STATUS OF WTE IN EUROPE (article from Waste Management World, International Solid Wastes Association, May-June 2002)

Transcription

1 STATUS OF WTE IN EUROPE (article from Waste Management World, International Solid Wastes Association, May-June 2002) Håkan Rylander and Jørgen Haukohl New figures from the ISWA Working Group on the Thermal Treatment of Waste give an insight into the role played by waste-to-energy - or incineration - plant in Europe. As EU legislation on landfilling will make increasing demands on the minimization of waste, the number of incineration plants across the continent looks set to increase. This article presents ISWA's figures, and assesses the current status of waste-to-energy in Europe. Everyone involved in the protection and appropriate use of raw materials, natural resources and the environment, as well as those involved in the day-to-day operation of solid waste management, aims to reach what could be called the 'Eco Cycle Society'. In this society, the use of resources will be minimized, keeping them within a closed cycle. This entails an integrated system of solid waste management, employing a combination of different methods to minimize the use of resources, and then reusing, recycling or recovering as much as possible of what is used, to create that closed cycle. There should not be any conflict between the different methods used; on the contrary, they should be complementary.?? Domestic and industrial recovery of material needs to involve the co-operation of those responsible for collection in the recovery and recycling of different materials and products.?? There is a need for increased utilization of the material and energy resources represented by industrial waste. Conservation of resources should mainly take place within industries themselves, by using low-waste technology, and internal recovery of residues and waste.?? Thermal treatment of waste should be undertaken, with energy recovery.?? The easily biodegradable part of organic waste should be utilized in the production of biogas and compost.?? Landfilling, which will still be needed to supplement other methods of waste management, should only be used for non-recyclable materials and for residues from other waste treatment. Experience gathered of the different systems used for solid waste management from around the world clearly shows the need for integrated waste systems. It also demonstrates that, as recovery, recycling and composting of materials - as well as energy recovery from thermal treatment - increase, the instances of landfilling decrease. Although the amount of waste has not necessarily decreased, it is now handled in other waste flows. Waste incineration - background and current trends Waste incineration is a well proven and established method for treating municipal solid waste (MSW) in Europe, with the first plant built during the 1890s. Waste incineration was originally used for reasons of hygiene, not least to solve the enormous problems presented by cholera in the densely populated cities of Europe. By the 1900s, it was also beginning to be seen as a method for reducing the increasing volumes of waste being generated. It is worth noting that, at that time, incineration was not associated with any form of recovery. In a society that considered material flows as linear - raw materials being provided from virgin materials and waste dumped without any recycling - the need for such recovery may not have been perceived. However, in a contemporary society informed by ideas of

2 sustainable development, and with the aim of a 'cyclic flow' from resource to waste back to resource, recovery is an essential concept. The only objective for waste incineration relevant to the 'Eco Cycle Society', therefore, is energy recovery. Volume reduction is no longer an objective, although it is still an important parameter when assessing environmental impact. Furthermore, incineration is only justified when it can be proven to be at least as favourable as other recycling or recovery options. In many countries, permission to build a new waste incineration plant will not be granted unless the energy produced will be recovered. Besides, the operation costs in a modern plant, with advanced flue gas cleaning and a strict handling of residues, make the income for energy recovery essential. Statistics The ISWA Working Group on Thermal Treatment of Waste has recently published the fourth (January 2002) edition of statistics on its member countries. The report includes waste incineration in the member countries - namely Austria, Belgium, Denmark, France, Germany, Great Britain, Hungary, Italy, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the USA. The report presents information on the incineration plants by year for 2000 and 2001, and also includes operational data from It has been prepared on the basis of answers to a questionnaire distributed to incineration plants in the member countries which covered normal incineration plants with a capacity of more than 15 tonnes/day or 10,000 tonnes/year (this excludes special plants for hazardous waste, sludge, agricultural and hospital waste). National data collected Data have been collected from each member country by the Working Group's national representatives, and include information on each plant such as owner, year of establishment, capacity, calorific value and type of furnace, boiler and flue gas cleaning system. The data also cover plant information such as flue gas temperature, types of waste incinerated and steam temperature and pressure. The operating data for includes information on hours of operation, fuels, energy recovery and handling and amount of residues. Comparison of national data The first section of the report compares the data on waste incineration in 14 of the member countries (excluding the USA), in terms of number of plants and furnaces, national capacity, types of furnace and flue gas cleaning systems, and the amounts of waste incinerated and energy recovered. Complete national data are provided for Denmark, France, Germany, Hungary, the Netherlands, Portugal, Spain, Sweden and Switzerland. Amounts of waste incinerated The total amount of waste incinerated in the 14 countries in 1999 amounts to approximately 41 million tonnes, with Germany the country incinerating the most waste, at about 13 million tonnes (see Figure 1).The statistics in this field do not, however, entirely reflect the present situation, as they exclude waste treated at 15 out of 18 Belgian plants, 11 out of 120 French plants, 14 out of 31 Swiss plants and 4 out of 62 Italian plants. FIGURE 1. Amounts of waste treated, 1999

