By Ned Van Steevis
Sweden has been praised for its highly effective waste management systems. Over the past two decades or so, Sweden has consistently maintained a recycling rate well over 40% and only landfilled close to 1 or 2%. The system relies heavily upon much waste being incinerated in ‘waste-to-energy’ plants which, along with other biofuels, supply 29.4% of Sweden’s total energy. The Swedish waste model has served as a very useful and competent design for managing the worldwide problem of waste management. But Sweden itself needs to further progress with its waste management and not continue to let its efforts stagnate.
Landfills engender several problems. Methane produced from anaerobically decomposing waste in landfills accounts for just over a quarter of total methane emissions in the UK. Not only is methane ~80 times more potent per tonne than carbon dioxide over 20 years in the greenhouse effect, but also often forms ground-level ozone, a harmful air pollutant and itself a greenhouse gas. Owing to methane’s short atmospheric lifespan, ‘cutting methane emissions is one of the fastest and most cost-effective tools available to limit global temperature rise’ according to the UK government. Other organic gases given off from landfills, such as benzene, can also be harmful to human health. Leachate, liquid that leaches solid as it percolates through a substance carrying it by suspension or solution, from landfills also contaminates groundwater and soil with pollutants such as heavy metals and ammonia.
Capturing methane emissions and using them to generate electricity is a proposed solution for landfills in the UK. But Sweden offers another idea: simply landfilling less. In 2023, Sweden managed to landfill only 1.5% of all its household waste while England landfilled 7.2% that year. Sweden’s volume tax then subsequent banning of all landfilling in the country in 2005 led Sweden to instead heavily invest in waste-to-energy facilites, each with a capacity to burn 7.1 tonnes of non-recyclable waste a year but intended to burn less. In fact, Sweden’s facilities have grown to overcapacity now needing to import waste from other countries such as the UK to continue running. Landfill waste has a lot of energy potential. Approximately four tonnes of waste are equivalent in energy potential to 1.6 tonnes of coal or a tonne of oil. These facilities can also run well when integrated with seawater desalination plants, enormously helpful to areas affected by drought where landfills may burst into flame anyway – landfill fires being frequent – emitting various hazardous fumes. Moreover, as of 2023, the UK had just shy of only 326 cubic metres of landfills space remaining. Waste-to-energy incineration, whilst by no means a perfect solution, can act as a very good transition tool.
Incineration should of course be seen as a secondary priority to recycling itself. After filtering and scrubbing toxic gases from waste-to-energy incineration, carbon emissions are much greater than other fuels – waste produces close to 1.35 tonnes of CO2 equivalent per megawatt hour of electricity while coal is close to 1 CO2e/MWh and natural gas close to 0.5 CO2e/MWh. However, 2/3 of these CO2 emissions from waste would have been naturally released, making waste in this sense competitive with natural gas and far better than coal. But this is still undesirable. Incombustible residue or slag leftover makes up ~15% of the waste burned some of which can be reclaimed for metals and aggregate but most of which must be landfilled. The toxic remains of scrubbed fumes also cannot be currently used for any further purpose. There is also doubt over whether the scrubbing of gases is 100% effective which means not just CO2 and steam may be being put in the air.
Swedish recycling is effective. In 2023, Sweden reused or recycled 42.5% of its waste. Just over 35% of this recycled waste underwent biological treatment either by composting or anaerobic digestion. Anaerobic digestion utilises micro-organisms to convert waste into useful products also releasing biogas, a renewable energy source comprising about 60% methane and 40% carbon dioxide. If it is refined, it can also be used for transportation fuel. Anaerobic digestion also can produce a highly nutritious fertiliser. Most of the rest of the waste recycled is merely reused for construction and other purposes. As regards wastewater, Sweden amazingly reuses 64.5% of ‘urban wastewater sludge’ in agricultural and other soil-related uses. Furthermore, on average, Sweden generated 449 of household waste per person in 2022 compared with the European average of 513kg.
Nonetheless, apart from Sweden’s remarkably low landfilling rate, the rest of its waste management system is no longer as incredible. China’s unexpected ban on importing waste in 2018, having been the world’s largest importer of waste plastics until then – it had imported cumulatively 45% of plastic waste since 1992 – exposed the dysfunctional nature of many recycling systems globally. For instance, 41% of ‘recycled’ goods in Canada were exported for recycled in other countries before China’s ban. In the wake of this dent to global waste trade, Sweden provided an exemplar for others to follow. But Sweden no longer stands above other nations. In 2023, the UK recycled 40.7% of its household waste and incinerated for energy 48.7%, less than Sweden largely owing to more landfilling but not enormously so. Moreover, in 2022, the UK generated about 377kg of household waste per person, 72kg less than Sweden in the same year as cited above.
Sweden’s recycling rate has been about the same since 2006. Their targets remain optimistic – to recycle and prepare for reuse 55% of municipal waste by 2025 – but what they have achieved with solid waste does not seem to be progressing. To continue to export their model to the world, changes to their incineration methods should be investigated such as using acid electrolytes or hot plasma instead of brute thermal energy to dispose of non-recyclable waste. However, much more significant is the fact that Sweden’s economy is largely funded by manufacturing and mining industries which provide problems for Sweden to manage its commercial waste. Using what it has learnt from municipal waste management and applying this more fully to commercial waste management, Sweden should be able to continue to remain outstanding with its waste management model.
Bibliography
A.L. Brooks, S. Wang and J.R. Jambeck, ‘The Chinese Import Ban and its Impact on Global Plastic Waste Trade’, Science Advances, Vol.4 No.6, 2018
Simon Copping, Cara Quinn and Robert Gregory, Review and Investigation of Deep-Seated Fires within Landfill Sites (Bristol: Environment Agency, 2007)
Huira Ma et al., ‘Catalytic Ozonation of Ammonia Nitrogen Removal in Wastewater: A Review’, Journal of Water Process Engineering, Vol.52, 2023
M.C. Sarofim, S.T. Waldhoff, and S.C. Anenberg, ‘Valuing the Ozone-Related Health Benefits of Methane Emission Controls’, Environmental and Resource Economics Vol.66, 2015
Ken Udono and Renate Sitte, ‘Modeling Seawater Desalination Powered by Waste Incineration using a Dynamic Systems Approach’, Desalination, Vol. 229 Nos. 1-3, 2008
https://www.avfallsverige.se/in-english/swedish-waste-management/treatment-methods/
https://www.data.gov.uk/dataset/237825cb-dc10-4c53-8446-1bcd35614c12/remaining-landfill-capacity
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