H2S biofiltration using expanded schist as packing material: performance evaluation and packed-bed tortuosity assessment

BACKGROUND: The aim of this work was to test an innovative packing material (expanded schist) for H2S biofiltration in order to determine the packing material performance in terms of elimination capacity, removal efficiency and pressure drop changes. Additionally, the changes over time of bed characteristics, especially tortuosity, were evaluated according to porosity measurements. RESULTS: Schist material can treat large loading rates (up to 30 g.m-3.h-1) with 100% efficiency at an empty bed residence time (EBRT) of 16 s, which is much better than most results reported in the literature. The porosity of the packed bed is around 40% (tortuosity estimated to range from 1.5 to 2.0) which leads to pressure drop measurements in the range of 1080 Pa m-1. CONCLUSION: Schist is a good material for H2S biofiltration in terms of mechanical stability, removal efficiency and effective treatment of high H2S loading rates. Schist is a material that provides the appropriate environment for micro-organisms by itself. This trend should be confirmed over a long period. Copyright (c) 2012 Society of Chemical Industry