Hydrogen sulphide adsorption on a waste material used in bioreactors

The biofilter packing, support or bed material, is considered to be the “heart” of the biofiltration system, especially when it also provides active biomass. Furthermore, when biodegradation performance is not effective, the ability of the packing material surface to retain or adsorb the contaminant is a desirable property. In this paper, a pelletized organic material has been researched in order to quantify and to model its adsorption capacity when used as bed material in biofilters. For comparison purposes, adsorption tests have been carried out using sterilized organic material and activated carbon. Adsorption equilibrium isotherms have been established for both materials in a H2S concentration range from 40 to 330 ppmv at room temperature. A type I adsorption isotherm for the activated carbon and type III for the organic material have been obtained. The experimental adsorption data for the activated carbon can equally be represented by both Langmuir and Freunlich models. However, only the Freundlich approach is adequate for the organic bed with KF = 9.61 mg1−n Ln g−1 of dry bed and n = 1.55. When the sterilized organic material is not dry, the contribution of absorption to the retention of the contaminant in the organic bed is negligible.