Reducing the landfilling of biodegradable and other wastes: call for evidence

5. Background: waste management

Scotland generated around 10.2 Mt of waste in 2022. Around 2.3 Mt of this was from households, 3.2 Mt from commercial and industrial sources, and 4.6 from construction and demolition activity.

Everyone handling waste has a duty to ensure it is managed according to the waste hierarchy, which prioritises management options according to their environmental impacts. Where discarding materials is unavoidable, priority is given to reuse of materials and then recycling. Around 62% (6 Mt) of all waste and 43.7% of household waste was recycled in 2022^[5][6]. Where materials cannot be reduced or recycled the waste hierarchy favours energy recovery, for example via energy from waste processes, and then landfill is the least preferable option, reserved for wastes which cannot be recycled or recovered.

There has been a significant decrease in the amount of residual waste sent to landfill over the past ten years, driven by factors including Scottish Landfill Tax, and the forthcoming ban on landfilling biodegradable municipal waste. Scotland’s previous targets focused on tracking reduction of overall waste generated (to reduce waste generated by 15% between 2011 and 2025) and reducing the amount of waste being sent to landfill (send a maximum 5% of all waste to landfill by 2025). Official waste statistics published annually by SEPA^[7] provide the data to assess progress against these metrics. Based on the most recent data (2022), we have met our overall waste reduction target. However, the total amount of waste we generate in Scotland varies greatly from year on year, largely due to differences in waste from construction and demolition. The amount of all waste landfilled has decreased from 7.1 Mt to 2.4 Mt between 2005 and 2022, and Scotland landfilled 23.2% of all of its waste in 2022. However, as we set out in the Route Map, the 5% to landfill target does not account for the carbon intensity of waste being diverted to landfill, and is not a good indicator to measure the sector’s progress to net zero.

The Route Map sets out our intention to set new circular economy targets to 2027. As we set out what comes next, we recognise the role previous targets have played, and the lessons we can learn moving forward.

Biodegradable municipal waste to landfill and greenhouse gas emissions:

The amount of biodegradable municipal waste sent to landfill has also decreased and Scotland exceeded the EU target, to landfill less than 25% of the biodegradable municipal waste in 1990^[8] by 2020. We expect further decreases in the amount of biodegradable municipal waste landfilled as we approach the ban on landfilling biodegradable municipal waste from 31 December 2025.

This decrease in landfilling biodegradable waste has supported a decrease in waste management sector emissions from 6.5 million tonnes of carbon dioxide equivalent (MtCO2e) to 1.6 MtCO2e between 1990 and 2022, which now only directly account for around 4% of Scotland’s total greenhouse gas emissions, although this does not include emissions from EfW, which are reported under the electricity sector. Our Climate Change Plan update (2018-2032) set out an ambition to reduce greenhouse gas emissions from the waste management sector to around 0.9 MtCO2e per year by 2025, and to 0.7 MtCO2e per year by 2030.

The release of methane from landfill accounts for 78% of all waste management sector emissions (which excludes emissions from energy from waste facilities). Further diversion of biodegradable waste is therefore important to achieve our climate ambitions.

Alternative treatment options:

This reduction in landfilled waste has been achieved through a combination of investment in energy from waste infrastructure in Scotland, lower waste arisings and an increase in recycling rates.

Investment in EfW infrastructure has led to an increase in the amount of waste incinerated. The total quantity of waste incinerated in 2022 was 1.42 Mt, an increase of 1.01 Mt since 2011. This increase has been accompanied by an increase in GHG emissions from EfW, which are reported under the electricity sector in the GHG Statistics, to 0.3 MtCO2e in 2022, comprising around 19% of electricity sector emissions.

The biostabilisation of waste prior to landfill through mechanical biological treatment (MBT) is also an alternative route to treat waste. While a small amount of waste is managed through MBT–like systems, we are not aware of recent investment in MBT technology in Scotland.

Where landfill remains the best treatment option:

For a number of waste streams landfill represents, or is highly likely to represent, the best environmental outcome for that waste. This includes, for example, wastes like asbestos, certain stabilised ashes and sorting residues that are unsuitable for energy recovery and cannot be further sorted into usable fractions.

It is therefore important to note that while our aim is to manage waste as high up the waste hierarchy as possible, some landfill capacity is still vital to manage all of our own waste in a way that protects the environment and public health.