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Environmental impact
of municipal waste
incineration plant
Martyna Nowakmgr eng. Martyna Nowak: Institute for Chemical Processing of Coal, ul. Zamkowa 1, 41-803 Zabrze; e-mail: mnowak@ichpw.pl
Introduction
Waste generation is inherently connected to every human activity. According to the Act of 14 Decem-ber 2012 on waste (Journal of Laws of 2013, item 21, as amended), the sources of municipal waste are house-holds and other producers generating waste with simi-lar properties as the waste of households. According to the statistical data from the Central Statistical Office, in 2012 over 12 million tons of municipal waste was gener-ated in Poland, which corresponds to an average of 314 kg per capita annually. However, this is still less than in western European countries (over 400 kg per capita annually according to Eurostat). The largest amount
received: 6.10.2014; accepted: 23.02.2015; published: 27.03.2015
Summary:
Building an incineration plant is a project of a huge so-cial undertaking. Neither environmental organizations nor the residents near the locations of such installations are likely to express support for such construction. Some of the main issues raising emotions in society are: emis-sions of harmful substances into the air, large investment costs and problems with managing residues. This paper presents the advantages and disadvantages of building municipal waste incineration plants, current waste ma-nagement, and also the results of an LCA analysis on the environmental impact of chosen waste management stra-tegies.
Key words: incineration plant, waste management, LCA
of municipal waste was generated in the Mazowieckie Voivodeship – almost 2 million tons, which is 363 kg per capita, while in the Świętokrzyskie Voivodeship, the amount of produced waste was the smallest – 229 000 tons, which is 180 kg per capita (Fig. 1).
Collected municipal waste is processed in recovery or disposal processes. According to the definition in the Act on waste, recovery is a process in which the main purpose is to transform the waste into materials which can be reused. We also distinguish energy recovery, or thermal waste processing (usually in incineration plants), to recover energy. Disposal is not a recovery process, even if the secondary effect is material or en-ergy recovery. The disposal process is e.g. landfilling or
Fig. 1. Amount of municipal waste generated in each voivodeship in 2012 in thousands of tons
Source: GUS (Polish Main Statistical Office) 2013.
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thermal processing without energy recovery. According to the waste hierarchy, also located in the Act on waste, prevention is the most desirable solution (Fig. 2).
Prevention must take place during the design of a specific object or during the production process. The amounts of used resources, materials, energy, the amount of produced waste and also the method of prod-uct disposal after the operation should be estimated. All these actions led to the development of input-output analysis, which is called the life cycle assessment (LCA) since 1990 (Grzesik 2006). More information about the LCA is in the section on the environmental impact of waste incineration plants.
Figure 3 shows the treatment of municipal waste in Poland in 2012. The largest share – 88% of waste – was disposed of in landfills. The rest was recovered – 11% at composting plants (recycling or organic substances recovery) and only 1% in waste incineration plants (GUS 2013). Presently in Poland, there is only one operational municipal waste incineration plant, in Warsaw, which explains the low amount of incinerated wastes. Under the Operational Programme “Infrastructure and Environ-ment”, six incineration plants will be built – in Białystok, Konin, Poznań, Kraków, Bydgoszcz, and Szczecin.
In accordance with the definition in the Act on waste, waste treatment with or without energy recovery takes place in a waste incineration plant. Such a plant consists of:
• devices and installations used for performing the thermal treatment process,
• a system to clean exhaust gases and emit them into the air,
• installations for the receipt, primary treatment and storage of waste supplied to the thermal process,
• installations for the receipt, primary treatment and storage of waste generated during the thermal pro-cess,
• controlling and monitoring devices.
In the following section, the technological diagram of an exemplary municipal waste incineration plant (Fig. 4) as well as the operation of such an installation are presented.
Incineration plant
According to the Act on waste, the thermal treat-ment process is a waste combustion process or other process, including pyrolysis, gasification or plasma
pro-Fig. 2. Waste hierarchy
Journal of Laws of 2013, item 21, amended.
