Quality Report for Household Waste Generated and Managed in Scotland 2023

Revisions Policy

Revisions could occur for various reasons, including when data from third parties are unavailable or provisional at the time of publishing or if there are subsequent methodological improvements or refinements.

The figures are accurate at the time of publication. However, the data may be updated if further revisions are necessary. Normally, in line with SEPA’s published corrections policy, revisions will be published concurrent with the next release.

Where there have been changes in methodology for the waste data tables, the complete dataset is to be revised for all years to ensure that comparisons between years are valid.

Introduction

The Scottish Government’s Making Things Last – A Circular Economy Strategy for Scotland sets out the Scottish Government’s vision for a zero waste society. This vision describes a Scotland where all waste is seen as a resource, where waste is minimised, where valuable resources are not disposed of in landfills, and where most waste is sorted, leaving only limited amounts to be treated.

This policy document sets a number of objective and measurable targets for tracking progress against the objectives specified in the plan. Some of these targets are derived from EU directives such as the Waste Framework Directive. A summary of these targets are provided in Table 1 below.

The Circular Economy and Waste Route Map to 2030, Scotland’s strategic plan to deliver its sustainable resource and circular economy ambitions, was published for consultation in January 2024. The final Route Map is due to be published later this year. Its actions are complemented by provisions in the Circular Economy (Scotland) Act 2024. The Act establishes the legislative framework to support Scotland’s transition to a zero waste and circular economy, significantly increase reuse and recycling rates, and modernise and improve waste and recycling services.

Recycling/composting and preparing for re-use of household waste

The method used to prepare the household waste recycling/composting and preparing for re-use figure is based on waste from households reported in WasteDataFlow. The total waste reused, composted, and recycled for all 32 Scottish local authorities is calculated as depicted in Figure 1 below.

The meaning of household waste changed in 2011 with the introduction of the Zero Waste Plan. The household recycling figures use the revised meaning for 2011 – 2023. Changes in the definition of household waste include:

• compost like output from mechanical and biological treatment (MBT) of household wastes previously counted as recycled was re-classified as ‘Other recovery’;
• metals and ash from incineration previously counted as recycled was re-classified as ‘Other recovery’;
• street-sweeping, gully waste, healthcare waste, and beach-cleansing waste were re-classified from household to commercial waste.
• waste that failed to meet the PAS

In 2022, the definition of recycling further changed to include metals from incineration.

The preparing for re-use and the recycling by weight of waste materials such as paper, metal, plastic, and glass from household waste and similar

Previously, we reported to Eurostat under Article 11(2)(a) of the Waste Framework Directive (Directive 2008/98/EC), which specifies that member states must meet a recycling target of 50% by weight for the recycling of waste materials such as paper, metal, plastic, and glass from households. Commonly know as the “Waste from households (WfH)” calculation, Defra continue to publish these data for the UK and devolved nations as part of their UK Statistics on Waste.

The WfH calculation is depicted in Figure 2 below. The key differences between the Scotland recycling rate and the Waste from households recycling rate are summarised in Table 2 below. Further information about differences between the national recycling measures of the four UK countries may be found in the Recycling Explainer published by Defra in consultation with the environmental agencies of the four UK countries.

\[ Percentage\ household\ waste\ recycled\ =\ \frac{Household\ waste recycled}{Household\ waste\ generated} \]

\[ WfH\ generated\ (tonnes)\ =\ Household\ waste\\ generated\ -\ Soils\ and\ Construction\ waste\ recycled \] \[ Percentage\ WfH\ recycled\ =\ \frac{(Household\ waste\ recycled\ \\- Soils\ and\ Construction\ waste\ recycled generated\ \\+\ waste\ composted\ at\ non\ PAS\ facilities) *\ 100} {WfH\ Generated} \]

Introduction

This section describes how we report on household waste generated in Scotland; and Scottish household waste managed in Scotland or elsewhere. Data is taken from all 32 Scottish local authority returns using the web-based reporting tool WasteDataFlow (WDF). Further details of the WDF dataset can be found in Appendix 1. Throughout this section reference is made to question numbers on WDF.

