7. Topic 3: Economic, Environmental and Social Trade-offs
Identifying the appropriate options for the treatment of residual waste will require consideration of a range of trade-offs between several factors including feasibility, cost, environmental impact and societal impact.
While the costs of each residual waste treatment option are likely to vary significantly depending on individual circumstances, such as location, there are some general factors that influence the cost of treatment.
In general, residual waste treatment facilities operate on a gate fee model, where a weight-based fee is charged for waste received at a facility. Although there is a range of gate fees across treatment types, a recent report indicates that median gate fees in 2020 were around £93/tonne (range: £48 - £150) for energy from waste (UK figure) and £30/tonne (range: £10 - £93) for Scottish landfill sites. Deposits at landfill sites in Scotland are also subject to Scottish Landfill Tax. Scottish Landfill tax is charged by weight based on two rates, a standard rate (£96.10/tonne) and a lower rate (£3.10/tonne) for less polluting materials (referred to as qualifying materials).
We are not aware of any recent estimates of gate fees for MBT facilities, although a 2017 report notes that 'the 5 authorities with the most expensive total waste management cost per tonne of Residual Waste had primarily contracted an MBT based Residual Waste solution' and estimated gate fees were higher (£125 - £135/tonne) than previously reported (£88/tonne).
The Review would welcome Scotland-specific data on the costs associated with residual waste treatment, as well as the costs associated with other options that are not widely operational in Scotland, such as biostabilisation.
Q12 What data can you share with the Review on the costs of operating any options for managing residual waste in Scotland, especially costs based on real experience?
In addition to the costs of managing waste, there are wider costs associated with different waste treatment options. For example, the aftercare of landfills is necessary to mitigate the environmental impacts of sites after closure. In addition, there are other costs associated with closed landfills, for example, remediation costs associated with erosion of landfills near river banks. The Review, therefore, would welcome evidence and experiences on the wider costs that should be considered, particularly examples of where these costs have been realised.
Q13 What data can you share with the Review on the wider costs associated with options for managing residual waste in Scotland, especially where those costs have materialised?
7.2 Environmental impacts
The impact of residual waste treatment on the environment depends on the chosen technology and on how it is operated. The Review would welcome evidence around what these impacts are and, where possible, the quantification of these impacts.
A Zero Waste Scotland report suggests that incinerating municipal waste in Scotland resulted in 27% fewer greenhouse gas (GHG) emissions than landfilling the same waste. Other, UK-level reports have supported this hierarchy, for example, a 2021 report noted that incineration (without pre-treatment) produces less GHG per tonne of waste treated today than landfill (without pre-treatment and bio-stabilisation). Importantly, estimates of carbon impacts are particularly sensitive to changes in residual waste composition and the scope of the analysis (e.g. whether biogenic carbon is included or excluded from the analysis).
In addition, several reportsError! Bookmark not defined.,Error! Bookmark not defined. have highlighted the potential of pre-treatment to remove recyclable materials, as a pre-cursor to landfill or incineration, as well as biostabilisation of waste as potential options to reduce the carbon impact of residual waste treatment.
Q14 Do you have any evidence that the Review should consider in comparing the carbon impacts of options for residual waste treatment? E.g. compositional analyses of waste streams, case studies, or reports on carbon impact.
There are other environmental risks from the treatment of municipal waste, such as emissions to air and water. Emissions from waste treatment sites are monitored and reported on by SEPA. In terms of environmental compliance, of the six sites accepting municipal waste for incineration in 2018 SEPA classified five as having 'Excellent' or 'Good' levels of compliance and one had 'Very poor' compliance. Of the 179 licenced landfill sites (both accepting waste and closed) in Scotland in 2018, 149 had 'Excellent' or 'Good' compliance, four were 'Broadly compliant and 26 were 'At risk', 'Poor' or 'Very Poor' levels of compliance.
Q15 What other aspects should the Review consider when assessing the environmental impacts of residual waste treatment options?
Q16 Do you have any evidence that the Review should consider in comparing the other (non-climate) environmental risks of options for residual waste treatment in Scotland?
7.3 Societal implications of residual waste treatment
The Review would like to consider the negative and positive implications for society arising from the choice of residual waste treatment.
For example, we understand that regulators receive a significant number of complaints about landfill sites and fewer about incineration facilities from the communities living near these sites. However, this may be due to the greater number of communities and people living close to landfill sites compared with incineration facilities. We would, therefore, particularly welcome any additional evidence on complaints, for example, evidence on the impacts on how people view their community, or the satisfaction that people get from their community, as well as noise and odour complaints related to residual waste treatment facilities.
Q17 Do you have evidence or experience of the community impacts (positive and negative) of different residual waste treatment options, e.g. landfilling compared to incineration, that you could share?
In terms of health, for modern incineration facilities, the evidence suggests that any potential adverse effects on health are likely to be very small.
In 2009, a review by Health Protection Scotland and SEPA noted that:
- any risk to human health associated with newer incinerators, operated within the current regulations, which are based on a precautionary approach, is likely to be minimal and very difficult to detect.
- some recent (relative to the 2009 review) work suggested that there may have been an association between some airborne emissions from industrial, clinical and municipal waste incinerators in the past before more stringent regulatory requirements were implemented. However, this evidence is not completely conclusive and is inconsistent with other previous work.
- the magnitude of any health effects on residential populations living near incinerators in the past, if it occurred, is likely to have been very small.
- due to stricter legislative controls and improved technology, the levels of airborne emissions from individual incinerators should be lower now than in the past. Hence, any risk to the health of a local population living near an incinerator, associated with its emissions, should now be lower.
More recently, there have been several studies on the health impacts of incineration, from the Small Area Health Statistics Unit (SAHSU) at Imperial College London. Following the publication of the most recent study, which included data on an incineration facility in Scotland, Public Health England noted that its risk assessment remains that
'modern, well run and regulated municipal waste incinerators are not a significant risk to public health. While it is not possible to rule out adverse health effects from these incinerators completely, any potential effect for people living close by is likely to be very small'.
Public Health England note that its view is based on detailed assessment of the effects of air pollutants on health and on the fact that these incinerators make only a very small contribution to local concentrations of air pollutants27.
However, one study suggests that there has not been enough time for adverse effects of modern incineration facilities to emerge.
In comparison to landfill, a recent systematic review suggests that emissions from, and therefore health risks associated with, incineration facilities using RDF as a feedstock are lower than landfill.
Q18 Do you have evidence (reports, studies, data) that could help to inform consideration of the public health implications of different treatment options?
There is a problem
Thanks for your feedback