Waste composting for urban and peri-urban agriculture: Closing the rural-urban nutrient cycle in Sub-Saharan Africa

One of the greatest future challenges for governments all over the world will be the provision of nutritional and affordable food for expanding urban populations. On a global scale urban settlements consume currently 70-80% of all resources. This centralized consumption results in problems at both ends of the food chain: soil nutrient mining in agricultural production areas and pollution and waste disposal problems in urban centers. Increasingly, municipal authorities are viewing the recycling of nutrients from organic waste through solid waste management schemes. In this way, the costs of waste management/disposal can be reduced and the nutrient cycle closed, to the benefits of urban and peri-urban farmers. This requires an integrated and multidisciplinary approach that considers the different technical options and their economic feasibility, as well as the administrative framework and socio-cultural and environmental issues. Farmers perception of the waste product as a benefit is as important as the potential contamination of the compost with heavy metals. All these aspects are discussed in this publication supplemented and illustrated with examples and case studies, mostly from Africa. IWMI (formerly IBSRAM) and FAO are pleased to present this joint publication as a contribution to the discussion of these important issues.