Gestion des déchets ménagers dans le quartier Mambanda (Douala-Cameroun) : Quelles stratégies durables?

L’urbanisation est l’une des grandes caractéristiques du monde contemporain. Elle génère des effets sur l’environnement et le cadre de vie perceptibles à travers la gestion des déchets. En effet, l’urbanisation s’accompagne d’une croissance de la population urbaine qui à son tour induit une production sans cesse importante de déchets, souvent mal gérés. Cette réflexion vise à cerner les problèmes liés aux différentes pratiques de gestion des déchets ménagers dans le quartier Mambanda de la ville de Douala. L’étude s’appuie sur une approche à la fois qualitative et quantitative qui intègre les recherches documentaires, les observations de terrain et les entretiens avec les acteurs-clé du terrain. Les résultats de l’étude montrent que les déchets solides, liquides et gazeux produits dans le quartier Mambanda sont constitués essentiellement des restes de nourriture, d’eaux usées domestiques et résiduaires, des eaux vannes, des déjections humaines et animales… Les populations, l’Etat et les sociétés privées (Hysacam, CIPRE, associations…) sont les acteurs qui se déploient sur le terrain pour gérer ces déchets qui sont généralement déversés dans les rues, les caniveaux, les cours d’eaux, les champs, les drains et les bacs à ordures. La mauvaise gestion des déchets entraine, dans la plupart des cas, la dégradation de l’environnement et du cadre de vie des populations et par conséquent impacte la santé des populations qui y vivent. Ainsi, la forte implication des populations dans le processus de gestion des déchets (campagnes d’éducation à l’hygiène, création et entretien du réseau d’évacuation…) est la meilleure stratégie durable pour une gestion efficace de ces déchets. Urbanization is one of the great characteristics of the contemporary world. It generates perceptible effects on the environment and the living environment through waste management. Indeed, urbanization is accompanied by a growth of the urban population which in turn induces an ever-increasing production of waste, which is often poorly managed. This reflection aims to identify the problems related to the different household waste management practices in the Mambanda district of the city of Douala. The study is based on a qualitative and quantitative approach that integrates documentary research, observations and interviews with key players in the field.The results of the study show that the solid, liquid and gaseous waste produced in the Mambanda district consists mainly of food scraps, domestic and waste water, human and animal excreta. The populations, the State and private companies (Hysacam, CIPRE, associations, etc.) are the actors who are deployed in the field to manage this waste which is generally dumped in the streets, gutters, rivers, fields. , drains and garbage bins. Poor waste management leads, in most cases, to the degradation of the environment and the living environment of the populations. Thus, the strong involvement of the population in the waste management process (hygiene education campaigns, creation and maintenance of the disposal network, etc.) is the best sustainable strategy for effective waste management.

Aerotechnogenic Pollution of Boreal Forests in Northern Europe

This paper discusses the changes that boreal forest ecosystems undergo under the influence of gaseous waste from the processing of non-ferrous ores on the Kola Peninsula. These communities are represented primarily by pine forests growing on the northern border of their range. The main forest-forming species here is Scots pine main components for this local aeronautical emission are polymetallic dust and sulfur dioxide, which is the main by-product during the roasting of sulfide and polysulfide ores. The studies were carried out on the basis of materials obtained at 6 sample plots located at different distances from the pollution source. As a result, an exponential increase in the content of heavy metals in the soil, as well as in the assimilatory organs of the components of these communities, was shown when approaching the source of pollution (this pattern is different for each of the metals). Regularities of negative changes in the structure of some components of plant communities, such as phytomass, projective cover of the lower layers, and the vital structure of the tree layer were also identified.

Improvement of the method of purification of exhaust gases in the production of asphalt concrete

The article analyzes the air protection measures of LLP «Asphaltbeton» demonstrated the disadvantages of the efficacy of the purification system for calculating waste emissions and scattering of atmospheric contaminants, as the concentration of sludge substances (dust) is 2.5 times more than 1.206 mg/m3, and nitrogen, the concentration of carbon dioxide and the amount of hydrocarbons in the sanitary dimensions and according to it. The effectiveness of purification of exhaust gas from the asphalt mixer D-645 with the CF-10 chain filter allowed the choice of more systems. The calculations in the FTS-10 showed that it is possible to efficiently clean gas emissions from 95% to 95% by removing the waste from gaseous waste. When preparing asphalt concrete, harmful substances such as dust, oxides, nitrogen and carbon, hydrocarbon are distributed. Therefore, the permissible threshold for all hazardous waste recycling sites has been identified (DHM, mg/m3), which prevents the dust, steam, gas workers from exposing the flu or fluid to the workplace while maintaining a working life of less than 8 hours per day.

