Compost quality from biowaste treatment in West Africa

• Autor(a) principal: Vaz, João Miguel
• Data de Publicação: 2015
• Outros Autores: Ferreira, Célia, Pečkytė, J., Tumaševičiūtė, R.
• Idioma: eng
• Título da fonte: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Texto Completo: http://hdl.handle.net/10400.2/14334
• topic: Compost; Composting; São Tomé e Principe; Biowaste; Nutrients; Waste management in Africa

Composting is generally considered as a cost effective waste management option for stabilising waste and produce a soil improver/organic fertilizer. Passive aerated open windrows is a typical low cost option feasible in in São Tomé and Principe (pop. 197 900), a small island state in West Africa. Here the European Union, in partnership with Instituto Camões, UCCLA and the local authority, invested in the waste management system upgrade. A composting plant integrated with biowaste collection has been working since 2013. In order to assess the composting process efficiency, a novelty in São Tomé on this scale, temperature was regularly measured and registered. The matured compost was analysed in Portuguese Laboratories, targeting parameters such as: humidity, pH, electrical conductivity, organic matter, macronutrients and heavy metals. The results are encouraging suggesting that composting is a good option for treating biowaste collected separately at households, central markets, supermarkets, rest homes, restaurants, municipal gardens…etc. Compost output has high C/N ratio and concentration of organic matter, thus evidencing agronomic value. However, some heavy metals (Cr, Ni) content are a matter of concern, and require further assessment in order to prevent their presence. Besides the financial benefits, composting allows saving natural resources by transforming biowaste into a product, reducing harmful impact of chemical fertilizers to soil. This article paves the way to further research and should encourage more experiences in this field, transforming waste into ready available compost.