Sustainability of using composting and vermicomposting technologies for organic solid waste biotransformation: recent overview, greenhouse gases emissions and economic analysis

Organic solid waste poses a serious threat to the environment as the world struggles to keep up with its rapid generation. Biological waste treatment technologies such as composting and vermicomposting are widely regarded as a clean and sustainable method to manage organic waste. The focus of this review is to evaluate the feasibility of composting and vermicomposting as a means to recover nutrients from the organic waste and returning them to the environment. The environmental impact and economic potential of these processes are also discussed. This review shows that composting and vermicomposting are capable of degrading various types of organic waste, thus enabling them to be adopted widely. The present review also reveals that greenhouse gases are emitted during composting and vermicomposting processes. However, introductions of intermittent aeration, bulking agents and earthworm abundance may reduce the greenhouse gases emissions. Economic assessments of composting and vermicomposting technologies show that these technologies are generally viable except in some cases. The differences are due to the wide range in market value for organic fertilizer and differences in cost for the type of composing or vermicomposting system which could affect its economic feasibility. However, if organic fertilizer value increases and carbon offsets are available for nutrient recycling, it will affect the economic feasibility in a positive way. (c) 2015 Elsevier Ltd. All rights reserved.