Solid waste systems assessment

Introduction: Wastes are defined in the Waste Framework Directive (European Parliament and Council of the European Union, 2008) as ‘any substance or object which the holder discards or intends or is required to discard’. Over the last two to three decades, waste management in the industrialised world has gradually shifted from providing safe disposal of unwanted materials, often by entombing the waste in a sophisticated, engineered landfill, to recovering materials and value from that which is no longer needed through reuse, recycling, composting and energy recovery. In Britain, this shift has resulted in a 71% reduction in the amount of biodegradable municipal waste (BMW) going to landfill since 1995. Recycling and composting have increased from almost nothing in 1995 to nearly 45% of municipal waste treatment today and energy from wastes accounts for about a third of renewable energy generated (Defra, 2015a). This has required significant investment in infrastructure as well as sustained efforts to change the attitude of industry and consumers. Recent publications on resource security (Defra, 2012), resource efficiency (European Commission, 2011) and sustainable materials management (OECD, 2012) show that there is a move away from the linear view of resource management (extraction, manufacture, use, final disposal) towards a more circular view in which waste management becomes primarily a resource recovery operation and final disposal is necessary only for those materials from which further value can no longer be economically or technically extracted. Material and value are recovered from wastes through recycling and composting (42%) and energy recovery (22%) with the remainder being landfilled (34%). (Figures are from Defra for 2012/2013 and are for local authority collected waste (LACW) in England.) Recycling accounts for most of this recovery and the rates for the most commonly collected materials (glass, steel, aluminium, dense plastics (e.g. plastic bottles) and paper, card and cardboard) are shown in Table 8.1. Garden wastes are recovered for composting and food or mixed food and garden wastes for in-vessel composting (IVC) or anaerobic digestion (AD). Other materials (e.g. tetrapaks and plastic film) are recovered more rarely. Energy is generally recovered by incineration from mixed wastes, from mixed wastes processed to produce fuels (solid recovered fuel (SRF) or refuse derived fuel (RDF)) for co-combustion or through the AD of biodegradable wastes (usually food waste or mixed food and green waste).