Fig. 3. Treatment of municipal waste in Poland in 2012
Source: GUS, 2013. Incineration plants 1% Composting plants 11% Landfills 88%
cesses, if the substances produced during these process-es are subsequently combusted.
Figure 4 presents a diagram of an exemplary mu-nicipal waste incineration plant that is shown in the Environmental Impact Report for the thermal waste treatment plant in Kraków. Municipal waste collected from producers is unloaded in the waste acceptance hall, where it is pretreated. Waste is loading into the boiler through a proper dosing system. Thermal treat-ment lines are equipped with secondary air fans, ena-bling the incineration to perform properly. The grate is
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equipped with a residues (slag, bottom ash) and met-als receiving system. Under the boiler and economizer (heat exchanger), hoppers are placed to which the ash is directed. Residues from the incineration process are recovered or disposed, with the disposal of heavy metal fractions. Exhaust gases produced in the process are
di-rected to a heat recovery steam generator (where steam is generated by the energy recovered from the exhaust gases), then to an exhaust gases cleaning installation, a fan and finally the stack, through which the gases are emitted into the atmosphere. Exhaust gases must meet emission limit standards, presented in the Regulation of
the Minister of the Environment of 4 November 2014 on emission standards for various installations, combus-tion sources and waste incineracombus-tion or co-incineracombus-tion devices (Journal of Laws of 2014, item 1546) (table 1). Water feeding the boiler is supplied by the municipal network after treatment. The steam produced in the
Fig. 4. Diagram of an incineration plant
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boiler is used for the production of heat and electric-ity. Steam from the boiler goes through a turbine, and then partly through steam extraction (used for heat-ing) and a condenser (to be used in the process again). The turbine is connected to a generator to produce electricity.
The emission limit standards for coal and biomass combustion depend on the nominal heat power of the source. The higher the power, the more rigorous are the standards. For coal or biomass combustion, standards are set for: sulfur dioxide, nitrogen oxides, and dust. Whereas, for waste incineration, the following com-pounds must meet the standards: organic comcom-pounds expressed as total organic carbon, hydrogen chloride, hydrogen fluoride, carbon monoxide, heavy metals, dioxins, and furans. Emission standards for waste in-cineration are more rigorous than for coal or biomass combustion. Based on the data from Table 1, we can conclude that emissions of hazardous substances from
The environmental impact of waste incineration
plants
This section presents the potential risks to the en-vironment and human health, which can occur while a waste incineration plant is operating. To determine environmental impact, the LCA (Life Cycle Assessment) method is often used. LCA facilitates the decision mak-ing process and determination of a product or a process, which has the smallest environmental impact. In the life cycle assessment, the risks over the lifetime of a prod-uct are analyzed. Such an approach is called “from the cradle to the grave” analysis. In the LCA technique, the product can be an object, whole process or service. LCA enables the assessment of environmental impacts at each stage of a product’s lifetime, which include:
• extraction and processing of mineral resources,
• production process,
• distribution,
• transport,
• operation,
• preparing for re-use,
• recycling,
• final waste disposal (Grzesik, 2006).
The LCA technique takes into account all ecosys-tems and their elements to determine the environmen-tal impact of all components considered in the analysis. Thanks to such an approach, no aspect of production, operation or disposal will be neglected. More informa-tion about the detailed definiinforma-tion, structure, tasks and targets are shown in the publication of Grzesik (2006).
Cherubini et al. (2009) indicated the following op-tions in their publication on the life cycle assessment of selected waste management strategies:
• landfilling with biogas production,
• landfilling without biogas production, an incineration plant must be much smaller than in coal
or biomass combustion plants.