In 2023 local authorities submitted returns annually. All returns were checked and verified by SEPA staff for data entry errors, consistency with previous returns and consistency with the site returns dataset.

All waste collected is reported in WDF in the same return period in which it is sent to management. This allows balancing of the waste generated and waste managed for a period. The waste generated figures may include treated waste stockpiled prior to final management. The waste managed figures exclude treated waste held in stockpile at the end of the reporting year.

Methodology

Waste categories

A list of SEPA reporting categories and corresponding WDF waste types are provided in Appendix 2 and Appendix 3.

For intelligibility, the official statistics commentary document for household waste generated and managed, the statistical waste categories “Metallic wastes, ferrous “, “Metallic wastes, non-ferrous”, and “Metallic wastes, mixed ferrous and non-ferrous” have been combined into the one category “Metallic wastes” , and the statistical waste categories “Mineral waste from construction and demolition” and “Soils” have been combined into one “Construction and soils” category. The Household Waste Discover Data tool retains the all the statistical categories.

Household waste generated

Household waste generated were taken from the household tonnage inputs to primary level facilities in question 100.

Household waste landfilled

Household waste sent to landfill was derived from the waste recorded as sent to a landfill facility in Q100, either directly or as secondary outputs to landfill following the treatment of waste.

Household waste recovered by incineration, recovered by co-incineration, disposed by incineration

The quantity of household waste incinerated in the Household Waste Discover Data tool is the net tonnage input to the incinerator. This is to provide consistency with the waste reported in the official statistics publication. Note that this differs from the WFAS Waste Discover Data tool, in which gross inputs to incineration¹ are reported.

Incineration tonnages were allocated to the incineration by recovery category where the incineration facility met the R1 Waste Framework Directive criteria for incineration efficiency. Similarly, where waste was incinerated in a co-incineration process, tonnages were allocated to the incineration by co-incineration category in the data tables. Where the incinerator was not recognised as meeting Annex II of the Waste Framework Directive criteria for incineration efficiency, the incineration tonnages were allocated to the incineration by disposal category. It was assumed that all waste exported outside the UK was sent for incineration by recovery, and waste exported to an England incinerator was sent to incineration by disposal or incineration by co-incineration.

Household waste recycled

The quantity of household waste recycled is the net sum of household waste recorded as sent to reprocessor facilities in Q100. This includes waste sent direct to a reprocessor from collection and also the recyclable materials sent to a reprocessor following sorting of mixed wastes at a waste treatment facility (e.g. MRFs, MBT).

Under Scotland’s Zero Waste Plan the compost-like output (CLO) from MBT of household waste, and recycled incinerator bottom ash from incineration of household waste do not count towards household recycling targets and are excluded from household waste recycling figures but they are included under “other diversion from landfill” unless these materials are landfilled.

Household waste prepared for reuse

The quantity of household waste prepared for reuse is the net sum of household waste recorded as sent to reuse facilities in Q100, either directly or as outputs from a sorting facility.

Household organic waste recycled through biological treatment

The quantity of household organic waste recycled through biological treatment is the net sum of household waste recorded as sent to organic recycling facilities in Q100. There are three categories of organic recycling facilities in Q100: windrow composting, in-vessel composting, and anaerobic digestion facilities.

In 2023 only PAS100/110-accredited facilities were considered for the recycling data in line with Scotland’s Cicular Economy policy. This change stems from the Scottish Government policy to improve quality of recycling, first introduced with the publication of the Zero Waste Plan in 2011. Waste composted or digested that has not reached the quality standards set by PAS100/110 and diverted from landfill was counted under “Other diversion from landfill”.

Household waste managed by other methods

Recycled ash from incineration (excluding metals recycled) of household waste do not count towards household recycling targets and are excluded from household waste recycling figures. These materials have been allocated into the “Other waste managed” category in the household waste data tables. Also included in this category is any process loss during waste treatment, and process loss of organic waste composted in which the compost product is disposed, and compost-like outputs from mechanical biological treatment (MBT) which are sent for recycling

Final destination reporting

The geographic allocation (Scotland / Outwith Scotland) for household recycling / disposal / recovery relies on the accurate reporting of the final destination of waste materials. For example, a final destination for glass bottles would be the site where the bottles are reprocessed into new materials. A final destination for rejected material from a MRF might be landfill or incineration.

