Published on 8 September 2025

Municipal waste incineration plants (MWI)

Combustible waste from households, industry and businesses that is not suitable for recycling is burnt in municipal waste incineration plants (MWIs), the heat released being used to generate electricity and heat buildings.

Every year, around four million tonnes of unrecyclable combustible waste is generated by households, industry and businesses in Switzerland. In the last century, such waste was still deposited untreated in landfill sites, with the result that environmentally harmful emissions were released into the air, soil, lakes and rivers and groundwater. Facilities for incinerating waste were developed as an alternative to this practice, and the first waste incinerator began operating in Zurich in 1904. As early plants only had rudimentary flue gas cleaning, they released considerable emissions into the air and gained a bad reputation. Then in the 1980s and 1990s, the Environmental Protection Act and associated ordinances on air pollution control and water protection were passed, and existing incinerators were renovated or replaced. All new plants are now equipped with advanced state-of-the-art efficient flue gas and wastewater treatment systems. Waste incineration in Switzerland is thus now an environmentally friendly method of disposing of combustible waste and, together with separate collection and recycling, forms the backbone of Swiss waste management.

Why do we incinerate waste?

Swiss waste policy aims to recycle more waste as a means of boosting the circular economy. For combustible waste that cannot be recycled due to technical or economic constraints, incineration is the best disposal method for the following reasons:

• Combustion residues are deposited. When waste is incinerated, its volume decreases by around 90 per cent, thereby reducing the amount of landfill space required.
• During thermal treatment, organic pollutants are largely destroyed and the remaining pollutants are chemically and physically bound within the combustion residues so that they are not released even long after they are deposited.
• The carbon contained in waste produces carbon dioxide (CO₂) during combustion, which is less harmful to the climate than methane (CH₄), a gas which is released over decades from waste in landfill. In order to achieve climate neutrality by 2050, there are plans to equip MWIs with carbon capture and storage (CCS) systems. This should massively reduce carbon emissions and the harmful effects of waste incineration on the climate.
• The heat generated in MWIs is used to produce electricity and district heating. In 2024, MWIs met just under 3% of Switzerland’s total energy needs.

Recovery of metals from MWI residues: an important factor in the circular economy.

Incineration in MWIs is not the final stage of waste treatment. Every year, over 800,000 tonnes of combustion residues containing recyclable metals are generated from furnaces and flue gas cleaning systems. These residues are treated to recover over 60,000 tonnes of steel scrap, 6,000 tonnes of copper, 17,000 tonnes of aluminium and even 300 kilograms of gold every year. Currently, approximately 50% of the metal in MWI bottom ash can be recovered, the remainder going to landfill along with the mineral residues. A conference held on 29 September 2023 by the FOEN’s Waste and Resources Division focused on the importance of metal recovery from MWI residues. Further information can be found here:

Recovering metals from waste incineration plant slag – An industry in transition

How much waste incineration capacity is required in Switzerland?

Under the Environmental Protection Act (EPA), the cantons are responsible for planning waste disposal. This involves forecasting waste volumes and estimating the waste treatment facility capacity required to deal with this waste. Predicting the amount of waste that will be generated is a difficult task, as it depends on factors such as the economic situation, population growth and measures to prevent waste and promote recycling. MWIs need to have sufficient incineration capacity to ensure reliable waste disposal yet overcapacity should be avoided, as this leads to inefficient operation.