| Environnement, ingénierie & développement |  |
N°40 - 4ème Trimestre 2005
1. Caractérisation des paramètres physico-chimiques et microbiologiques au cours d’un cycle de compostage d’ordures ménagères
Composting is a self-heating, aerobic, biodegradative process of organic waste materials. The present study investigates the prevailing of both physico-chemical conditions such as temperature, total organic matter, moisture, C/N ratio, pH and microbial parameters such as faecal indicator bacteria, Pseudomonas as pathogenic bacteria, mesophilic and thermophilic bacteria, microbial biomass present in a compost of municipal solid waste. So, our results showed the effect of temperature on microbial diversity. In fact, when higher temperature are reached, there is a decrease of faecal coliforms, E.coli, and these results dropped respectively from 370 to 40, from 340 to 25 bacteria/g de MS. The mesophilic microorganisms are very active throughout the process until the end where their number decreased. We also remarked the myriad of microoganisms in the compost showed by the evaluation of the total microbial biomass. Microbial biomass C (BC) ranged from 4,86 to 1 g/kg of dry compost from day 5 to day 62, and decreased and reaches 0,44 g/kg in mature compost.BN showed the same trend as BC ranging from 1,472 to 0,443 g/kg of dry compost from day 5 to day 62. This behaviour is probably related with the decreasing availability of readily decomposable substrates with the ongoing of the process. BC and BN showed a strong correlation (r=0,78). Dynamics of BC/BN ratio, index of the chemical composition of the whole microbial population, suggested a shift in the composition of […]
2. Développement d'un système d'alerte précoce basé sur des bioessais pour la gestion des risques liés aux sites d'enfouissement au Japon
The objections of residents, who suspect that solid waste treatment and disposal facilities emit hazardous substances into surrounding areas, make it difficult to construct and operate these facilities all over Japan. We discuss herein some issues and perspectives regarding the application of toxicity tests to solid waste management, especially to the monitoring of leachate from waste disposal sites. We investigated various toxic potencies and attempted simple scoring of the results for risk management and risk communication to citizens. The data of control experiments and chemical analysis showed that the toxicities observed in leachates weren’t derived from salinity and heavy metals alone. Our scoring results demonstrate the feasibility of a biotest battery for practical use.
3. Etude des émissions dans l’air des traitements biomécaniques aérobies des ordures ménagères
The bio-mechanical treatment of municipal solid waste (BMT) is an increasing option in Europe either as a pre-treatment before landfill or as a pre-treatment before combustion. The present work deals with the problem of assessment of significant data related to emissions to air from BMT. Reliable data are necessary for the development of: a) Life Cycle Assessment studies (LCA); b) verification of compliance with existing regulations; c) environmental impact studies assessment. In order to point out some lack of knowledge about BMTs, some results of a LCA study on MSW bio-stabilization treatment have been reported and analysed. Indeed, during the development of that LCA, some problems were found regarding the availability and the quality of emission data from MSW mechanical biological treatment. Concerning existing regulations, in Europe we can find countries with very different approaches. The studies of the environmental impact assessment of BMT are not still developed as options like incineration. The reason is that the impact of a BMT plant is considered low. On the contrary, it can be demonstrated that attention must be paid in case of not optimised technologies and large plants.
4. Etude comparative de l’adsorption de l’acide 5-sulfosalicylique et des ions orthophosphates en solution aqueuse par des charbons actifs
A study was made of the adsorption of 5-sulfosalicylic acid and orthophosphate ions from aqueous solutions by two commercially activated carbons. Adsorption isotherms obtenained at 298°K were both of Langmuir and Freundlich types and from them adsorption capacities were calculated. From these results, the activated carbon with a pH=8 adsorbs both adsorbates better than the other one (pH=7) and the orthophosphate ions are better adsorbed than the 5-sulfosalicylic acid. These results are comfirmed from theoretical calculations of accessible number of active sites obtained for both the activated carbons. It has also been shown that the percentage dispersion of these active sites is high at the surface. Those results correspond with the number of active sites accessible at the surface.
5. Méthode d’aide à la décision dans le choix d’implantation d’une chaîne de traitement des déchets par incinération avec récupération d’énergie
A methodology of decision-making aid in the choice of a site which can receive a data processing sequence of waste whose principal link is the incineration was elaborate according to a step of the type “risks analysis”. This methodology guided by a protocol of management of project allowed the realization of a tool for. The identification of criteria and of under relevant criteria for which indicators were associated remains the major stage of the process of evaluation of the sites. Each site has a grid of evaluation carried out starting from the data sources. The protocol also integrates other tools such as the multicriterion analysis, which makes it possible to compare the whole of the sites and an analysis of robustness makes it possible to consolidate the choices carried out. The application of the method for the choice of a site was made on 34 sites of the Community of Niort Agglomeration, in the department of Deux-Sèvres. It made it possible to propose to the persons in charge for the study, 6 sites out of 34
6. Éditorial n°40 Déchets Sciences et Techniques: De 1996 à 2006, déjà dix années de parution de la revue Déchets, Sciences et Techniques
La revue Déchets, Sciences et Techniques est arrivée, avec le numéro 40, au terme de sa dixième année d’existence. L’éditorial du premier numéro (janvier 1996), rédigé par Alain Navarro, concepteur de la nouvelle revue, s’intitulait :« Une réponse exclusivement technique au problème des déchets n’est pas suffisante, mais a contrario, la société ne peut en exclure la part nécessaire. »Le contexte de l’époque, dans les premières années de la mise en œuvre d’une politique « déchets » définie par la loi de 1992, faisait apparaître le besoin de travaux scientifiques pour contribuer à l’amélioration indispensable des pratiques en matière de gestion des déchets industriels et urbains. Comme pour toute problématique impliquant très directement l’ensemble de la population, l’organisation de l’articulation entre science et société, entre experts et citoyens, apparaissait comme nécessaire, et la revue a été créée pour répondre à ce besoin. Alain Navarro définissait les « maillons » d’une telle démarche rationnelle : connaissance du système déchets, définition des stratégies et des filières de valorisation et des filières d’élimination, évaluation des impacts, réhabilitation des sites pollués, approches psychologique, économique et juridique. Il définissait ainsi les objectifs de l’implication de la recherche scientifique et les thèmes de la revue, dont le rôle serait de favoriser le lien entre les […]