The incineration of urban waste has been practiced for without serious regard to emissions or for recoverable energy. In the last century, efforts began to recover the energy and, more recently, work has been undertaken to recover useful materials in the bottom ash, and even to use it as a construction aggregate. Waste to energy may even help achieve more sustainable urban waste management. In Europe, legislation (including landfill taxes) will gradually phase out landfilling, and waste to energy is seen as an attractive alternative there.
Yet fears persist of the technology in Canada where new waste-to-energy proposals are nevertheless emerging.
There is an obvious historical reason for the negative reaction to incineration. Many early low-temperature incinerators released toxic chemicals in the flue gases, including dioxins (a byproduct of incomplete combustion). Society found this unacceptable and increasingly strict emission regulations resulted in the closure of many incinerators. Until this problem was solved with appropriate flue gas treatment, incineration had no legitimate future. But technical innovation has made modern waste-to-energy plants into very different creatures, as a look at a European example illustrates. Let’s consider the waste-to-energy facility of the City of Amsterdam, the so-called Afval Energie Bedrijf (AEB). In operation since 1993, it has shown what can be achieved with modern technology and motivated management. Similar examples can be found in Austria, Denmark, Germany, Sweden, or Switzerland.
What AEB has demonstrated is that:
* Occupying less than 10 hectares of ground, the AEB plant has treated 850,000 tonnes of urban waste and 25.000 tonnes of sewage sludge annually. At the same time, it has produced 530,000 MWh of electricity and 150,000 GJ of heat.
When the Waste-Fired Power Plant (WFPP) is completed in 2007, AEB will treat 1.4 million tonnes of waste and 100,000 tonnes of sewage sludge, while producing 1.0 million MWh of electricity and 250.000 GJ of heat.
* Relatively pollution-free waste to energy is technically and economically feasible.
Equipped with state-of-the art flue-gas cleaning technologies, AEB operates consistently 80 per cent below strict Dutch and European regulatory emission limits. This fact is fundamental to the success of the operation in terms of technical performance and community relations. It is entirely reasonable that our societies no longer tolerate a polluting or obnoxious waste treatment operation.
To obtain pollution-free waste to energy requires a sizable investment in flue-gas cleaning. However, AEB demonstrates that with high efficiency of energy recovery (in terms of electricity and heat), the investment is viable.
* In addition to replacing fossil fuels, the high degree of energy efficiency results in lower costs to the consumer and taxpayer.
AEB charges n65 per tonne of waste received. This compares favourably with landfill and other waste treatment fees across Europe. AEB sells electricity to the grid and hot water for district heating at market prices.
The potential energy that can be recovered from incineration of urban waste is enormous.
In its current operation with its first waste-to-energy plant, Amsterdam is producing electricity and heat equivalent to 66,000 barrels of oil per month. When the WFPP begins operations in 2007, it will replace fossil fuels by the equivalent of 111,000 barrels of oil per month.
These results can be achieved with technology available today. Further improvements in energy efficiency should be possible, however, and deserves continued research and development.
* Waste to energy operates in parallel with maximum prior recycling, and in addition, valuable materials can be recovered (recycled) from bottom ash.
Household separation of glass, metals, certain plastics, paper, cartons and green waste from urban waste and recycling (to the maximum that is industrially feasible) is a key feature of a modern waste management strategy. The organization of recycling by local authorities needs not be affected by subsequent waste to energy. Recycling rates have increased in the Netherlands and other European countries that are the more advanced in developing waste to energy. In addition, it’s becoming apparent that valuable materials can be recovered and recycled from bottom ash.
About 23 per cent (by weight) of the incoming waste by weight remains as bottom ash. In the past, it was used directly for road construction or was landfilled, but bottom ash has now been shown to be a rich source of many useful materials that can be recovered. A continuing development program carried out jointly by AEB and Delft’s Technical University is showing that non-ferrous (and precious!) metals can be recovered from bottom ash, and that it can be treated to produce high quality construction materials. This program is suggesting that near-100 per cent recovery of combustible urban waste may be achievable.
* Public opposition to waste to energy can be overcome.
As a result of a systematic and effective campaign of public communication and dialogue conducted in an open and transparent manner, AEB’s operations are accepted and supported by a broad spectrum of Dutch society. This is a significant achievement in a country that has a population with a high level of environmental sensitivity and concern. It should be noted that in addition to the Netherlands, other European countries where waste to energy is now a major component of the waste management strategy — Denmark, Germany, Sweden — all have strong environmental movements.
* Regulatory approval can be straightforward.
Although permitting procedures differ from country to country, waste-to-energy facilities with a demonstrated minimal environmental impact, and public support, should be able to obtain regulatory approval within predictable timing. In Amsterdam, the WFPP project completed the regulatory permit procedure without a single opponent.
Our purpose in publicizing the example of Amsterdam’s AEB experience is to begin to dispel the many misconceptions about waste to energy that have developed in the public mind. Information about the AEB operation, as well as the facility itself, are available.
Note: A presentation about waste to energy and the Amsterdam plant will be made at the 2006 Canadian Waste & Recycling Expo in Toronto, Ontario in November.
Eveline Jonkhoff is manager, Public Affairs and Corporate Communication, City of Amsterdam Waste and Energy Company. Thomas McCarthy is Director and Senior Consultant of Croft Stainshield Ltd.., Dublin, Ireland