3 In terms of waste incinerated per capita in 1999, Denmark and the Netherlands rank highest, as illustrated in Figure 2. To meet the EU Directive 1999/31/EF, the amount of waste that is landfilled must be minimized. Subsequently there will be an increase in the quantity incinerated in the future, and energy recovered. In many countries, incineration capacity is lagging considerably behind the capacity necessary for this aim to be met, and will remain so for quite some time. FIGURE 2. Waste amounts treated per capita, 1999 National capacity The capacity of the plants varies between 1.2 and 60 tonnes/hour. The number of incineration plants in each member state does not therefore reflect the actual waste incineration capacity.

4 The total capacity in the 14 member countries in is shown in Figure 3a; Germany has the largest capacity. In terms of capacity per capita, Denmark ranks the highest, followed by the Netherlands and Hungary, as illustrated in Figure 3b. FIGURE 3a. Waste-to-energy - national capacity Several countries have built or are currently building new plants, and upgrading existing ones, to meet both the new EU Directive 2000/76/EF on waste incineration and the requirements for environmentally acceptable treatment of the increasing amounts of combustible waste generated. For example, during the 1990s, the Netherlands completed the construction of ten very modern plants of high capacity, the UK constructed several new plants, and a new plant was put into operation in Basel in Switzerland. Furthermore, a number of new plants have been constructed or are under construction in Denmark, Norway and Sweden, both to increase incineration capacity and to replace old plants. In the Scandinavian countries, many plants are also being converted to combined heat and power generation. FIGURE 3b. Waste-to-energy - capacity per capita

5 In most European countries, there are currently plans to build new plants and increase incineration capacity, even in those countries where there are no existing waste-to-energy plants, such as Ireland. Due to the new EU Directive on waste incineration, however, a number of small plants will be closed down, as they cannot meet the directive on emission limit values at a reasonable cost. This waste-to-energy plant at Malmö, Sweden will soon be joined by a new facility Emission guidelines and flue gas cleaning systems Almost every country has its own legislation concerning emissions from MSW incineration. However, all member countries of the European Union have to comply with the same EU Directives as a minimum. To achieve national and EU standards, advanced flue gas cleaning systems have to be installed; strict directives on emissions can be complied with by using state-of-the-art cleaning techniques, although this will still require considerable effort. In principle, newly designed flue gas cleaning systems often use the following sequence of equipment:

6 ?? electrostatic precipitators?? multi-stage wet scrubbers with wastewater evaporation?? fabric filters or wet electro-venturies with lime injection/active cokes?? SCR-DeNOx or SNCR-DeNOx. Today, almost all incineration plants have some kind of flue gas cleaning system, and several have more than one (for instance, wet scrubbing combined with an electrostatic precipitator). Figure 4 illustrates the most common flue gas cleaning systems a nd their use as a percentage of the furnaces in 13 of the countries. Energy recovery In almost every country with waste incineration plants, there is some kind of energy recovery. In general, there are two important uses for the energy recovered. Scandinavian countries use a high percentage of the recovered energy to produce hot water for district heating; the other countries, meanwhile, mainly produce steam for electricity production, mostly without using the remaining energy, which simply goes to waste. However, outside Scandinavia, there are moves towards more effective use of produced heat, as well as a significant tendency in the Scandinavian countries for more and more combined heat and electricity production. FIGURE 4. Flue gas cleaning systems by percentage,

7 Energy recovery from waste incineration is becoming more common; the total energy recovered in 1999, as electricity and heat, is shown in Figure 5. The figure shows that energy recovery is particularly high in countries where the heat can be used for district heating systems - Denmark, France, Germany and Sweden. FIGURE 5. Energy production from waste incineration, 1999