Poland, as a member of European Union, is obliged to obey European law. European law is implemented through national legal acts. EU documents regulating waste management are e.g. Directive 2008/98/EC of the European Parliament and of the Council of 19 No-vember 2008 on waste and repealing certain Directives, and Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial emissions (integrated pollution prevention and control). In order to exchange information about applied niques, current emission and consumption levels, tech-niques taken into account while setting best available techniques (BAT) and BAT conclusions, BAT reference documents were formed. Information on waste man-agement is included in the Reference Documents on the Best Available Techniques for “Waste Incineration” and “Waste Treatment Industries”.
Table 1. Emission limit values for waste incineration, bituminous coal and biomass combustion plants Source: Journal of Laws of 2014, item 1546. Nominal heat power of the source in MW Name of the substance
Bituminous coal Biomass Waste
Emission limit standard in mg/ m3 with 6% amount of oxygen
in exhaust gases
Emission limit standard in mg/ m3 (for dioxins and furans in ng/
m3) with 11% of oxygen in
ex-haust gases, average daily
> 100 Sulfur dioxide 400 400 50
> 50 and < 500 Nitrogen oxides 500 400 200
> 50 and < 500 Dust 100 100 10 - Organic compounds - - 10 - Hydrogen chloride - - 10 - Hydrogen fluoride - - 1 - Carbon monoxide - - 50 - Cadmium + thal-lium, mercury - - 0.05
- Sb, As, Pb, Cr, Co, Ni,
Cu, Mn, V - - 0.5
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nishes, while waste containing arsenic comes from wood treatment. Waste incineration plants cause greater risk from an air emission point of view, especially as nitro-gen oxide emission is much higher during incineration than landfilling. Incineration plants release significant amounts of carbon dioxide during incineration, while large amounts of methane are emitted at landfills. Both compounds are greenhouse gases (GHG), but methane has a higher global warming potential (GWP), which means that its climate change impact is more signifi-cant. In the ecotoxicity category, landfills have a greater impact on the environment because of the dispersion of heavy metals in the groundwater. The environmental impact from incineration plants is direct and obvious. Landfilling is a long-term process and this is why it is not always possible to observe its environmental im-pact. The LCA analysis allows the whole process to be understood and to look from a broader perspective on the actual risks arising from waste management (Mor-selli et al. 2008).
As was mentioned before, solid residues, i.e. slag, bottom ash, and fly ash from the exhaust gas clean-ing system, pose the greatest problem threatenclean-ing the environment. However, after applying the best avail-able techniques appropriate for the specific application, the environmental impact of harmful substances can be significantly decreased. According to Quina et al. (2009), the most often selected option in fly ash man-agement in practice is disposing of it in hazardous waste landfills. Such a solution is applied in Canada, Sweden, and the Netherlands. In Japan, the thermal treatment of residues dominates. The most important environmental risk of ash landfilling is the long- and short-term leach-ing of contaminants. To select the appropriate method of treatment or application of the residues, a sample should be tested, especially its chemical properties. The principal elements which can be found in ash are: Si,
• sorting with alternative fuel production for energy production and biogas in anaerobic digestion,
• waste incineration.
Their assessment considered the waste stream from the largest Italian city, Rome. The results showed that landfilling (both with and without biogas production) is the worst waste management option. Even incineration, compared to landfilling, is better, also from an environ-mental point of view. The adverse aspects of landfilling are mainly:
• low mass reduction of disposed waste,
• presence of heavy metals transferred to the soil,
• emission of landfill gas (consisting of CH4, H2S, HCl, and others).
The results showed that a sorting plant with energy and biogas recovery could be the best option in waste management, despite the significant problem of local emissions (i.e. nitrogen oxides, dust, heavy metals, poly-cyclic aromatic hydrocarbons) related to alternative fuel use. This means that according to this analysis, waste incineration is not the worst waste management meth-od, but it is not the best one either. However, none of the presented scenarios can completely eliminate landfill-ing (Cherubini et al. 2009).
