 1-12