Members of the waste industry have expressed disappointment with the Department for Environment, Food & Rural Affairs’ (Defra) decision to not withdraw a derogation that allows air pollution control residues (APCr) to be disposed of as hazardous waste landfill.

APCr is the powder that is left over when the gases from energy-from-waste facilities are cleaned, consisting mostly of lime, which must be pre-treated and neutralised before being disposed of.

Under current laws, waste management companies are able to send the material to landfill even when it is up to three times above the Landfill Directive waste acceptance criteria (known as the 3xWAC derogation).

Defra had suggested in its 2010 Hazardous Waste Strategy that it planned to phase out this derogation, but after a transitional period to allow new waste management infrastructure and contracts to be developed, the department has cited a ‘lack of alternative disposal solutions’ for not withdrawing the derogation, an outcome sought by much of the industry after a consultation process.

The Environmental Services Association (ESA), which represents many members of the UK’s resource and waste management industry, says it is ‘disappointed’ with the decision, with Executive Director Jacob Hayler explaining: “Withdrawal of this derogation was first mooted in Defra’s 2010 Hazardous Waste Strategy. Since that time, ESA and its members have worked with Defra and Environment Agency officials to reach workable proposals for an orderly phasing out of the derogation and a gradual transition to new techniques for the recovery of APCr into useful products.

“While it is useful finally to have some clarity after this lengthy period, it is disappointing that ministers have decided not to phase it out after all.

“This decision won’t help investment in alternative treatment technologies for APCr which would deal with the waste further up the waste hierarchy, and potentially brings into question the government’s commitment to the waste hierarchy more generally.”

Landfilled APCr could be ‘dormant liability for future generations’

Hazardous waste technology provider Tetronics International, which worked with the now-defunct Department for Business, Innovation and Science (BIS) to fund research and development into one possible solution, plasma vitrification, to stop the waste needing to be sent to landfill, added in a statement: ‘Without removing the derogation and aligning with current European legislation the amount of APCr sent to landfill will continue to rise.

‘Already, 282,000 tonnes of APCr per year is being generated in the UK, this is enough to fill over 100 Olympic sized swimming pools and the generated volumes are growing to 600,000 tonnes a year by 2020. This hazardous waste not only needlessly fills up our landfills, but could also potentially be a risk to the environment as it is the concentrated form of pollutants.’

The company adds that withdrawing the plan to get rid of the derogation will lead to the hazardous material lying in landfills as a ‘dormant liability for future generations’.

Firms investing in APCr recycling

Waste management firm Viridor announced in 2015 that it had partnered with Carbon8 Aggregates Ltd to recycle around 25,000 tonnes of its APCr into a ‘sustainable, carbon negative aggregate’ every year.

Carbon8 Aggregates’ process involves treating the waste with carbon dioxide (CO2), which reacts with the lime content of the APCr to form a carbonated compound similar to limestone. This chemically immobilises the heavy metals present in the APCr. The treated residue is then mixed with various binders and fillers prior to being pelletised with more CO2 to form a lightweight aggregate material ranging in size from two to 20 millimetres. This can then be used in the same way as virgin aggregates, for example, for use in the production of building blocks.

Another company, Castle Environmental, invested £1 million in a new APCr recycling plant in Cardiff in 2015, also creating aggregate feedstock, and opened another facility in Stoke-on-Trent in November. The company, says it invested significantly after Defra moved to withdraw the 3xWAC derogation, but that the withdrawal will not stop it from continuing to develop the process.