Tedlar bags, which are widely used to collect air samples, especially VOCs and odorous atmospheres, can allow humidity to diffuse when relative humidity levels differ between the inside and outside. Starting with dry air inside the bag and humid air outside, we monitored equilibrium times under several conditions showing the evolution and influence of collected volumes and exposed surfaces. A double-film Tedlar bag was made, to limit the impact of external humidity on a sample at low humidity level. With the addition of a drying agent between both films, the evolution of humidity of a sample can be stopped for several hours. When a VOC mixture was monitored in a humid atmosphere, humidity was decreased but no significant evolution of VOC concentrations was observed.

Main conclusion New non-destructive approach to evaluate the retting process was investigated. Increase of retting duration led to a decrease of VOCs emitted by plants and change of color and plant odor. The variation of VOCs and odor could be used as indicators for the degree of retting.

BACKGROUND To improve process design, and scale‐up of gas biofilters, a thorough understanding of compounds degradation mechanisms within model engineering biofilters is needed. The aim of this study is then to investigate the spatial distribution of pollutants removal within an experimental semi‐industrial biofilter fed with industrial emissions from a rendering plant. RESULTS A stratification pattern of pollutants removal has been highlighted: nitrogenous compounds, esters, volatile fatty acids (VFA), alcohols, ketones and aldehydes are completely or mostly removed especially in the biofilter layers near the gas inlet. In return, the removal of sulphur compounds seems to begin when nitrogenous and oxygenated compounds are almost fully degraded. A sequential degradation of sulphur compounds is also observed: hydrogen sulphide is eliminated in the biofilter section near the gas inlet while methylmercaptan (removal efficiency 87%) and dimethyl disulphide (DMDS) (removal efficiency 73%) are mainly eliminated in the second half of the column. CONCLUSION An on‐site semi‐industrial biofilter used for waste gas abatement in an animal‐rendering plant exhibited spatial distribution of the compounds removal efficiency. The removal of organic sulphur compounds is not complete. Hence, this work emphasizes the importance of improving gas biofilters to achieve complete elimination of pollutants causing unpleasant odours. © 2014 Society of Chemical Industry

En informatiqueÉcole doctorale I2S Unité de recherche LGI2P et LGEI Vers une approche non-orientée pour l'évaluation de la qualité des odeursPrésentée par Massissilia MEDJKOUNE Le 30 mars 2018 Sous la direction de Jacky MONTMAIN et Jean-Louis FANLO Devant le jury composé de M. Eric Gaussier, Professeur, Université Grenoble Alpes M. Patrice Bellot, Professeur, Université Aix-Marseille M. Serge Garlatti, Professeur, IMT Atlantique M. Michel Beigbeder, Maître-Assistant, Mines Saint-Etienne M. Jacky Montmain, Professeur au LGI2P, IMT Mines Alès M. Jean-Louis Fanlo, Professeur au LGEI, IMT Mines Alès M. Sébastien Harispe, Maître-assistant, IMT Mines Alès M. Stéphane Cariou, Maître-assistant, IMT Mines Alès Mme Cécile Coulon-Leroy, Enseignant-chercheur, ESA

The impact of pollutants on production quality in nanotechnology necessitates reduction of contaminant levels in cleanrooms. So, devising a global airborne-pollutant indicator (GAPI) for rapid determination of the level of pollution and its danger to the process is justified. This tool used relative impact weights of the different molecules to quantify the pollution. A calculation of impact weight is proposed in this paper. Impact weights could take into account several characteristics of the molecules (molecular volume, sticking coefficient, ...). They could also be combined to be as close as possible to reality. An example of calculations of the impact of molecular volumes on air quality is given.