Preconcentration, thermal desorption & analysis of volatile organic compounds

International audienceVolatile organic compounds ("VOC") cover a large number of compounds, of which some are toxic (benzène, 1,3-butadiene...) and others are involved in atmospheric chemistry, such as the so-called "ozone precursors". Both benzène and ozone precursors are now covered by European daughter directives. VOC represent a complex mixture and are present in ambient air at low concentrations: from tens of ppbv to sub-ppbv concentration levels. Therefore, their measurement requires preconcentration and high resolution separation. The precise sampling and measurement technique depends on the kind of compounds to be measured. However thé principle of the measurement remains the same and can be presented as in Figure 1. Solvent extraction of samples taken on activated carbon will not be covered by this paper, as this procedure is less sensitive and the solvents used are harmful to the environment

Paramètres de détermination de la stabilité des déchets. Comparaison de différents modes de gestion des déchets non dangereux

National audienceLes déchets non dangereux, déchets ménagers et déchets industriels banals, sont généralement incinérés ou enfouis en centres de stockage anciennement dits de " classe II ". La gestion de ces centres de stockage répond à des critères très précis, tant au cours de l'exploitation qu'après l'arrêt de celle-ci. En particulier, un suivi des sites fermés est imposé pendant 30 ans, période pendant laquelle la matière organique, contenue dans les déchets, produit par dégradation biologique d'importantes quantités de biogaz et des lixiviats chargés. A côté de ce mode de stockage " classique ", il est apparu depuis quelques années des modes de gestion différents, qui visent à limiter les émissions gazeuses et liquides des déchets enfouis. Il s'agit d'une part, du fonctionnement de CSD en casiers de type bioréacteur, et d'autre part de l'enfouissement de déchets pré-traités biologiquement. A ces nouveaux modes de gestion s'ajoutent le tri en amont avec les collectes sélectives, et un traitement mécanique plus ou moins poussé avant le traitement biologique, permettant de diminuer la part de produits recyclables ou inertes, de rendre plus accessible la matière organique contenue dans les déchets, et d'homogénéiser la matrice

Quality of composts from municipal biodegradable waste of different origins

International audienceMechanical biological treatment of municipal solid waste is increasing rapidly inaFrance as well as in other European countries. One of the outputs of this treatment is a compost prepared from the organic matter of the waste. This organic matter can be either collected selectively from the customers as biowaste, or separated from the total MSW in the plant. Unlike in Germany or Austria, where only the compost from selective collection of biowaste is allowed to serve as an amendment, in France the use of the compost is based on its compliance to a quality Standard. We present here the first results on an enquiry concerning the quality of composts from the two processes, determined on 5 French plants, between 2008 and now. All the composts fulfill to the prescriptions of the Standard and can be used as soil amendments

L'oxydation du biogaz : un moyen de réduire les émissions résiduelles

National audienceDepuis le début des années 2000, plusieurs facteurs concourent au besoin de développement de nouveaux modes de gestion des déchets municipaux. Parmi ces nouveaux modes de gestion, la filière de traitement mécanobiologique (TMB) permet de réduire très significativement les émissions résiduelles de biogaz. Les émissions de carbone sous forme de biogaz constituent en effet la très grande majorité des émissions de carbone des déchets enfouis, quelque soit la filière retenue (filière conventionnelle, bioréacteur, TMB)

Risk assessment and comparison of short-term and long-term emissions for different treatment and disposal phases of MSW

International audienceA research program including a comparison between short term and long term emissions of MSW landfill started in 2006. The goal of that program was to access the human health chronic risk of three different waste disposal processes (anaerobic with/without leachate recirculation, with/without aerobic pretreatment) and to provide new criteria for the disposal site. A methodological approach using both calibration of the short term fluxes by in situ measurements and the prediction of long term fluxes by the use of exponential decreasing functions was explored. The identification of contaminant species was made by qualitative and quantitative concentration measurements done in a first stage on the landfill gas, and the collection of chemical leachate load measurements. At this stage of the study, the work did not show specific chemical contaminant species for the different waste disposal

On-site assessment of methods to measure gaseous emissions from biological treatment of waste

