| Environnement, ingénierie & développement |  |
N°83 - mars 2020
1. Éditorial n°83 Déchets Sciences et Techniques
Riche de près d'un quart de siècle d'existence, dans la fleur de l'âge donc, la revue DST va aborder une nouvelle phase dans son existence.Je vous l'annonçais en effet dans mon édito du n°82, l'INIST, qui héberge et diffuse DST sur sa plateforme I-Revues, a décidé d'arrêter son service de diffusion en libre accès. Cette situation que nous regrettons nous impose de trouver une autre plateforme de diffusion. Plusieurs options été étudiées et les choix définitifs n'ont pas encore été faits. Le partenariat avec une nouvelle plateforme de diffusion sera établi dans les semaines ou mois qui viennent. Nos auteurs et lecteurs seront bien évidemment informés du futur dispositif dès que le choix sera arrêté. Nous avons décidé de profiter de cette situation contrainte pour saisir l'opportunité de faire évoluer la revue. Le champ thématique et le titre de la revue vont probablement être modifiés pour mieux correspondre aux enjeux actuels des sciences et génie de l'environnement, dans cette période de transitions déterminante pour l'avenir de nos sociétés. Mais la préparation de l'avenir de la revue n'empêche pas, bien au contraire, de goûter le temps présent. Voici donc ce qui sera probablement le dernier numéro de la revue dans sa version actuelle.Bonne lecture. Je vous donne rendez-vous dans quelques mois pour la parution du premier numéro de la revue dans sa nouvelle configuration. […]
2. Validation d’une méthode de valorisation matière et énergie des huiles de vidange
More than 22,500 tons per year of waste lubricating oil are non-regulatory managed in Cameroon. They are burned in very dangerous conditions when they are not simply dumped in nature. Yet, these wastes are classified as very dangerous for human-beings. The aim of this work is to promote safer methods of disposal of waste lubricating oil in Cameroon by stressing on materials recovery and energetic valorisation in a steam boiler. A combined method of action of melted salt, distillation under low pressure and treatment on activated adsorbed earth (ASFDPRTTA) is efficacious for the task. The oil, treated by this method strips it of polluting chemical in order to obtain a fuel (ecofuel) meeting up the energetic and environmental expectations as required by standards. On the other hand, the fuel presents physicochemical features nearest to the ones of gasoil so that it has been used in a gasoil steam boiler without risk. Also, the fuel served as a base for the regeneration of a new lubricant (envilub) by adding additives in suitably chosen proportions. Our method is using a low cost investment, simple equipment at the point where inexperienced staff with a minimum of training can master it. It also permits job employment opportunities as well as environmental preservation.
3. Quelle gestion pour une prise en charge efficiente des déchets d’activités de soins à risques infectieux en Algérie ? Cas d’Azzaba
Algeria’s economic and social development has generated a significant amount of special waste. Despite the efforts made and the legislative texts promulgated, their management and treatment are difficult. The production of these harmful materials has become a source of problems not only of insalubrity but also of public health. Indeed, the shortcomings in the management of these special residues produced contribute globally to a degradation of the environmental quality and more precisely to a visual pollution, olfactory as well as to potential impacts on the human health. Faced with this situation and in order to minimize the environmental and health risks, a more rigorous and more rational treatment of Infectious Risk Care Activity Waste (IRCAW) is essential for all stakeholders. The purpose of this article is to try to identify the impact of this Special Waste on human health and the environment in Azzaba, a small town in eastern Algeria. This city has experienced and knows a strong demographic and economic development accompanied by a greater sanitary coverage (implantation of hospital, centers of health and care ...). At the end of the study, courses of action for Sustainable Management of IRCAW are discussed.
4. Gestion des déchets ménagers dans la ville de Kinshasa : Enquête sur la perception des habitants et propositions
In the city of Kinshasa, waste generation in 2016 is estimated at 5,600 tonnes per day (Lelo Nzuzi, 2008), 16,800 tonnes/month and 2,016,000 tonnes per year (Holenu Mangenda H., 2016). This waste is produced by an estimated population of more than 12,000,000, with an area of the city of 9,965 km2. The results of this study were obtained from field surveys and interviews carried out in the communes of the city of Kinshasa, that is to say 22 communes, and among the actors working in the field of waste management. These results show that the main cause of the pervasiveness of uncontrolled landfills is the indiscipline of the population, and in terms of collection, there is the inefficiency of state services on the ground. Contrary to international standards on landfill management, the population of the city of Kinshasa daily discards waste in unauthorized places with harmful consequences on the environment and on the health of the population. The management system that is proposed must follow the system "RVM" (Reduction, Valuation and Landfilling), this system recommends in a first place the reduction of waste, that is to say, the waste must be exempted before proceeding to the recovery stage so that the proposed final landfills no longer receive excessive volumes of waste. This approach will not only combat pollution caused by the effects of wild landfills, but also combat climate change and mitigate warming due to greenhouse gases.
5. Lecture de la dynamique territoriale à Douala et son impact sur la gestion des déchets solides ménagers par la théorie de la formation socio-spatiale
Since the 1970s, almost all states in the world have realized the need to integrate the sound management of waste, including solid household waste into their national and local environmental policies. This environmental awareness has been the result of the evolution of several environmental events around the world. It materialized in Rio de Janeiro in 1992 with the establishment of "Agenda 21" which devoted its Chapter 21 mainly to the environmentally sound management of waste. The signatory states of the Rio deeds, including Cameroon, were at the same time committed to integrating into their internal environmental policies, mechanisms and strategies for the rational and sustainable management of household waste. Therefore, one can wonder why, several years after Rio, despite these commitments, threats related to the mismanagement of waste persist in African countries and precisely in Douala ? This research aims to rely on the Guy Di Meo’s theory of the “formation socio-spatiale” to highlight the territorial dynamics of Douala in relation to solid household waste management. The data presented here come from field observations, surveys and interviews with resource persons and the consultation of documents related to the subject. The article highlights the territorial dynamics of Douala and the factors that favor the emergence of household waste management practices that seem unsuited to the urban space. It also insists on the degree of responsibility of the […]
6. Étude des propriétés physico-mécaniques d’un béton hydraulique contenant des cendres de coques d’anacarde de tailles micrométriques et nanométriques substituant partiellement le ciment
The use of waste as an alternative resource is an approach to reduce pressure on natural resources, as well as the environmental iMPacts associated with waste disposal, if recycling is conducted under environmentally friendly conditions. The objective of this study is to determine the conditions for incorporating pyrolysis ash from cashew nuts shells into concrete as a partial replacement for cement. The ashes used were collected from Afonkanta Benin Cashew, one of the plants that processes cashew nuts into almonds. The various ash additions replace the amount of cement added to the concrete, gradually in proportions of 5 %, 10 %, 15 %, 15 %, 20 % and 25 % ash. The related physico-mechanical characteristics, namely compressive strength, tensile strength, hydraulic conductivity and subsidence of the concrete over time, have been determined. The physico-mechanical results show that the best characteristics of the hydraulic mixture were obtained with the proportion of 15 % of ash. Indeed, a hydraulic concrete mixture of 15 % ash at 28 days of maturity gives a compressive strength of 51.83 N/mm2, a tensile strength of 13.65 N/mm2, a low hydraulic conductivity value of 3.48 10-17m/s. There is also an average subsidence of 3 mm.