Technical Report

Source separation of MSW

An overview of the source separation and separate collection of the digestible fraction of household waste, and of other similar wastes from municipalities, aimed to be used as feedstock for anaerobic digestion in biogas plants

November 2013

This report examines the source separation of the digestible fraction of household waste and of other similar wastes from municipalities, prior to anaerobic digestion (AD). This is a topic of increasing worldwide relevance, as nations seek sustainability in the management of their organic wastes.

Global quantities of wastes are continually increasing, with the growth in the world population and increasing urbanisation. Waste management faces serious challenges around the world, especially in urban areas, moving away from disposal to waste prevention, resource recovery and recycling. Considerable efforts are being made to limit the overall production and the harmfulness of waste, and to limit the negative impact of waste on the environment and on human and animal health, as well as to mitigate the financial costs of waste management. Separation of wastes at source, including source separation and anaerobic digestion (AD) of the digestible waste fraction from households, is an integral part of such efforts, enabling recovery of value from the separated waste fractions through the production of cleaner, improved quality materials for energy recovery and recycling. Source separation helps divert organic wastes from landfill and from incineration, thus reducing the overall emissions of greenhouse gases and the negative environmental and health effects related to these waste disposal methods. Increased public awareness and active commitment and participation of citizens in local collection schemes are required.

The report is intended to provide municipalities and decision makers with guidance on the source separation of the digestible waste fraction from households and commercial origins, with the aim of obtaining a clean, high quality material, suitable for used as feedstock for anaerobic digestion in a biogas plant. The report contains documented information, which, when complemented by analysis of the local waste situation, should assist municipalities to design and implement sustainable policies for solid waste management.

The digestible household waste, as referred to in this report, includes not only food waste and green garden waste from households, but also similar digestible wastes from institutions, digestible municipal park and garden trimmings, vegetable residues and discarded food from markets and catering businesses, outdated food from supermarkets etc. The term “digestible wastes” used in the report defines organic waste materials, which can be easily decomposed by the anaerobic digestion process. The term “similar wastes” refers to municipal solid wastes, similar in nature and composition to household wastes, produced by commercial, industrial and institutional organisations.

The report provides an overview of the global waste situation and highlights the key incentives behind source separation of household waste for AD treatment in biogas plants. It describes some commonly used source separation and collection schemes for food waste from households and the process of their implementation, mainly based on experiences from United Kingdom and Sweden, countries that have gained experience and positive results in this area. To disseminate best practice and facilitate learning, the report also describes examples of successful municipal source separation schemes for digestible household waste from Sweden, United Kingdom and South Korea.

Much of the information presented is based on the literature sources listed in the references. It is worth noting that it was difficult to find specific consolidated data on the production and treatment of digestible wastes either nationally or globally. The main part of the existing literature refers to the larger categories of “organic wastes”, and of “biowastes”, in which digestible wastes are included, but are combined with other wastes. (See also ‘Glossary, terms, abbreviations’).