42 003    In the Flemish legislation, no odour assessment framework is implemented, despite that odour-related permit applications require the inclusion of an odour impact study. For livestock farming, odour emission factors, derived from olfactometric measurements (ouE), are widely used. Contrastingly, the available assessment tools, based on earlier odour impact research, utilize sniffing measurements (se).

   To allow comparison between the two units of odour, it is assumed that 1 ouE equals 1 se. For most groups of livestock animals with a rather constant growth cycle (e.g. pigs), this comparison is deemed valid and suitable for evaluating the odour impact. However, the theoretical assessment of broiler chicken emissions can be questioned, as the olfactometric emission factor of 0.33 ouE/s.animal results in almost no odour impact.


  Fig. 1.: Chromatogram comparing sampling method. Black: tube spiked with siloxanes and toluene; pink: gaseous sample in sampling bag of siloxanes and toluene loaded onto tube; blue: gaseous sample in canister loaded onto tube There is increasing interest in the usage of biogas produced from wastewaters, anaerobic digesters and landfill sites as a source of green energy. Biogas generated from these types of sites require process monitoring due to contamination with siloxanes derived from hygiene products, detergent, antifoams, etc. Siloxanes are troublesome impurities in biogases in engine sources.

   The combustion of biogas can lead to deposits of silicon dioxide particles which can cause problems and damage different kind of gas engines or turbines through their build up and via corrosion.The objective of this study was to develop a method on a thermal desorption unit coupled to a gas chromatography and mass spectrometer (TD-GC-MS) to identify and quantify siloxanes present in a representative biogas sample with a low detection limit (µg/m3). Enabling the occurrence of siloxanes in a biogas matrix and efficiency of the removal processes present in the industry to be monitored.

Mesones  The proposed Advanced Biofiltration (mixed organic/inorganic) can be considered the Best Available Technology (BAT) to treat odorous emissions from MSW treatment plants, composting and WWTP plants among others, typically achieving final odour concentrations below 1000 uoE/m3 or 95% efficiency.

   The applied sensorics includes the most relevant parameters (COVs, H2S, NH3). The integration of these parameters in the Airadvanced™ platform allows real-time monitoring of the correct functioning of the biofilter and thanks to the meteorological (WRF) and dispersion (CALPUFF) models allows the client to visualize the impact in real time and the prediction of impacts up to 72 hours.

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