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International audienceBACKGROUND: 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 Industr

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a b s t r a c tMembrane bioreactors (MBR) technology for wastewater offers many advantages over conventional technologies such as high effluent quality, less footprint and others. The main disadvantage of membrane bioreactors (MBR) is related to membrane fouling, which is mainly caused by extracellular polymeric substance (EPS) and soluble microbial products (SMP). This research studied EPS and SMP dynamics at different heights of a submerged anaerobic membrane bioreactor (SAMBR). The SAMBR was operated under two organic loading rates (OLR) (0.79 and 1.56 kg/m 3 d) and was fed with synthetic wastewater with glucose as the carbon source. The results showed percentages of chemical oxygen demand (COD) removal above 95% and the highest COD removal rates were observed at the bottom of the reactor (>83%) for both OLR. The EPS showed a stratification with highest quantities in the supernatant. For the SMP the highest concentration was in the bottom of SAMBR where utilization predominated associated products whereas in the SAMBR supernatant predominated biomass associated products. The OLR change led to a significant increase in SMP accumulation but not in EPS. These facts showed that EPS and SMP dynamic in the SAMBR seemed to be mainly influenced by biological activity, total suspended solids concentration and substrate composition.