DEFRA looks to establish ‘decision tree’ to specify treatment of hazwaste

The Environment Department (DEFRA) and Environment Agency have embarked on another attempt to raise hazardous waste treatment standards.

A "decision tree" specifying how hazardous waste should be treated could be in place within two years. A group has been set up by the Environment Department (DEFRA) and Environment Agency to draw up the document - the latest attempt to improve standards in the sector.

Under the landfill regulations introduced in 2005, all hazardous waste destined for landfill has to be treated to ensure it meets landfill waste acceptance criteria. However, there has been little change in the way hazardous waste is managed since.

The one exception was the closure of mixing pits in November (ENDS Report 401, p 19 ). These were a crude form of treatment that involved mixing wastes such as air pollution control (APC) residues from incinerators with a neutralising substance - often using a digger. In 2006, some 150,000 tonnes of hazardous waste was treated in them, according to the Agency.

All of the UK’s nine mixing pits closed in November, following a ban by the Agency. Most have now been replaced with above-ground vessels capable of mixing wastes more thoroughly (see table). The vessels are fully enclosed and abated. For example, Augean has replaced the pit at its Cannock facility near Birmingham with a cement solidification process capable of treating 100,000 tonnes of waste a year. In the plant, containers of solid or sludgy hazardous waste are passed through a shredder before being mixed with cement, APC residues and liquid wastes. The resulting material is sent to hazardous waste landfill.

All other operators said their processes were similar, but capacity varied from around 100,000 tonnes in the case of Castle Environmental, to 36,000 in the case of Red Industries. All operators said they also expected to treat non-hazardous wastes in the plants to make up capacity.

Last year, the Agency tried to use its classification and coding guidance for hazardous waste to raise treatment standards. This said all hazards in a waste would have to undergo treatment for the waste to be defined as non-hazardous. However, the move was poorly received by industry (ENDS Report 395, pp 22-23 ).

The Agency then proposed to define ‘best available techniques’ for individual waste streams. This was welcomed, but the Agency has realised it would become bogged down in arguments over the definition of individual wastes.

It has now decided to take a different tack working jointly with DEFRA. In March, two groups were established - a high level steering group chaired by DEFRA with the Agency, the Environmental Services Association and the Chartered Institution of Wastes Management as members, and an industry working group chaired by the Agency. The industry group is developing the "decision tree" for the management of hazardous waste, with work on this being led by Gill Weeks, Veolia’s regulatory affairs director. It aims to have the document completed in two years.

"We all support the Agency’s aim to raise the bar and its view that current practices are unsustainable," said Ms Weeks. "The main aim is to move material up the waste hierarchy", she added. "Anything that can be recovered - like oily sludges or rags - shouldn’t be going to landfill but for energy recovery." This could include processes like thermal desorption (ENDS Report 395, p 18 ). The group also aims to push biodegradable hazardous wastes, such as contaminated soils, out of landfill, she said.

The decision tree will consist of broad categories of wastes and then a list of options for their disposal. It is hoped the group will avoid arguments over waste definitions by keeping the categories broad. "We don’t want to be spending time arguing how much metal content is needed for contaminated soil to be considered inorganic," said Ms Weeks.

The roadmap has wider backing than past initiatives. However, several firms ENDS spoke to said it needed to be backed by legislation. "It’s critical that this will be enforceable by the Agency," said Gene Wilson, Augean’s technical director. "There’s no point developing a roadmap if people don’t have to follow it."

DEFRA has also started work on a national planning statement for hazardous waste, as required by the Planning Act (see p 21 ). The statement will set out what facilities are needed and what criteria should be used in judging applications. It is expected to resemble a statement of need that appeared as an annex to last year’s Waste Strategy (ENDS Report 387, pp 16-17 ).

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