Air biofiltering systems design and management for mitigation of olfactory impact from solid waste composting and preselection plants.

The present work compares the results of a few experimental surveys carried out in order to verify and optimize efficiency of classic air biofiltering systems applied to solid waste composting or preselection plants. A first comparison of project parameters is realized about data disposable from a few composting plants placed in Emilia Romagna and direct investigations are executed on the biofilter applied to the solid waste preliminary (preselection) plant of Piani di Tiedoli-Borgotaro (PR). Different conditions of management are tested in order to obtain increase in efficiency of odours removal. According with recent studies, smell measurement are compared with typical chemical odours indicators as metyl-mercaptan and dimetyl-sulphide with the aim to test, by modelling, empirical project criteria and to optimize regulation parameters in order to reduce odour emissions. All olfactory data, disposable since year 2006 to 2010, are furnished by Progress s.r.l company. Two olfactory monitoring campaigns have been expressly executed in different humidity conditions on the Piani di tiedoli Plant. Analysis are based on samples taken from final extraction pipe before biofilter intake ad from different points of out discharging surface of biofiltering bed. Functioning conditions of all biofilters have been simulated by numerical modelling based on attached biomass kinetics (Mancini et al. 2009) The obtained results reveal that modellization can be considered applicable such in classic composting plants, as to the waste collected in the Piani di Tiedoli preselection plant or to similar typology of commodity. Experimental results, interpreted by the model, permit to verify odour removal efficiency in function of design parameters as surface loadings, depth and diameter of biofiltering bed in different O.U. ranges for input concentrations.