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Watching the waste line

Waste management has forced its way onto the engineering agenda, discovers Andrew Mylius.

Four months after the codisposal of hazardous and inert waste in landfill sites was banned, predictions of soaring waste management costs are being borne out. Director of remediation specialist Vertase, Clive Barnwell, says that on introduction of the European Union's Landfill Directive, which enforced the ban, 'overnight, landfills licensed to accept hazardous waste dropped from over 240 to less than 10.

'Pre 16 July, hazardous waste disposal typically cost £15/t and distances travelled from site to landfill were less than 45km. Post 16 July we are paying £85/t and hauling the waste over 225km.'

Hazardous waste arises from a multitude of sources that include process industries, car breaking and scrap metal, the construction and demolition industries, waste water treatment, land remediation and dredging, among many others.

Barnwell reckons it will take at least two years before the operators of landfill sites commit to the construction of new sites capable of accepting hazardous wastes. These will need to be heavily engineered structures with 5m thick clay linings to prevent toxins leaching into ground water, and will be subject to strict regulation.

The expense of building and operating specialist facilities has been offputting to the waste management industry; hazardous waste disposal costs will probably fall in the long term but by less than half, predicts John Galloway, planning, transport and environment director at environmental consultant RPS.

Despite the six-fold price hike, however, waste contractors have not been utterly overwhelmed, reports Andy Street, director at environmental consultant SLR. 'It may be that producers are sitting on waste - storing it up - waiting to see what happens to disposal prices, but site operators aren't as rushed as we'd expected.'

Barnwell confirms: 'Some operators are concerned about the low volumes of hazardous waste that they're attracting.' Looking at the remediation of contaminated land, there are several possible reasons for this, he says.

Many [site remediation] projects were brought forward or accelerated to beat the 16 July deadline. This typically involved excavating all contaminated soils and taking them to the nearest landfill site. But he also believes consultants and contractors are paying closer attention to waste classification in order to minimise the amount classed as hazardous.

'This can be achieved by better site characterisation and risk assessment, and it's likely that the physical layout of development schemes will increasingly be adapted to minimise the volumes of material disposed of off-site, ' Barnwell explains.

There is also a move among some developers to keep waste on site in specially engineered, landscaped areas, although to do this a waste management licence has to be obtained from the Environment Agency. This has to be kept up to date indefinitely, as the site owner effectively becomes the operator of a waste disposal site.

It is widely anticipated that alternative remediation techniques, such as bioremediation, insitu lime or cement stabilisation, gas venting or soil washing, will gain ground as cost-effective alternatives to now exorbitant landfill.

Classification and handling of hazardous wastes is far from straightforward. Since July there has been a far closer focus on the constituent parts of waste, with the type, range and concentration of controlled substances determining the method of treatment or disposal. 'For example, how should hydrocarbon contamination be evaluated? Is it the benzene - a carcinogen - concentration in petrol or the petrol concentration itself that decides the classification?'

questions Barnwell.

Debate is still simmering as to whether the level of contamination should be determined by the maximum value found on site, or by an average. Site investigations are becoming increasingly rigorous, with borehole drilling patterns far closer than in the past, says Galloway.

There are claimed to be wide variations in the interpretation and enforcement of waste classification criteria across the country by Environment Agency enforcers.

There is some hope of ironing these out with the introduction next July of new Europe-wide waste acceptance criteria, which will introduce standards for the disposal of hazardous waste across EU member states.

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