Biowaste separate collection and composting in a Small Island Developing State: The case study of São Tomé and Principe, West Africa

Abstract

São Tomé and Principe archipelago in West Africa is a Small Island Developing State facing acute waste management problems. This article describes the implementation of selective collection of biowaste combined with composting in São Tomé, as a case-study of an innovative action in the framework of a Small Island Developing State. Collection was designed to gather 225 t y(-1), targeting non-domestic biowaste producers, namely local businesses, municipal markets and municipal green waste. A municipal composting plant was built using basic facilities and windrow composting. The total investment amounted to €50,000, mainly supported by external aid. Biowaste producers reacted very positively, source segregating enthusiastically. Irregular service - collection collapsed each time the old vehicle was repaired - together with political disengagement and unmotivated work force were the major constrains. Biowaste was intermittently delivered to the composting plant and yielded 2 t of compost from July to December 2013 and 10 t during 2014. Compost was sold as organic fertiliser to a touristic resource, to small farmers and to gardeners, at a market price slightly below production costs, meaning the process is not economically sustainable without support. Nevertheless, biowaste is one of the few waste fractions (other than glass) that can be turned into a product that has both market value and a real demand, showing the enormous potential of composting source-separated biowaste in this part of the world.

Formal and informal waste selective collection in developing megacities: Analysis of residents’ involvement in Bolivia

“…Recyclable waste selective collection (SC) is imperative for reducing environmental impacts and boosting waste recycling and recovery (De Feo et al, 2019a; Hahladakis and Aljabri, 2019; Ionescu et al, 2015; Rada et al, 2018). However, its implementation is a challenge in low–middle income countries: low economic level (Gallardo et al, 2018), lack of legislation and poor administrative logistic (Gallardo et al, 2012), low interest of the political leadership, lack of appropriate infrastructure (Vaz et al, 2015), low-level technology (Chu et al, 2016) and widespread environmental issues (Ibáñez-Forés et al, 2017) are problems that should be overcome for introducing waste SC systems (SCS). More difficult is the application of SCS in developing megacities, due to the high urbanization rate, lack of urban planning, differences among the neighbourhoods of the city (Wilson et al, 2012), and the presence of the informal sector (IS)(Kasinja and Tilley, 2018).…”

Organic waste valorization in remote islands: Analysis of economic and environmental benefits of onsite treatment options

“…Therefore, population involvement is the first step to plan effective AD and composting plants, achieving positive results in terms of collection and treatment efficiency. For example, the implementation of OF selective collection combined with composting in São Tomé ( Vaz et al, 2015 ) shows how the local population accepted the system, providing uncontaminated and well segregated biowaste to feed the treatment plant, resulting in an efficient AD treatment. Awareness campaigns aimed at achieving the expected separate collection standards should be organized in order to start planning appropriate AD treatment systems in remote areas; it represents another recommendation that decision makers should consider.…”