Pressure loss (ΔP) is a key parameter for estimating biofilter energy consumption. Accurate predictions of ΔP as a function of air velocity (V) are therefore essential, to assess energy consumption and minimize operation costs. This paper investigates the combined impact of medium particle size and shape on the V - ΔP relationship. V - ΔP measurements were performed using three commercially available materials with different particle shapes: crushed granite (very angular particles), gravel (particles of intermediate roundness) and Leca® (almost spherical particles). A total of 21 different particle size fractions, with particle sizes ranging from 2 to 14 mm, were considered for each material. As expected, ΔP decreased with increasing particle size in agreement with earlier findings. ΔP, however, also showed a tendency to decrease with increasing particle roundness especially for fractions containing smaller particles. A new model concept for estimating V - ΔP across different particle size fractions and shapes was proposed. This model yielded improved prediction accuracy in comparison with existing prediction approaches.
Journal of Environmental Engineering, 2013, Vol 139, Issue 12, p. 1424-1431