Analyse et traitement par plasma froid des eaux de rejet de « l’abattoir des Brasseries » à Yaoundé

Des echantillons des eaux usees de á lfabattoir des Brasseries â a Yaounde, preleves ont ete analyses et traites par plasma froid. Les resultats dfanalyse revelent que lesdites eaux sont basiques (pH = 8.65), tres conductrices (conductivite electrique = 1625 ƒÊScm-1), fortement polluees (DBO5 = 1000 mgL-1 dfO2, DCO = 2390 mgL-1 dfO2 et 200 mgL-1 dfammonium) et biodegradables (DBO5/DCO = 0.42). La teneur elevee en chlorures (1347 mgL-1) et lfabsence des metaux lourds ont ete notees. Apres traitement par plasma, on observe une reduction de 50% de la DBO5 en 10 minutes, le debit du gaz plasmagene etant fixe a 1000 Lh-1. Lfefficacite du plasma froid a decharge electrique rampante (glidarc) a ete une fois de plus prouvee pour la reduction de la pollution environnementale.Mots cles: Eaux usees, biodegradables, glidarc, pollution

Impact du déversement direct des eaux usées et de drainage dans la nappe libre de l'Oued Souf et son influence sur la qualité des eaux souterraines.

Ces vingt dernières années la région de l'Oued Souf souffre du phénomène de la remontée des eaux de la nappe libre, qui inonde les « ghouts » et les maisons, entrainant de graves problèmes sociaux, agriculturaux et environnementaux. Le réseau d'assainissement qui ne couvre qu'une partie de la ville d'El-Oued rend la situation plus dramatique. Jusqu'a la fin de l'année 2010 une zone, située au Nord-Est de la ville d'El-Oued, a été aménagée pour que les eaux de drainage (système pour rabattre la nappe) et les eaux usées soient déversées directement sans aucun traitement préalable. L'objectif de cette étude est de déterminer l'extension du déversement dans la nappe libre de l'Oued Souf, surtout des eaux usées, et d'évaluer les risques de pollution des eaux souterraines de la nappe libre, plus particulièrement dans la zone de rejet. Six campagnes de mesures hydrochimiques ont été faites : trois durant l'année 2007 (avril, juin et septembre), deux durant l'année 2010 Ganvier et avril) et une en mai 2012 âpres l'arrêt de rejet. L'analyse des échantillons et leur interprétation ont permis l'établissement d'une carte de l'indice de pollution organique. Cette dernière a montre que le terrain a un pouvoir autoépuratoir élève ce qui réduit considérablement les effets de la pollution d'origine organique. Cette tendance est confirmée par les valeurs de la dispersivité longitudinale αL faibles, déterminées au niveau de la zone de rejet. Pour ce qui est des teneurs de certains éléments majeurs naturels (Na+, Ca++, SO4-, Cl-...), celles-ci restent élevées et posent un sérieux problème d'aptitude de ces eaux à l'Irrigation.Mots clés: Nappe libre - Remonte des eaux - Eaux usées - Pollution organique - Oued Souf More than twenty years the region of Oued Soufis suffering from the rising of the water table in the unconfined aquifer, causing flooding of "ghouts" and damaging houses, which induces serious social, agricultural and environmental problems. The sewerage system that covers only a part of the city ofEl-Oued makes the situation more dramatic. Until the end of 2010, the drainage water and wastewater are discharged directly without any preliminary treatment in an area located north-eastern of El-Oued city. Nowadays a wastewater treatment plant was constructed and this area is not more used. The purpose of this study is to determine the extension of the contaminated area by discharged wastewater in the unconfined aquifer and to assess the risk of pollution of groundwater, particularly in the discharging zone. Three hydrochemical surveys were conducted in the discharging area and in its vicinity during 2007 (april, june and september), two during 2010 Ganuary and april) and one in may 2012. The interpretation of analysed samples shows that the pollution has a very short extension and the soil has an important self purifying role that reduces the effects of organic pollution that is shown in the established map of index of organic pollution. The low value of longitudinal dispersivity αL of the soil, evaluated in the discharging area, confirms this trend. We note that the content of some major natural elements such as (Na+, Ca++, SO4-, Cl-...) is high and the use of the groundwater is not advised for irrigation.Keywords: Unconfined aquifer- Rising water level - Wastewater- Organic pollution - Oued Sou

A regional water quality model designed for a range of users and for retrofit and re-use