International audienceLandfilling of biodegradable waste must decrease to fulfil the Council Directive 99/31/EC on landfills, in order to reduce the emission of gaseous and liquid pollutants during the landfill lifetime. Therefore, pre-treatment of the organic fraction of municipal waste prior to landfilling is being developed in several countries. In France, the organic fraction is either separated and treated through selective collection of biowaste, or through mechanical sorting in the plant followed by biological treatments (anaerobic or aerobic), the refuses only being landfilled. Or the mixed waste is stabilized by an aerobic process before landfilling. These different processes emit gases which may be harmful for health or the environment (toxic, explosive, odorants, greenhouse gases...). Some of the emissions can be collected and treated through biofilters, while other gases are emitted by surfaces (typically, compost windrows) and cannot be collected unless they are enclosed. Also, the efficiency of the biofilters must be assessed. IRSTEA and INERIS have been working together for several years on the use, comparison and improvement of surface emission measurement methods, applied to biological treatment plants of solid waste. Gaseous emissions were studied on: composting process of pre-sorted organic matter from mixed waste, with a small or larger mesh and porosity, in either turned or aerated windrows, on biofilters, and on landfills which are located beside the composting plants. Depending on the ventilation air flux, different measurement methods were used: static (accumulation), dynamic or chimney type chambers, and a total cover of a biofilter with a plastic tarb. Several of these measurements were undertaken in order to evaluate the global gaseous emissions from those sites, to provide data to an environmental technology validation exercise (ETV). Measurement campaigns presented here comprise: comparison of fluxes measurement techniques, calculation of gas fluxes (CO2, CH4, NH3 and N2O) emitted from composting windrows and biofilters, calculation of biogas emission (methane + CO2) before and after a final cover was set on a landfill. Comparisons of the two first chambers have been made since 2007 on several sites (composting of the organic fraction of municipal solid waste or stabilization prior to landfilling). On the first site (non aerated windrows and small mesh) the difference between the measured fluxes was a factor of 2. This factor is rather small: differences between flux measurements using different devices can lead to differences as large as a factor of 100. More recent tests, presented here, show a better agreement: the difference between the two techniques lies within the measurement uncertainty. Comparison of surface air speed measured by two different chimney chambers lead to comparable results. During one experiment, the global air flow interpolated from chamber data was underestimated compared to input flow measurement, because of preferred pathways of the air flow along the wall of the biofilter. When the border effect is correctly taken into account, the total gas flow measured with the chimney chamber and the one measured by a total cover of the biofilter show a good agreement. Biogas surface emissions were measured with the static chamber, on a landfill which receives biologically stabilized waste. This landfill was partly uncovered, so only a part of the biogas was collected and flared. After the final cover was installed, the total biogas flow which was collected and flared was comparable to the sum of (the surface emissions + the collected biogas) without the total cover. The results presented here show that on different sites, different emission measurement methods were used, and that generally there is a good agreement between the methods, providing the care of use are respected. Advantages and care of use for the different methods, depending on the aeration conditions, have been established and some recommendations are given

Comparison of polluting potentials of liquid emissions from MBT plants

International audienceLeachates from two waste management plants which include MBT and an associated landfill have been studied. Leachates have been sampled on different parts of the landfill, and, when possible, process waters have also been sampled. Classical parameters have been measured on all samples and values have been compared: between leachates of the same site, between sites, and to literature values. Leachates show different behaviours depending on the compound: some values are typical of young waste, while others are more representative of old, stabilized wast

Mesures d'air ambiant en conditions de trafic : évolution des COV sur 3 ans

International audienceInfluence of traffic emission on air quality in European cities has widely been studied. Nevertheless, measurement campaigns are usually limited. We present here a set of VOC measurements which has been collected during 5 to 6 campaigns each year over three years. Ambient air is sampled outside vehicles, inside the traffic. Evolution of the concentrations both in urban and rural air over the 3 years are discussed, compound by compound, and compared to data from literature. Influence of traffic on concentrations is obvious. The major fînding is that the concentrations of pollutants related to traffic have been decreasing between 2003 and 2005, specially in urban atmospheres, and in a lesser way, in rural areas.L'influence des émissions liées au trafic automobile sur la qualité de l'air a largement été étudiée. Cependant, les campagnes de mesures sont généralement limitées, dans la durée et le nombre de composés étudiés. Nous présentons ici les résultats d'un ensemble de campagnes réalisées sur une durée de 3 ans, sur plusieurs composés organiques volatils. Le prélèvement est réalisé à l'extérieur de véhicules en roulage, dans la Région Parisienne, en milieux urbain et semi-rural. L'évolution des concentrations au cours du temps est discutée, et les teneurs sont comparées aux données de la littérature. Le fait marquant est la diminution très importante entre 2003 et 2005 des teneurs pour une majorité des polluants, surtout en milieu urbain, et dans une moindre mesure en milieu rural. La diminution de la teneur en benzène des essences, ainsi que l'amélioration des moteurs et le développement des pots catalytiques, explique largement cette tendance

Influence of vehicle traffic reduction in a town centre on BTX pollution

International audienceOn September 22nd 1998, 35 French towns took part in a pilot experiment consisting in drastically reducing the vehicle traffic in the town centres. According to that scheme, INERIS, in association with the local Air Quality Monitoring Network AIRLOR, carried out a BTX sampling campaign over 3 days, in order to quantify the impact of the traffic restrictions on air quality. This campaign was carried out in the centre of Nancy, where traffic restrictions were imposed on an extensive area. Sampling sites were chosen close to the busiest traffic routes. Sampling was carried out using passive samplers, on 10 hours on each day of the campaign. Measurements show clearly that, over the 3 days, the traffic flow reduction led to a decrease in BTX roadside concentrations by between 30 to 80 %. These measurements correlate well with CO levels monitored at one of the sampling sites, and with the volume of traffic in circulation each day. The correlation between BTX and CO clearly indicates traffic as the main source of atmospheric pollution. Measured benzene levels over the 3 days are compared with statutory limit values in France and in Europe

Measurement of persistent organic pollutants in landfill leachates

International audienceLeachates from two landfills which receive the stabilized waste (site A) and sorting refuses (site B) from mechanical biological treatment plants (MBT) have been sampled. Classical parameters, as well as organic persistent pollutants (POPs) have been measured and compared between the two sites, and to data from litterature (classical parameters and POPs) and to limit values for drinking waters, when applicable, for POPs. Though the study was limited to 3 samples, the concentrations in organic micropollutants varied, depending on the compounds and on the treatment process