Compostage et qualité du compost de déchets urbains solides de la ville de Bobo-Dioulasso, Burkina Faso

Composting and Compost Quality of Urban Solid Wastes in Bobo-Dioulasso Town, Burkina Faso. A study of urban solid wastes composting was conducted to evaluate wastes compost quality. Wastes of municipal dumps of Bobo-Dioulasso have been collected, separated and composted with cow manure, grass and Kodjari phosphate rock. During composting the pH increased up to 8.6, the moisture up to 68% and the temperature up to 65 °C before decreasing and then stabilizing at 7.1; 30% and 31 °C respectively. Particle size distribution of composts showed that the fraction ≤ 2 mm is dominant, about 65%. The organic matter, C, N, P and K contents of the composts are acceptable but the C/N ratio was relatively low in comparison with international standard. The heavy metals (Cu, Pb, Ni and Zn) contents in composted urban wastes were relatively high with higher content of Zn and Pb. The compost obtained was of good quality and the addition of Kodjari phosphate rock enhanced this quality

Production of bio-gas (In urban areas using different types of wastes)

The focus of the research paper is to investigate the importance of biogas as an alternative energy sources in urban area. Urban waste, including wastewater treatment plants, food waste from households and businesses, yard clippings, human wastes, vegetable market wastes, and non-recyclable paper, will create biogas under the right conditions. Food waste from grocery stores, restaurants, cafeterias and homes contains energy and valuable nutrients. These wastes of specific area should collect in single tank and use them in bio-gas production

Solid Wastes, Poverty and the Environment in Developing Country Cities

Many cities in Africa, Asia, and Latin America face serious problems managing their wastes. Two of the major problems are the insufficient collection and inappropriate final disposal of wastes. Despite spending increasing resources, many cities – particularly in Africa and Asia – collect less than half of the waste generated. Most wastes are disposed of in open dumps, deposited on vacant land, or burned by residents in their backyards. Insufficient collection and inadequate disposal generate significant pollution problems and risks to human health and the environment. Over one billion people living in lowincome communities and slums lack appropriate waste management services. Given the rapid population growth and urbanization in many cities, the management of wastes tends to further deteriorate. This paper examines the challenges and opportunities that exist in improving the management of waste in Africa, Asia, and Latin America. It is argued that, despite a worsening trend, there are opportunities for reducing pollution, alleviating poverty, improving the urban environment, and lowering greenhouse gas emissions in developing countries by implementing low-cost, low-tech, labour-intensive methods that promote community participation and involve informal refuse collectors and waste-pickers. Evidence from several cities in Africa, Asia, and Latin America is discussed.urbanization, cities, environment, waste

Sustainable valorisation of organic urban wastes : insights from African case studies

Understanding the problems and potentials of the organic waste stream is perhaps the single most important step that city authorities in Africa could take in moving towards sustainable, affordable, effective and efficient waste management. This publication presents four examples of recent attempts to manage organic waste sustainably in the African context. The participants in the ‘Nairobi organic urban waste’ project have structured this case exercise in order to use the case studies as object lessons, to harvest genuine insights into the feasibility of a variety of ways to successfully and sustainably valorise urban organic waste streams. Three contemporary case examples of compost production are presented. These include composting by a community-based organisation in the Kenyan private sector and by a public-private partnership in Malawi. In all three cases, the project and case study focus is on the relations between city waste and the agricultural supply chain. A fourth case study describes the technical and economic potential to produce and use biogas from urban organic waste

Future Projections of Urban Waste Flows aand their Impacts in African Metropolises Cities

This paper presents future trends of urban wastes and their impacts on the environment of African cities using plausible mitigation scenarios. To accomplish this, an integrated dynamic model for urban waste flows was developed, tested, calibrated and validated. Its parameter sensitivity was analyzed. Using population projection up to 2052 with different levels of technological implementation, policy enforcement and awareness raising, four runs were executed. The “business as usual” run showed that with no additional mitigation measures, the environmental quality in Kampala and Dar es salaam Cities deteriorates. The “more enforcement” and “more collection” scenarios showed good reduction in environmental loads but they perform less well in resource recovery. The “proper management” scenario that combines enhanced technological implementation, awareness raising and policy enforcement, produced the smallest environmental loads, and recovered the largest amount of resources. Thus, the city authorities, general public, community based organisations and Non-governmental organizations would have to increase their efforts in finances and commitment to improve the urban environmental quality and increase resource recovery

Modelling agronomic properties of Technosols constructed with urban wastes

International audienceThe greening of urban and suburban areas requires large amounts of arable earth that is a non-renewable resource. However, concentration of population in cities leads to the production of high amounts of wastes and by-products that are nowadays partly recycled as a resource and quite systematically exported out of urban areas. To preserve natural soil resources, a strategy of waste recycling as fertile substitutes is proposed. Eleven wastes are selected for their environmental harmlessness and their contrasted physico-chemical properties for their potential use in pedological engineering. The aim is (i) to demonstrate the feasibility of the formulation of fertile substrates exclusively with wastes and (ii) to model their physico-chemical properties following various types, number and proportions of constitutive wastes. Twenty-five binary and ternary combinations are tested at different ratios for total carbon, Olsen available phosphorus, cation exchange capacity, water pH, water retention capacity and bulk density. Dose-response curves describe the variation of physico-chemical properties of mixtures depending on the type and ratio of selected wastes. If these mixtures mainly mimic natural soils, some of them present more extreme urban soil features, especially for pH and P Olsen. The fertility of the new substrates is modelled by multilinear regressions for the main soil properties

Development of organic fertilizers from food market waste and urban gardening by composting in Ecuador

Currently, the management of urban waste streams in developing countries is not optimized yet, and in many cases these wastes are disposed untreated in open dumps. This fact causes serious environmental and health problems due to the presence of contaminants and pathogens. Frequently, the use of specific low-cost strategies reduces the total amount of wastes. These strategies are mainly associated to the identification, separate collection and composting of specific organic waste streams, such as vegetable and fruit refuses from food markets and urban gardening activities. Concretely, in the Chimborazo Region (Ecuador), more than 80% of municipal solid waste is dumped into environment due to the lack of an efficient waste management strategy. Therefore, the aim of this study was to develop a demonstration project at field scale in this region to evaluate the feasibility of implanting the composting technology not only for the management of the organic waste fluxes from food market and gardening activities to be scaled-up in other developing regions, but also to obtain an end-product with a commercial value as organic fertilizer. Three co-composting mixtures were prepared using market wastes mixed with pruning of trees and ornamental palms as bulking agents. Two piles were created using different proportions of market waste and prunings of trees and ornamental palms: pile 1 (50:33:17) with a C/N ratio 25; pile 2: (60:30:10) with C/N ratio 24 and pile 3 (75:0:25) with C/N ratio 33), prepared with market waste and prunings of ornamental palm. Throughout the process, the temperature of the mixtures was monitored and organic matter evolution was determined using thermogravimetric and chemical techniques. Additionally, physico-chemical, chemical and agronomic parameters were determined to evaluate compost quality. The results obtained indicated that all the piles showed a suitable development of the composting process, with a significant organic matter decomposition, reached in a shorter period of time in pile 3. At the end of the process, all the composts showed absence of phytotoxicity and suitable agronomic properties for their use as organic fertilizers. This reflects the viability of the proposed alternative to be scaled-up in developing areas, not only to manage and recycle urban waste fluxes, but also to obtain organic fertilizers, including added value in economic terms related to nutrient contents.Peer ReviewedPostprint (published version