We discuss the motivations for, and software design concepts underpinning, the development of a regional water quality model. The Environmental Management Support System (EMSS) was developed to predict daily fluxes of runoff, total suspended sediment, total nitrogen and total phosphorous through a large-scale river network. It was built using a custom environmental modelling framework called Tarsier, founded on the Borland C++ Builder rapid application development environment. Three autonomous models are integrated within the EMSS, but are loosely coupled so that alternative models could be retrofitted into the system if desired. The three models share common data handling and visualisation routines resident in the Tarsier modelling environment and used in other modelling applications. The EMSS was designed for use by a range of stakeholders with varying levels of computer and technical proficiency. To satisfy their varying needs, we built three different interfaces, suited to ‘expert’, ‘intermediate’ and ‘basic’ users. The interfaces for the latter two groups were developed using interface prototyping methods, resulting in software that suited the user requirements. The object-oriented design employed in the coding of the EMSS has enhanced the extendibility and re-useability of the software. The EMSS development was part of a larger hydrologic modelling initiative aimed at reducing duplication in model building and standardising approaches to model design and delivery. The lessons learned during development of the EMSS have informed our future model development strategy

Sisyphe dans la ville

International audienceL'exemple de Besançon montre comment la municipalité est conduite à prendre toujours d'avantage en charge la réalisation de la propreté urbaine face à des citadins réticents à manier le balai hors de l'espace privé. Ce service municipal s'est professionnalisé et mécanisé. Que ce soit dans l'aménagement des réseaux d'eau, d'égouts, de collecte de déchets, la tendance à l'égalité l'emporte. Mais elle coûte cher, et exige aujourd'hui une attitude d'épargne en amont

Research Perspectives: Through Whose Eyes? The Critical Concept of Researcher Perspective

In this article, we explore the notion of “researcher perspective,” by which we mean the viewpoint from which the researcher observes phenomena in any specific research context. Inevitably, the adoption of a particular viewpoint means that the researcher privileges the interests of one or more stakeholders while downplaying the interests of other stakeholders. Preliminary empirical analysis of a corpus of 659 articles published in three separate years in the AIS Basket of Eight journals, undertaken in preparation for the present paper, revealed that around 90% of articles (1) adopted a single-perspective approach, (2) were committed solely to the interests of the entity central to the research design, and (3) considered only economic aspects of the phenomena investigated in the research. Taken together, we argue that these three characteristics are unhealthy for the discipline and are likely to lead to the neglect of important research opportunities. We suggest that the principle of triangulation be applied not only to data sources and research methods, but also to researcher perspectives and that a consequent broadening of the IS discipline’s scope is essential. We conclude the article with prescriptive recommendations for the practice of research that is relevant to multiple stakeholders

Liability of Public Officer for the Loss of Private Funds Entrusted to His Keeping

There is much contrariety of decision concerning the liability of public officers for the loss of funds with which they have been entrusted. A recent case illustrates some of the more important phases of the law of such a situation. People for use of Hoyt et al. v. McGrath et al. (Ill. 1917), I17 N. E. 74. In this case the public brought an action of debt on the official bond of the clerk of court for the use of Hoyt and others. Usees had tendered into court a sum of money which the clerk took under the court\u27s order to receive and hold it, but refused to pay it over to the usees as directed by a later order of the court, claiming the money had been received by him in his individual capacity and had been lost without his fault by the failure of the bank in which it had been deposited. Held, that as a public officer is liable as an insurer for private funds received by virtue of his office, the failure of the clerk to pay over the money in question constituted a breach of his official statutory bond

The Emerging Nature of Participation in Multispecies Interaction Design

Interactive technology has become integral part of daily life for both humans and animals, with animals often interacting with technologized environments on behalf of humans. For some, animals' participation in the design process is essential to design technology that can adequately support their activities. For others, animals' inability to understand and control design activities inevitably stands in the way of multispecies participatory practices. Here, we consider the essential elements of participation within interspecies interactions and illustrate its emergence, in spite of contextual constraints and asymmetries. To move beyond anthropomorphic notions of participation, and consequent anthropocentric practices, we propose a broader participatory model based on indexical semiosis, volition and choice; and we highlight dimensions that could define inclusive participatory practices more resilient to the diversity of understandings and goals among part-taking agents, and better able to account for the contribution of diverse, multispecies agents in interaction design and beyond

Nuisances olfactives en station d'épuration des eaux : méthodologie de caractérisation des émissions

International audienceLe probleme des nuisances olfactives generees par les ouvrages d'epuration des eaux usees se pose de plus en plus souvent, en particulier en raison du developpement de l'urbanisation qui entraine un rapprochement inevitable entre les zones habitees et les sites d'implantation des stations d'epuration. Les differentes etapes d'epuration de l'eau et de traitement des boues conduisent pour la plupart a la formation de molecules volatiles malodorantes qui se dispersent plus ou moins rapidement dans l'atmosphere