Talking filth and eating poison

Sustainability and environmental awareness are key considerations throughout all construction projects, especially at the feasibility and early design stages. There is little doubt that we would all wish every project to be sustainable and environment-friendly. However, there is also no doubt that if this were the case, it would cost a lot more to build things. Regardless of this, the government has made sustainability a policy objective, and the prime minster is to use his presidency of the G8 group of industrialised countries and the European Union to raise these issue worldwide.

Legislation has been put in place in the UK to reduce environmental impact and waste and this, combined with other legislative and planning procedures, means we must manage waste, embrace sustainability and carry out environmental design as cost effectively as possible.

One of the principal elements of this policy is planning guidance that encourages councils to concentrate their resources on urban regeneration through the redevelopment of brownfield sites. This article looks at what is generally the main problem with reusing these sites: the possibility that their soil is contaminated.

Much of the UK’s contaminated land is the legacy of previous industries, although ground contamination also arises from leaks, spills, poor waste disposal practices and discharges. The Environment Agency estimates that there are up to 300,000 ha of land affected by contamination, amounting to as many as 100,000 sites. Of these, between 5% and 20% are thought likely to be problem sites.

The traditional method of dealing with such sites has been to “dig and dump”, that is simply to remove the problem and put it into a landfill site. This practice is now legally restricted, and therefore remediation technologies are of fundamental importance to the viability of many schemes.

Strategies

The UK is one of Europe’s largest producers of hazardous waste, the output of which has doubled over the past decade. To reduce the reliance on landfilling as a means of waste disposal the EU Landfill Directive has been introduced, and since 16 July 2004, the

legislation has banned the disposal of hazardous and non hazardous waste within the same landfill cell. The legislation also requires hazardous wastes to be pre-treated to an approved standard prior to disposal.

The directive requires that landfills be licensed to accept either inert, non-hazardous or hazardous waste. From 16 July 2005, a testing regime will be required to determine the classification under waste acceptance criteria. The implementation of the directive has already resulted in a reduction of the number of hazardous waste landfill sites from 277 to seven. Digging and dumping is no longer a cost-effective solution on most projects.

Where a development requires soils to be removed from site, either to reduce the environmental risk or to allow earthworks to proceed, it is now necessary for the soils to be described using the European Waste Catalogue. Where soils are deemed to be hazardous it will be necessary to pre-treat the waste prior to any landfilling. This process does not have to occur on site, and it is likely that treatment centres will be developed where waste treatment, recycling and reuse will be carried out by licensed companies.

In areas of large-scale clean up, such as the Thomas Gateway, treatment centres known as hub sites are likely to be developed. Contaminated soils will be brought there from other sites, especially smaller ones where on-site treatment is not practical.

The soil would be cleaned and used as fill at other sites in the area.

This may appear to be the most cost-effective solution, but some issues have yet to be resolved, such as the definition of what counts as waste.

A likely by-product of the new legislation and an issue of widespread concern is the potential for an increase in illegal fly-tipping. Landowners should be careful to secure their sites to avoid becoming a solution for someone else’s problem.

Firms also need to be aware of their legal duty to ensure that their wastes are being disposed of lawfully and any companies offering cheap disposal should be treated with extreme caution.

For developers and owners of brownfield land, there will be further consequences. Developers may offer a lower price for brownfield sites, and site owners will face increased development costs and timescales due to the growing complexity of the legislative regime and the fact that on site remediation takes significantly longer than simply transporting your problem off site. It is likely that landowners will hold on to their brownfield land until they have

ways of developing them more economically, for example once hub sites and other intermediate treatment centres have been established, and are able to provide a more cost-effective option. In many respects the legislation is counter productive to the government’s vision of building more homes on brownfield land, at least in the short term.

In place of dig and dump, developers will need to consider new practices to mitigate the effect of landfill, such as:

• designing schemes so as to minimise the volume of waste material generated
• treating soils on site rather than removing them
• pre-treating contaminated soil to downgrade the classification from hazardous to non-hazardous waste.

The key to the development of a brownfield or contaminated site is increasingly going to be a thorough and robust site investigation and analysis, carried out or supported by a competent and experienced consultant. A detailed risk assessment based on this site investigation will enable all parties to understand fully the environmental risks to controlled waters and human health and will ensure that remediation and soil removal does not occur without a good reason.

In the short term, insitu remediation is more costly than transporting the soil, but as it becomes the prevalent and accepted approach and contractor competition and expertise develop, there will be an inevitable cost reduction.

Another consideration is that by putting site-based remediation technologies into the development programme, the sustainability credentials of the scheme will be improved and it will become more attractive to those granting planning permission.

To repeat: it is essential that any developer of a brownfield site undertakes an extensive site investigation undertaken to determine the nature of the contamination. The planning of the scheme can then complement the site remediation strategy, which will probably be largely site based.

Although remediation will be costly, costs can be mitigated by a risk management approach. The process may also be slower than in the past, but development will be more environment-friendly and more sustainable than the historical approach of digging and dumping.

Thirteen ways to clean up

1 dig and dump
Method The traditional approach, in which the contaminated soil is excavated, removed from site and sent to a landfill.

2 soil washing (in situ)
Method Soil is excavated, sifted to remove large objects, and then placed in a scrubbing unit where water and some detergents are added. The mixture is passed through sieves, mixing blades and water sprays that dissolve some pollutants and separate silt from the clay where most pollutants are concentrated.
Application Suited for large-grained soils such as sand and gravel
Contaminants eliminated Fuels, metals and pesticides

3 permeable reactive walls, barrier walls and capping
Method Barrier walls and capping are used to break the “source–pathway–receptor” chain. Impermeable barriers and caps are designed as a cut off, whereas a reactive barrier treats contaminated groundwater as it passes through.
Application They are often used where there is no possibility of economically removing the source of contamination, but a long-term solution is required to prevent the leaking of contaminated groundwater.