8 In many countries there have been significant increases in the recovery of the energy produced and decreases in emissions, while at the same time, the amount of waste incinerated has not increased proportionally. Residues from waste-to-energy In general, the only part of the residues that can currently be reused is the bottom ash (slag). Before reuse, this can be crushed and/or sieved, with iron scrap being removed and in many cases recycled. Dependent on the quality of the bottom ash, it can be recycled and used in construction work, for instance. Several processes are under development which will improve the bottom ash quality, to ensure it can be disposed of when the regulations are toughened. The bottom ash that is not reused is landfilled; however, because of the large amounts of bottom ash produced in waste incineration, there is pressure to reuse as much of it as possible. In some countries, the 'gravel' fraction of the bottom ash is used in the construction of roads, car parks and so on. Figure 6 shows the percentage of the bottom ash recycled and deposited in It should be noted that not all incineration plants are included in the data. There is a very limited reuse of residues from the different flue gas cleaning systems but most of it is landfilled in a secure way - stacked in big bags, stabilized with binders or in some other way safely landfilled. As emissions to the air are now very well controlled and cleaning technology is very advanced, research and development is increasingly focusing on the safe handling and better use of residues. The ISWA Working Group on the Thermal Treatment of Waste in particular is concentrating on this topic at the moment, examining it in position papers, with a possible view to making some recommendations.

9 Development and new technology Most development within waste-to-energy takes place within existing technologies:?? improved incineration conditions in the furnaces, with more effective incineration of the organic content in waste and in flue gases?? improved energy recovery, with measures to minimize corrosion problems?? improvements in flue gas cleaning equipment. To some extent, new technology is being introduced in the field of flue gas cleaning, but even here, most development takes place within existing systems. Incineration on grates is still the prevalent technology, with several designs of fluidized bed system as the alternative. Most waste-to-energy processes take place in large units and in large plants, though interesting installations with grates in small units and small plants have been introduced and operated in recent years. This small-scale technology can be of considerable interest to smaller cities, municipalities and different industries, if it is shown to work satisfactorily in the long term. For some time, efforts have also been made to develop and introduce gasification and pyrolysis as methods for the thermal treatment of waste. So far, there has been very little success, and a number of failed attempts. For the time being, results - and experience - from the full-scale Thermoselect plant in Karlsruhe are being followed closely by all those interested in waste treatment and waste-to-energy. However, there is at present no clear indication that the full-scale technology works in a entirely satisfactory way. At the small scale, gasification technology has been introduced at some plants in Scandinavia, though once again, the longterm results and experiences will be closely watched, before any certain conclusions can be drawn. FIGURE 6. Depositing/recycling of bottom ash by percentage, 1999

10 Conclusion Waste-to-energy is an established method for waste treatment and energy recovery that functions well. Due to far-reaching restrictions on the landfilling of municipal waste in many countries, there will be an increased need for waste incineration with energy recovery to complement recycling and biological treatment of waste. New plants will be equipped to use the produced energy for heating purposes as well as for electricity generation. Strict emission directives and guidelines will result in the installation of highly advanced flue gas cleaning systems. It is to be reiterated that the only objective for waste incineration that is relevant to the 'Eco Cycle Society' is that of energy recovery. Volume reduction is no more an objective, even if it is an important parameter when assessing environmental impact. It is also very important to remember that incineration is only justified when the method is at least as favourable as the options for recycling or recovery. The new Malmö waste-to-energy plant, Sweden, will begin operation next year, complementing the original facility

11 The ISWA Working Group's report can be obtained at the price of DKK 550 from the following address: ISWA General Secretariat Overgaden Oven Vandet 48E DK-1415 Copenhagen K Denmark Tel: web: HÅKAN RYLANDER is Managing Director of SYSAV, The Southwest Scania Solid Waste Company, Sweden. He is also Chairman of the ISWA Working Group on the Thermal Treatment of Waste, and was President of ISWA from hakan.rylander@sysav.se JØRGEN HAUKOHL works for Rambøll, Denmark, and is Vice Chairman of the ISWA Working Group on Thermal Treatment of Waste. Fax: jh@ramboll.dk James & James Home Page Waste Management World Home Page Back to top of page