Issue No.01 COMBUSTION WITH ENERGY RECOVERY KEY POINTS: Combustion with energy recovery is an integral part of solid waste management strategies in many countries (including nearly all OECD countries), but not Australia. Internationally, its importance is growing, notwithstanding the significant capital investment required. Recent national enquiries in the United Kingdom and the Netherlands have supported the increased use of combustion in solid waste management policies. Greater use of energy recovery will reduce the pressure on landfill and by reducing the use of fossil fuels, will help alleviate problems associated with the Greenhouse effect. Emission control standards have increased substantially over the last decade and are now very strict, consistent with the highest health policy requirements. In Australia, greater use of combustion with energy recovery would contribute to more effective national waste management and energy conservation policies. Combustion can be used to reduce the original volume of municipal solid waste (MSW) by 85 - 95 percent. Combustion is not only a method of treatment and disposal for wastes but can also be used to recover a substantial proportion of the energy contained in the waste. This energy can be used to provide heat and produce electricity. Technical Details Combustion is the thermal processing of solid waste by chemical oxidation with air. End products include hot combustion gases (nitrogen, carbon dioxide and water vapour) and non-combustible residue (ash). Energy can be recovered by heat exchange from the hot combustion gases and used mainly for the generation of electricity, but also for steam and hot water. Solid waste combustion systems can be designed to operate with two types of solid waste fuel: commingled solid waste (mass-fired or mass-burn) and processed solid waste or refuse-derived fuel (RDF-fired). Mass-burn combustion systems are the predominant type. As source separation develops and the waste derived fuels become more homogeneous and of higher quality, other combustors (e.g. fluidised beds) will develop. In a mass-burn combustion system, minimal processing is given to solid waste before it is fed into the combustor. Typical calorific values of MSW values in western Europe are around 10.8 megajoules per kilogram, while in parts of Asia the figure is as low as 5.8 MJ/kg due to a higher food scrap content. The western European figure means that 2.6 tonnes of MSW has the same energy content as 1 tonne of coal. However, unlike coal, MSW is a variable fuel, affected by season and region. Combustion of MSW is a capital-intensive process, with net costs highly sensitive to the scale of operation and the revenues received for the energy recovered. International Experience Combustion with energy recovery is widely used throughout the world: • In western Europe, combustion is the second most common form of waste disposal. Denmark and Sweden combust 65% and 55% respectively of MSW. France combusts 42% (including 100% for Paris), the Netherlands 40% and Germany 30% of MSW. Both the draft EC Directive on Packaging and the French Packaging Decree (but not yet the German Packaging Ordinance) permit energy recovery of packaging waste. The EC imposes the highest level of environmental and health regulations on the operation of combustion facilities. • In Singapore, MSW is collected daily, with 85% combusted (with energy recovery) in three modern combustors equipped with gas cleaning equipment. • In Japan there are about 2000 combustors for MSW. Over 100 (28% of installed capacity) recover energy and generate electricity. • Taiwan is committed to build 23 combustors; two are now operating. • Seoul (South Korea) is committed to combust all its MSW by the year 2000. • The recent Report of the United Kingdom Royal Commission on Environmental Pollution (the Houghton Report) has recommended increased use of combustion to manage Britain's waste. Australian Reluctance In Australia, by contrast, less than 1% of MSW is combusted. This is due to a combination of factors, particularly the public perception of combustors as polluting, leading to the NIMBY (Not In My Back Yard) syndrome and a political reluctance to grasp the issue. Environmental Impact The emission requirements for MSW combustors have increased rapidly in recent years. These requirements are very strict for all compounds, although public attention has focussed on dioxins. These are a family of compounds emitted during combustion of MSW as well as other burning processes such as forest fires and open fires in the home. Dioxin emissions can and should be brought down to concentrations as low as 0.1 - 2.0 nanograms per cubic metre by proper combustion control methods. The lower value is at the outer limit of the most sophisticated detection techniques. In context, 0.1 nanograms per cubic metre means that 1 gram of dioxins is emitted in 10 billion cubic metres of flue gases. Making valid comparisons between alternative methods of treating MSW is extremely difficult. Every waste treatment option has the potential to pollute. Air pollution from landfills has not been as extensively addressed (nor can it be as effectively measured) as that from waste combustion, but it undoubtedly exists. There are also the associated problems of litter, rodents and odours from many landfill sites. The use of MSW as an energy source results in the minimisation of the uncontrolled emission of gas from landfilled mixed wastes. Various techniques are in place for the reuse of the ash residue from modern combustion plants including its use as brick pavers and in road aggregate and surfacing operations. THE PACKAGING COUNCIL OF AUSTRALIA'S POSITION Combustion with energy recovery has a role to play in the management of Australia's MSW. Combustion can meet very strict environmental standards. As we seek to conserve energy and restrict costs, it makes no sense to landfill MSW when technology exists to recover the energy it contains. Since MSW typically consists of over 50% of renewable resources, it can be described as a bio-fuel. Given the increasing quantities of MSW which are being combusted with energy recovery around the world, it is evident that MSW will become an important bio-fuel of the 21st century. A wider use of combustion to recover energy from MSW would not lessen the responsibility of Australian companies to adopt other environmentally responsible policies such as source reduction, re-use and forms of material recycling. Read other Issues Papers: No.02 - "Life Cycle Analysis" No.03 - "Managing Packaging Waste in Europe - Lessons for Australia" No.04 - "Waste Management" No.05 - "Litter" No.06 - "Mandatory Deposits" No.07 - "Excessive Packaging" No.08 - "Recycling" No.09 - "Australian Packaging - How Competitive?" No.10 - "The Packaging Council of Australia" No.11 - "Mandatory Minimum Recycled Content" No.12 - "Eco-Labelling" No.13 - "Packaging - Ten Trends for The Next Ten Years" No.14 - "Packaging - It's Essential Role" No.15 - "The Internet - What it Means for Australian Packaging" No.16 - "Single, Active, Post-Materialistic, and Grey?" No.17 - "Digitisation in Printing - Implications for Packaging" No.18 - "Australian Packaging: Issues and Trends"