Resource Recovery from Organic Fraction of Municipal Solid Waste in Sri Lanka – Current Status and Future Prospects

Abstract

Owing to rapid population growth accompanied by urbanization and industrialization, waste management is an essential aspect of today s world. During 2013, total municipal solid waste generation in Sri Lanka was recorded as 10,768 tons per day, while total municipal solid waste collected was only 3,458 tons per day. Meantime, the organic fraction of municipal solid waste (OFMSW) produced in 2012 was 1,301.5 tons per day. The most widely practiced waste disposal method in Sri Lanka is currently open dumping, which is not an ecofriendly approach. Biowaste, which accounts for about 59% of MSW collected in Sri Lanka, consists of 65 percent of moisture, and valuable resources such as energy, nutrients, and minerals can be readily recovered. Resource recovery, which is linked to the circular economy, is a sophisticated technique of biowaste management. However, resource recovery principles for the local communities in Sri Lanka are fairly novel. The ultimate outcome of this study is to lay the foundation for the development of an autonomous integrated circular system integrated with the existing waste management framework in Sri Lanka, and thus allowing to circulate the vital resources needed to sustain human life in the form of energy, food, and water. Types of resources, which can be extracted from OFMSW are nutrients such as nitrogen and phosphorous, energy, and water from moisture content. Energy can be harnessed as biogas via the degradation of organic compounds in anaerobic reactors, whereas nutrients can be harnessed by converting anaerobic sludge into inorganic fertilizers. The proposed integrated standalone circular system should be able to produce energy via combined heat and power plant and produce struvite via fertilizer production plant. Based on currently available data from 2012, potential electricity generation is 10.31 W per kg of OFMSW, and minimum struvite generation potential is 3.839 g per kg of OFMSW. Excluding the operation and maintenance expenditure and depreciation cost, forecasted revenue from electricity generation and struvite production are respectively is 21,155,926 USD per annum and 455,926.84 USD per annum. Therefore, resource recovery is a socio-economically and environmentally viable waste management practice in the Sri Lankan context.