COMPOSTING OF MUNICIPAL SOLID WASTE: AN EMPIRICAL ANALYSIS OF EXISTING PLANTS

Thousands of tonnes of Municipal Solid Waste (MSW) are produced every day, and consignment to landfill represents the most common disposal choice. However, sanitary problems and the increasing demand for dedicated spaces have directed the efforts of researchers and practitioners towards the study of alternative approaches to waste management. Composting is one possible way to treat the organic portion of MSW, and the efficient design and management of composting plants ensure that they are economically sustainable. Analyzing established or pioneering solutions allows guidelines to be drawn up for the design of new plants and/or the management of existing ones. In this paper, a set of engineering indices for the technical and economic analysis of composting plants is first presented and then applied to data collected from 10 existing plants, divided into two subgroups: plants mainly composting the organic fraction of household solid waste, with reduced levels of the organic fraction of agro-industrial waste, green waste and sludge (named Group A), and plants only composting green waste (named Group B). For Group A plants, more complex technological solutions are required, given the need to manage larger portions of untreated waste and leachate, along with odor problems. This means that the need for space (particularly covered space), facilities, operators, and initial investment is greater and annual operating costs are higher. However, Group A plants can also charge more for processing waste.