SEPA guidance requires authorities to report the final destination of the waste in Q100 (i.e.  the facility where waste is recycled, recovered or disposed). Waste often goes through a complex chain of sites before reaching its final destination. This, together with the reluctance of some operators to report where waste is sent due to commercial confidentiality, means many authorities struggle to obtain final destination information for the WDF report.

Although the roll out of Q100 has improved final destination reporting, many authorities still continue to report MRFs as final destinations. The geographic information for household waste managed, in particular the household waste recycled, should therefore be treated with caution in the waste data tables. It is anticipated that the UK digital waste tracking service, when implemented, will provide more detailed and accurate data on the destination of waste managed by local authorities.

2011 - 2013 Composting and Other Diversion

In 2014 the meaning of recycling changed in Scotland. After 2014 waste that was composted at PAS100 / PAS110 certified facilities counted towards recycling, and waste sent to facilities which were not certified did not count towards recycling but were part of the “Other diversion from landfill” category.

From 2014 to 2019 the old and new method were published in the statistical bulletin side by side. However, as we move further away from the old composting measure, it becomes less important, and a back series is helpful for understanding changes over a long period of time. For 2011 – 2013 the waste that met the PAS 100/110 standard was modelled to produce a back series. For each authority, the proportion of waste that was sent to a PAS 100/110 facility on average in 2014-2015 was applied to the waste sent for composting for each of the years 2011, 2012 and 2013. Further information about the formula for calculating the non-PAS tonnes and the factors used for each authority may be found in the 2021 household waste quality report.

Carbon Metric

The carbon metric is a measure of the whole-life carbon impacts of waste, from resource extraction and manufacturing emissions, right through to waste management emissions, regardless of where in the world these impacts occur. The carbon impact of waste was developed by Zero Waste Scotland (https://www.zerowastescotland.org.uk/content/what-carbon-metric).

Calculation of the carbon metric depends upon the waste category and how it is managed. The waste category for each management type is multiplied by the carbon factor listed in Appendix 4. The carbon factors have, for each year up to 2021, been provided by Zero Waste Scotland, and the methodology on how they are produced may be found in the carbon metric technical reports on Zero Waste Scotland’s web site. For 2022 and 2023, the carbon factors for 2021 were used. This was done as year-on-year changes in factors are relatively minor; for example, the total carbon emissions per tonne of Animal and mixed food waste over the last five years (sum of emissions from waste generated, recycled, incinerated, landfilled or diverted) varied by less than 0.3%; and resources could be focused on developing factors for Scotland’s Waste Environmental Footprint Tool (SWEFT) tool, which is scheduled to replace the carbon metric from 2024 onwards.

The Household and similar wastes category, which comprises mixed residual waste, was first divided up into individual waste compositional categories before multiplying by the relevant carbon factor. This was achieved by using the composition of residual waste published in Zero Waste Scotland’s 2014 waste composition study. Not all Scottish local authorities were included in the 2014 waste composition study. Therefore, the average waste composition across all Scottish authorities was applied to each authority. It should be noted that the waste composition for authorities can vary, depending on the amount of source segregated collections undertaken in a local authority area. Therefore, care should be taken when comparing local authority carbon metric data.

It is almost certain that, due to the introduction of source segregated food waste collections, the food waste composition will have decreased since 2014. To account for this, the amount of food waste over segregated and residual waste streams was assumed to be constant over any year. For each year, the amount of food waste in the residual waste stream was then calculated by subtracting the amount of waste in the segregated waste stream for that year from the amount of food waste across both the segregated and residual waste streams in 2014. The final waste composition used for each year is list in Appendix 6 on page 26. It should be noted that, due to the infrequency of waste composition studies, the variation due to sampling error for waste composition is unknown. Zero Waste Scotland has a planned program for regular waste composition studies which will provide a better estimate of year to year variation of the waste composition, and, consequently the variation in the carbon metric analysis.