In the publication of Morselli et al. (2008), an LCA analysis is presented for the incineration plant in the Emilia Romagna region (Italy). It was found that the largest impact on human health is from residue disposal (bottom ash, fly ash), mainly because of the long-term leaching of toxic substances into the soil and water. An-other, smaller risk is its direct emission into the atmos-phere. A comparison of the environmental impact (also concerning climate change) between landfilling and waste incineration was also conducted. It turned out that the emission of carcinogenic substances (cadmium, arsenic) is higher during landfilling. Waste containing cadmium can be found in the formulas of many
var-Al, Fe, Ca, Mg, K, Na, and Cl. The most often occurring heavy metals are Cd, Cr, Cu, Hg, Ni, Pb, and Zn, while Zn and Pb are present in the largest amounts. Toxic substances like PAH, dioxins, and furans are present in trace amounts. Methods of treatment of the residues from exhaust gas cleaning can be divided into three types: separation, stabilization, and thermal methods. In practice, separation techniques can precede stabili-zation or thermal methods. Thanks to separation meth-ods, the amount of pollutions can be decreased, while stabilization decreases leaching ability. Separation techniques include: washing, leaching, electrochemical processes, floculation/filtration, ion exchange, crystal-lization/evaporation, and others. Thermal methods in-clude: vitrification, sintering, and fusion. Stabilization techniques include: stabilization with or without addi-tives, stabilization with binders, and others. Options, in which the residues can be applied, may be divided into four groups: construction materials (cement, concrete, ceramics, glass), geotechnical applications (road pave-ment, embankments), agriculture (soil amendment), and miscellaneous (sorbent, sludge conditioning) (Qui-na et al. 2008).
In Poland, the only one running municipal waste in-cineration plant is the Municipal Waste Treatment Plant (ZUOK) in Warsaw. To meet the emission limit stand-ards, the process of cleaning exhaust gases in ZUOK is performed in the following three stages:
• decreasing the amount of NOX with non-catalytic reduction,
• precipitation of SOX, HCl, HF, and fly ash by an ab-sorber,
• precipitation of heavy metals, dioxins, furans, and other organic compounds in the adsorption pro-cess with active carbon (Pikoń, Galica 2007). Thanks to this cleaning system, the plant meets all the requirements of emission limit standards shown
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Fig. 5. Municipal waste management in 2012 in EU and other countries
Source: Eurostat.
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in table 1. Emissions from ZUOK are comparable to emissions from a typical combined heat and power (CHP) plant with coal combustion. The residues, such as slag, bottom ash, and fly ash undergo the stabiliza-tion processes. Thanks to these processes, pollutants are effectively bound and leaching is impossible. Resi-dues treated with such methods can be disposed of in landfills. According to the IPPC permit, the installa-tion does not produce wastewater. Rainwater is directed into a discharge canal and then into the Bródnowski Canal, while wastewater from the plant is directed to cool exhaust gases in a closed cycle. ZUOK meets all the requirements of Polish and European law and also the guidelines of the European Commission Document on Best Available Techniques in Waste Incineration. Solid waste from composting, which goes straight to the land-fill, and wastewater directed to the canal, pose a threat to surface water. Another problem is the odor from the installation, even though deodorization devices are in-stalled. Although the incineration plant is ecologically disruptive because of its air emissions and the indirect impact on water and soil, it does not pose a greater risk than CHP plants with coal combustion (Pikoń, Galica 2007).
Comparison with the world’s incineration plants
Figure 5 shows the waste treatment methods (land-filling, incineration, recycling and composting) in member states of the European Union and also in Swit-zerland, Norway, and Iceland in 2012. As mentioned before, the least desirable treatment in the waste hier-archy is disposal; however, this is the principal meth-od of waste management in most European countries. Jointly in all member states in 2012, the highest amount of municipal waste was landfilled (42%). 34% of waste was recycled and composted, and 24% was incinerated.Only 1% of municipal waste was landfilled in Germany, Belgium, Sweden, Netherlands, and Switzerland, while in Romania, 99% was disposed of in landfills. Over 50% of waste was incinerated in Norway, Sweden, Denmark, and Switzerland. Bulgaria, Cyprus, Greece, Latvia, Croatia, Malta, and Romania had no municipal waste incineration plants (Eurostat).