Composting treatment of fur waste originating from tannery

The tanning industry generates effluents with a high contaminant load represented in a considerable amount of liquid, solid, and gaseous waste. Solid waste, such as residual hair, fat, and meat, are dumped directly in landfills, triggering serious environmental problems. The objective of this research was to compost this waste, previously desulfurized, in a mixture with remnants from pruning as a bulking agent. This low-cost strategy may reduce the total amount of waste. A composting pile was created using residual hair and pruning remnants in a proportion of 3:1 (w/w) and then an inoculum was added. The waste degrading process ran for 141 days, followed by a maturation period of 64 days. Throughout the process, the temperature, moisture, pH, and electrical conductivity (EC) were monitored. The highest temperature reached was 69.7°C, which secured good disinfection. The EC was 0.27 dS/cm, having lower values than Spanish regulations, possibly due to the salt removal over the irrigation periods. The organic matter content decreased continuously, to reach an endpoint of 42%; this result agrees with the high organic matter content of the tannery waste and the pruning remnants. Germination index was 43.55%, which indicates the presence of phytotoxic substances. As compared to the initial value (10.73%) there was partial degrading of these substances. The challenge is to improve this parameter by identifying new mixtures and adding efficient microorganisms that help to degrade phytotoxic substances.

Methodical Approaches to the Identification of Gaseous Production Waste that in a Negative Effect Affect Macroeconomic Processes

The negative externalities caused by gaseous production waste are quite dynamic, so they need additional study in order to find tools for their internalization. Negative externalities are currently not sufficiently studied, the question of assessing the degree of impact of gaseous production waste on macroeconomic processes remains little studied. The aim of the work is to scientifically substantiate methodological approaches to the detection of gaseous production waste that negatively affects macroeconomic processes. A methodology for identifying production wastes that negatively affect macroeconomic processes is proposed. It is based on an analytical approach that will summarize the information obtained using statistical methods and methods of in-depth data analysis. Grain and sunflower yields were chosen as a target for detecting the impact of gaseous waste. The input factors are the most common elements of gaseous production waste, namely: carbon monoxide (CO), methane (CH4), nitrogen dioxide (NO2), nitrogen oxides (NO), soot, sulfur dioxide (SO2), non-metallic light organic compounds, carbon dioxide (CO2). The methodology for determining the degree of impact of production waste on macroeconomic processes in Kharkiv, Dnipropetrovsk, Zaporizhia, Poltava and Sumy regions of Ukraine has been tested. According to the results of analytical generalization, the degree of influence of the most common elements of gaseous production waste is estimated. The results of the analysis for sulfur dioxide (SO2) and soot are informative. The obtained evaluation results should become the basis for the development of a model of internalization of negative externalities. A promising area of further research is the testing of this methodology in relation to all sectors that are potential recipients of negative effects arising from emissions of gaseous production waste.

Sustainable Development of a Peripheral Mountain Region on the State Border: Case Study of Moravské Kopanice Microregion (Moravia)

The sustainability of rural areas is considered to be most threatened in peripheral, hardly accessible microregions with insufficient economical sources. The paper analyses one such rural area in the eastern part of Moravia from the viewpoint of individual economic, social, and environmental sustainability pillars. The area under study is the mountain territory on the border with Slovakia, which is under large-scale landscape protection. The area with very limited economic sources has been impacted with a change to the geopolitical situation after 1993 (from the centre of Czechoslovakia to the fringe of Czechia). It was stated that the environmental pillar is in the best of conditions; however, perhaps threatened with missing technical infrastructure in relation to the disposal of solid, liquid, and gaseous waste, the social pillar is improving in relation to the post-productive transition, whereas the economic pillar is the most fragile because of its dependence on exogenous jobs in surrounding towns. In general, the microregion seems to be sustainable at the moment. Long-term sustainability will depend on the general economic, demographic, and climatic development of the country and Europe.