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

Gaseous emissions reduction from aerobic MBT of municipal solid waste

International audienceSurface gaseous emissions, composition of soil gas and VOC concentration were determined on a French MBT plant, where the biodegradation process is aerobic. Measurements were performed on both the composting windrows and on the landfill cell which receives the sorting rejects. This allowed the comparison of the global methane and CO2 gases, as well as the characterization of the degradation process on the different parts of the site. The performance of the sorting chain allow to obtain a highgrade compost, which can be valorised on agricultural fields, and leads to deposit much smaller quantities of degradable waste than in a classical landfill site, and to lowering seriously the generation of methane. Therefore, landfill gas (LFG) does not need to be recovered and treated by classical means, e.g. flares

Bruno Latour (1947-2022) In Memoriam

International audienc

A stakeholder perspective for analyzing marketing relationships

This paper proposes a framework that enables the application of stakeholder theory to the analysis of marketing relationships. By distinguishing between different types of stakeholder relationships, stretching from the positive to the negative side of relationships (i.e. the ladder of stakeholder loyalty), and describing the various relational factors (i.e. relationship orientation, trust, communication, learning, power, reciprocity and commit-ment) that shape a specific relationship, the proposed framework enables marketers to analyze their firm’s diverse relationships. The paper provides a meaningful starting poin

Odour and Life Cycle Assessment (LCA) in Waste Management: A Local Assessment Proposal

International audienceEnvironmental assessment of municipal solid waste management is essential. Life cycle assessment (LCA) is a powerful and widely used method, which implements causal chains (impact pathways) between the studied processes and their environmental impacts. However, in waste management, the method presents some weaknesses. For example, there is no impact category related to odour, whose assessment is nevertheless essential, especially when the organic fraction of waste is concerned. Odour interferes with human welfare and comfort. Sometimes, it can become a nuisance and be described as a "socio-environmental" impact. To integrate the impact of odour in waste management plans, it is necessary to build an odour-impact pathway. The aim of this paper is to present a first attempt to build such an impact pathway up to the so-called midpoint step (i.e. the level of discomfort to human beings). The methodology we developed is based on the cause/effect chain according to the descriptors of the Site Dependent approach. Unlike classical LCA, the classification step is more important and characterization is aimed at computing the characterization factor. The change in this classification step allows for working on the occurrence of odour impacts. To determine impact occurrence, it is necessary to integrate local conditions into odour assessment. This was done using (1) the USEtox model in which local conditions to assess odour impacts are integrated and (2) the framework of a new methodology that takes into account background concentrations. The methodology was implemented in a case study, i.e. by computing atmospheric emission of ethyl benzene during composting (2.93 × 10−2 kg*day−1). The characterization factor for ethyl benzene was equal to 3.02 × 10−3 kg eq. Benzene per kg emitted ethyl benzene. The daily emission of ethyl benzene generated an odour impact equal to 6.6 × 10−5 kg eq. benzene. With that first odour mid-point impact, we paved the way for the construction of a whole odour pathway (going up to end-point impacts or damages). However, several limits were identified such as data availability, the model under use and the use of average daily data which is less relevant than emission peaks. We should also recall that our methodology is not intended for predicting nuisance likely to disturb populations living nearby the facility. Its first objective is to provide an indicator that fits with LCA methodology in order to help local decision-makers to differentiate waste management scenarios based on exhaustive LCA

Mises au point et vérifications méthodologiques pour la mesure des émissions gazeuses issues des procédés de traitement biologique

Experimentations: flux chamber on waste water treatment plants; comparative assessment of flux chamber, global collection tunnel, tracer gas method, on a composting windrow. Results: very few nitrous oxide coming from the waste treatment process tested (activated sludge); difficulties to obtain representative measures regarding composting because of the high permeability of the compost.Essais réalisés : chambre à flux sur station d'épuration ; évaluation comparative de chambre à flux, tunnel de prélèvement intégral et méthode par gaz traceur sur un andain expérimental. Résultats : peu de protoxyde d'azote produit par le procédé d'épuration investigué (boues activées) ; grande difficulté d'obtenir un prélèvement gazeux représentatif pour le compostage, du fait de la forte perméabilité du compost

Mises au point et vérifications méthodologiques pour la mesure des émissions gazeuses issues des procédés de traitement biologique

Experimentations: flux chamber on waste water treatment plants; comparative assessment of flux chamber, global collection tunnel, tracer gas method, on a composting windrow. Results: very few nitrous oxide coming from the waste treatment process tested (activated sludge); difficulties to obtain representative measures regarding composting because of the high permeability of the compost.Essais réalisés : chambre à flux sur station d'épuration ; évaluation comparative de chambre à flux, tunnel de prélèvement intégral et méthode par gaz traceur sur un andain expérimental. Résultats : peu de protoxyde d'azote produit par le procédé d'épuration investigué (boues activées) ; grande difficulté d'obtenir un prélèvement gazeux représentatif pour le compostage, du fait de la forte perméabilité du compost

Quantification des impacts environnementaux associés au traitemant biologique et à l'utilisation agricole des produits organiques - bilan des connaissances

National audienc

Impacts environnementaux associés au traitement biologique et à l'utilisation agricole des déchets organiques. Bilan des connaissances en vue de l'évaluation environnementale globale des filières

National audienceFace à l'accroissement des exigences sociales et environnementales, les pays européens s'engagent de plus en plus dans une politique de gestion des déchets organiques tournée vers les filières de traitement biologique de ces déchets et leur utilisation agricole. Ces filières de gestion, qui mettent en jeu des phénomènes biologiques et physico-chimiques spécifiques et complexes, demandent encore à être confortées quant à leur coût, leur efficacité et leur impact environnemental. Cet article nous présente ici la démarche et les résultats d'une étude de synthèse bibliographique visant à rassembler les connaissances de base nécessaires à la réalisation d'évaluations environnementales de ces filières

Environmental impacts of biological waste management of organic waste

International audienc