Municipal waste incineration is a controversial waste management option in many countries. Nations like Denmark and Japan incinerate over 65% of mu-nicipal waste. Technical and economic issues classify incineration as a secondary option in waste manage-ment in countries like China, where waste is landfilled. However, waste incineration practices are expanding in China, especially in regions where the economy is more developed and it is difficult to locate landfills (Zhao et al. 2012).
In France, over 31% of generated municipal waste is incinerated. At present in France, there are over 120 waste incineration plants in operation. Waste incinera-tion still is and will be the predominant waste manage-ment option in France (Beylot, Villeneuve 2013).
One of the most well-known waste incineration plants is Spittelau in the center of Vienna. This plant began operating in 1971. In 1987, a fire destroyed part of the installation. After this incident and also citizens’ criticism, the shutdown of the plant was considered. However, a compromise was achieved in which the in-cineration plant was rebuilt and modernized with the application of modern technologies, e.g. including the reduction of dioxin and furan emissions. The incinera-tion plant is a part of a CHP system and the produced heat is transferred directly to an adjacent hospital (Pająk 2009).
Experience showed that applying several waste man-agement methods, which are combined in a consistent system at the same time, allows successful municipal
waste management to be achieved. The characteristic features of Vienna’s waste management system are:
• separate collection of usable fractions (glass, me-tals, paper and others),
• composting,
• landfilling of problematic waste (electronic equi-pment waste) and hazardous waste,
• recycling center,
• energy recovery in waste incineration plants,
• protected and monitored landfill with biogas reco-very,
• market for recovered usable materials and energy,
• exchange of recovered waste, which possesses usa-ble value (Pająk 2009).
Additionally, the system is supplemented by a sew-age treatment plant and hazardous waste incineration plant.
In addition to the above-mentioned model, there are actions aimed at avoiding or reducing the stream of generated waste and improving the ecological aware-ness of residents.
The one landfill existing in Vienna finally completes the waste management system. It has been operating since 1978 and from this time has been effectively pro-tected and modernized. In 1991, the biogas recovery installation was built, which directs the electricity pro-duced into the urban network (Pająk 2009).
As mentioned before, Poland has only one waste incineration plant – ZUOK in Warsaw. The following processes take place at the plant:
• waste segregation with secondary raw material re-covery,
• incineration of waste which cannot be recovered,
• organic waste composting,
• slag and ash transformation into granules used in the construction industry,
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In addition to the incineration process, other pro-cesses take place at the Polish incineration plant, which make it comparable to the Vienna waste management system.
Conclusions
In Poland, the prevailing option of municipal waste management is still landfilling, which is the least desir-able method in the waste hierarchy. Additionally, ac-cording to the project of the Regulation of the Minister of Economy of 19 May 2014 on the permitting of waste disposal at landfills, as of 01.01.2016, municipal wastes with a heating value higher than 6 MJ/kg cannot be dis-posed of at landfills for inert and non-hazardous waste. Such waste will have to be treated in other ways and one of the options, is energy recovery in the incinera-tion process. Waste incineraincinera-tion plants must meet rig-orous requirements related to atmospheric emissions, which means that their negative impact on the air is not greater than in the case of coal or biomass combustion. Another aspect posing a risk to the environment is the residue from the incineration process – slag, bottom ash, and fly ash. However, after applying the best avail-able techniques appropriate for the technology, the im-pact of hazardous substances on the environment can be greatly reduced. Experience in investing and operat-ing waste incineration plants is lackoperat-ing in Poland. At present, only one plant exists – ZUOK in Warsaw. This installation meets all requirements related to emissions of pollutants and its environment impact is comparable with plants that combust coal or biomass. Few waste in-cineration plants are in the construction phase today in Poland. Each of them experienced social protests. As the plant is being built, public consultations are being car-ried out, increasing participants’ knowledge about in-cineration technology. After such consultations in
Szc-zecin and Bydgoszcz, most of the surveyed participants, supported the proposed project (Blachowska, Cichocki 2011). In Kraków, 86% of respondents definitely support the construction of a thermal waste treatment plant and consider landfills as the worst waste management op-tion when considering the impact on the environment (ZTPO 2008).
