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PAUSE FOR THOUGHT

GEOENVIRONMENTAL ENGINEERING

Remediation on some sites could come to a standstill as a result of the next tranche of the Landfill Regulations, says Steve Branch.

Prevention or reduction of the negative environmental effects of landfill is the aim of the Landfill (England and Wales) Regulations 2002.

Implementing the 1999 EU Landfill Directive (Council Directive 1999/31/EC), the first phase of the regulations came into force on 16 July 2002. The second phase kicks in on 16 July this year.

This second phase will have a profound effect on brownfield development, on the level and type of site investigation required, and on advice developers are likely to seek from geoenvironmental consultants.

'Co-disposal' of waste - the acceptance by a single landfill site of both hazardous and nonhazardous wastes - will be banned.

Hazardous waste will have to be pre-treated and placed in newly licensed hazardous waste landfills or, if stable and non-reactive, in special 'mono-cells' in ordinary landfills.

The new regulations provide a clearer classification of contaminated soil, by setting out the standards waste must meet to be accepted at one of three classes of landfill: inert, non-hazardous or hazardous.

The classifications are defined in the Waste Acceptance Criteria (WAC) which set limits, based on the results of leaching tests, for a number of contaminants.

The WAC will be implemented on 16 July 2005 and in the meantime interim guidance will be followed and some relaxation of the controls may be allowed on a site-specific basis.

At first sight, these new rules may appear to be a matter for the landfill operators. But the geotechnical and geoenvironmental community, civil and structural engineers, main contractors and developers should not assume they will be unaffected.

Many practitioners will have been raising this issue with clients for some time; the problem is that to a large extent we do not know precisely what effect the new regulations will have and how they will work in practice.

There are, however, a number of points on which we can be relatively clear:

l The number of sites suitable for hazardous wastes will fall from about 250 to only 10 that are licensed.

l There are no licensed hazardous waste sites in Wales or the West Midlands and only one in the south east, where over 1Mt of hazardous waste is generated each year, largely as a result of brownfield development.

l Landfill costs are set to increase by three or four times, coupled with increased haulage costs. For example, the closest site to Dover will probably be in Cheltenham.

l The cost of investigation and testing will increase.Costs for the leaching tests are expected to be about £150, with 10- to 15-day turnarounds likely. It is, however, questionable whether labs will be able to cope with the influx of samples arriving on 17 July.

Some areas remain very unclear, such as what constitutes pre-treatment of hazardous waste and how many tests will be required on a given site to meet the WAC. Also, to what extent does Defra's ongoing review of the waste licensing regime allow new process-based remediation technologies to fill the void left by landfill?

In the short term, confusion is the most likely consequence of the new regulations and there is a strong chance that many small sites, or large sites that are heavily contaminated, will become unprofitable.

A number of remediation specialists and regulators believe that in the short term, remediation of many sites with hazardous soil contamination will be brought to a halt.

Large developers may be able to defer development of sites in the hope that more hazardous waste landfills will come on stream in the medium term.

Small and medium developers are likely to be badly affected, partly because they rely on cash flow from throughput of a relatively small number of developments and partly because they are unlikely to have anticipated the new regulations.

In the longer term, there is hope that the new regulations will at last achieve the government's desired aim of reducing our reliance on 'dig and dump' as a favoured remediation method.

A recent survey sponsored by the Department of Trade and Industry shows civil engineering techniques (mainly disposal to landfill) were used in 90% of cases of land remediation.

Reinforcing concerns with regard to small developers, the survey found 63% of remediated sites were less than 1ha and 63% of the cases involved residential development.

For a typical small housing development of six houses with modest gardens, it has hitherto been too easy for the developer to be advised to remove contaminated soil. Often as much as a 1m thickness is removed and taken to landfill.

Such decisions were probably made on the basis of poor advice, a desire to save money on site investigation, an aversion to risk or just common practice. But at a total cost of perhaps £6,000 for disposal, it was not a painfully bad decision.

If this cost increases to £20,000 or £25,000, the developer will be driven to seek better advice, leading to better decisions and aided by more readily-available process-based remediation technologies as an alternative to dig and dump.

Assessment of risks to human health and groundwater at contaminated sites have become commonplace. Faced with rising landfill costs, it is to be hoped that practitioners and regulators will embrace risk assessments as an integral part of an overall cost-effective remedial and waste management strategy for site development.

If remediation specialists are at least able to take up some of the slack created by the reduction in landfill capacity, there is an opportunity for process-based remedial methods. Insitu and exsitu treatment or site containment may then become cheaper choices than landfilling for hazardous wastes.

Maybe not immediately, but certainly in the medium term, developers should start to factor in the time such methods may add to their development programmes and see them as the norm, with landfilling as the costly exception.

Geotechnical and geoenvironmental engineers should find themselves in the favoured position of being sought out by clients facing a costly problem that they are well placed to resolve.

We should use the new regulations as another way of convincing clients of the benefits of properly specified site investigations and interpretation of the findings by a geotechnical or geoenvironmental engineer.

Steve Branch is managing director of Geotechnical & Environmental Associates.

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