Financial sustainability of modern composting: the economically optimal scale for municipal waste composting plant in developing Asia

There is a widespread interest in convertingorganic waste into compost fertilizer to extend the life oflandfills, create economic and environmental benefits, andultimately reduce the pressure on local governments inmanaging the ever-increasing complexity of municipalsolid waste. However, composting is still seldom consideredas a strategic element. There is also very little evidenceavailable of its economic feasibility. This study,therefore, aims to analyze key factors that influence theeconomic feasibility of municipal composting plant andidentify a range of plant capacity or scale where a compostingproject could have higher opportunity to be financiallysustainable. A cost–benefit analysis (CBA) wascarried out using the data gathered from five compostingplants in Asia, including Surabaya, Bali and Bekasi inIndonesia, Beijing in China, and Matale in Sri Lanka. Theresults identified that the medium-scale and lower largescalecomposting plants have an optimal opportunity forbeing financially feasible as compared with the smaller andlarger capacity plants. The study also identified that theeconomic viability of the composting plants depends on thenumber of factors, such as selection of suitable processingmethods, technologies, scale, quality of product and marketingstrategies. The advantages of the medium and lowerlarge-scale composting plants are (1) waste input andproduct quality are easier to control than larger scalecompost plants, and (2) there are extra income opportunitiessuch as tipping fees and carbon credits that are limitedin the case of small-scale composting plants. The scale ofcomposting plant is one of the key factors to be consideredat the initial stage of planning composting plants.