References
Beylot A, Villeneuve J (2013). Environmental impacts of residual Municipal Solid Waste incineration: A comparison of 110 French incinerators using a life cycle approach. Waste Management, 33: 2781-2788.
Blachowska E, Cichocki T (2011). Dobre praktyki konsultacji
spo-łecznych w projektach indywidualnych realizowanych w latach 2007-2013. Available at http://www.funduszeeuropejskie.gov.pl,
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Cherubini F, Bargigli S, Ulgiati S (2009). Life cycle assessment (LCA) of waste management strategies: Landfilling, sorting plant and incineration. Energy, 34: 2116-2123.
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Grzesik K (2006). Wprowadzenie do oceny cyklu życia (LCA) – no-wej techniki w ochronie środowiska. Inżynieria Środowiska, 11: 101-113.
Morselli L, De Robertis C, Luzi J, Passarini F, Vassura I (2008). En-vironmental impacts of waste incineration in a regional system (Emilia Romagna, Italy) evaluated from a life cycle perspective.
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Pająk T (2009) Po wiedeńsku, czyli kompleksowo traktowane odpady. Available at https://www.funduszeeuropejskie.gov.pl/ndr/strony/ opracowania_ndr.aspx, accessed 03.10.2014.
Pikoń K, Galica K (2007). Spalanie odpadów komunalnych – ana-liza przypadku. Archiwum Gospodarki Odpadami i Ochrony
Środowiska, 5: 71-90.
Quina M, Bordado J, Quinta-Ferreira R (2008). Treatment and use of air pollution control residues from MSW incineration: An over-view. Waste Management, 28: 2097-2121.
Socotec Polska (2009). Environmental Impact Report for project:
„Bu-dowa Zakładu Termicznego Przekształcania Odpadów przy ul. Giedroycia w Krakowie” as the element of the project: „Program
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prob-lemów gospodarki odpadami. Available at
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Act of 14 December 2012 on waste (Journal of Laws of 2013, item 21, amended).
Directive 2008/98/EC of the European Parliament and of the Council of 19 November 2008 on waste and repealing certain Directives. Directive 2010/75/EU of the European Parliament and of the Council
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Compatability with
the Polish core curriculum:
Supplementary subject Nature, IV educational stage Educational goals – general requirements:
Understanding the scientific method involving posing hypothe-ses and their verification by means of observations and experi-ments.
Contents of education – detailed requirements: 1. Environment and nature protection:
15.4. sustained development as the only alternative for the world future.
Chemistry, III educational stage, basic scope Educational goals – general requirements Contents of education – detailed requirements: A student:
1) provides examples of packaging (cellulose, glass, metal, plastic) used in everyday life; describes,
3) justifies the need to manage waste coming from various packa-ging types.
Geography, IV educational stage, extended scope Educational goals – general requirements:
III. Proposing solutions to problems occurring in geographical environment, in accordance with the idea of sustained balance and cooperation principles, international included.
A student indicates proposals for local, regional and global so-lutions of environmental, demographic and economic problems consistent with the idea of sustained balance and based on equal principles of co-operation between regions and countries. Contents of education – detailed requirements:
6. Spheres of Earth – pedosphere and biosphere. A student: 6) discusses basic principles of sustained development and judges
possibilities of their realization on a local, regional and global scale.