4 bioremediation (in situ and ex situ)
Method Microbes found naturally in the earth convert hydrocarbons into water and carbon monoxide. The right conditions must be present for the bacteria to multiply to a volume necessary to treat the contamination successfully. Soil must be at the right temperature and must contain sufficient nutrients and oxygen. In some cases additional oxygen and nutrients are pumped e e underground; in others the soil is dug up and the process takes place above ground, where the right conditions are easier to achieve. The method requires little equipment and exploits natural processes.
Contaminants eliminated Petrol and oil

5 soil vapour extraction (in situ)
Technology Vapours are formed when chemicals evaporate. If a vacuum is applied to the soil, the vapours can be pulled out, collected and treated. Sometimes vapour extraction is combined with air sparging (pumping air into the ground) to speed evaporation.
Application Remediation of petrol spills or around structures where excavation is not possible.
Contaminants eliminated Solvents and fuels.

6 thermal desorption (ex situ)
Technology Soil is excavated, dried and passed through a desorber (a large oven) where heat is used to remove harmful chemicals. These are turned into gases that can be collected using a vacuum system.
Application Dry, heavily polluted soils.
Contaminants eliminated Fuel, coal tar, solvents.

7 thermal treatment (in situ)
Technology Heating polluted soil to destroy chemicals or change them into gases. Heating is achieved using steam, hot air, hot water, electrical resistance (that is, passing an electric current through the soil to heat the groundwater to steam and evaporate chemicals), radio waves and thermal conduction using heated wells or a heated blanket on the surface.
Application One of few ways to destroy NAPLs (non-aqueous phase liquids – organic liquids with a low solubility in water). Works well with clays.
Contaminants eliminated Fuels and chlorinated solvents, NAPLs.

It is likely that landowners will hold on to their brownfield land until hub sites have been established

8 electrokinetics (in situ)
Technology A low-voltage direct current is used to treat metal contaminants. Positively charged metal ions migrate toward the cathode from where they can be pumped to the surface and treated.
Application Where metal contaminants occur below the water table.
Contaminants eliminated Metals.

9 fracturing
Technology This is not really a treatment in itself, but fracturing is used to break up dense ground as part of other clean-up methods. The cracks create paths through which harmful chemicals can be removed and treated. Fractures can be created by forcing liquid or air into the ground, or by means of explosives.
Application Dense, compact ground or rock

10 chemical oxidation (in situ)
Technology Contaminants’ states are altered by the application of oxidants to the soil. This method can convert pesticides and fuels into water and carbon dioxide. A number of oxidants may be used, including potassium permanganate, ozone and hydrogen peroxide. Concerns have been raised that the technique merely adds further toxic chemicals to the land, but they dissipate quickly.
Application Sites where pollution is buried too deep for other methods to be used.
Contaminants eliminated Pesticides, solvents and fuels.

11 soil flushing
Technology By pumping chemicals or water into the ground, harmful chemicals can be flushed out. The chemicals are then pumped to the surface through wells, where they are treated. Some chemicals, such as solvents and heating oil, do not dissolve readily in water – instead, surfactants (like washing-up liquid) and solvents (like alcohol) are mixed with the water and pumped down wells to help dissolve the chemicals.
Application Works best in permeable soils, particularly if a layer beneath the polluted stratum is made of an impermeable material such as clay.
Contaminants eliminated Solvents and heating oils.

12 solvent extraction (ex situ)
Technology Excavated soil is mixed with a solvent in a plant called an extractor. The solvent dissolves the chemicals and is then transferred to a separator, where the chemicals are removed. The solvent can then be reused.
Application For chemicals that do not dissolve in water
Contaminants eliminated Oil, grease and polychlorinated biphenyls (PCBs).

13 stabilisation (in situ and ex situ)
Technology Contaminants can be locked into the soil by mixing in fly ash, cement or lime. These form a stable, solid mass resistant to weathering.
Application Soils with a high clay content.
Contaminants eliminated Heavy metals.

Where you win and lose on tax

Tax relief for remediation of contaminated land

The Finance Act 2001 introduced legislation providing tax relief on land remediation costs in the UK.

Who can claim?

The tax relief is available to a company that has acquired a property for the purposes of its trade or for a rental business.

The following types of company qualify for relief:

• Property investor
• Property trader
• Companies that occupy property in the course of their trade

Taxpayers other than companies are excluded, and relief cannot be claimed by the company, or by any connected party, that has caused the contamination.

The benefits

The relief is given in the form of a tax deduction equal to 150% of the land remediation expenditure incurred in an accounting period.

Example 1 So, if a company spent £100,000 it could reduce its tax liability by up to £45,000 (£100,000 × 150% × 30% for corporation tax).

However, in the event that a company cannot obtain immediate benefit because it is not in a tax paying position, it can surrender losses to the Revenue in exchange for a cash payment. The payment is called a land remediation tax credit and is equal to 16% of the losses surrendered.

Example 2 By this route a company could receive a cash payment of up to £24,000 (£100,000 × 150% × 16%).

Qualifying expenditure

Relief is given for “qualifying land remediation expenditure,” which comprises capital expenditure that would not otherwise qualify for tax relief and where tax relief has not been claimed previously.

Expenditure qualifying for any form of capital allowance is specifically excluded.

To qualify for relief under the legislation, the expenditure must:

• Be on land that is contaminated at the time of acquisition.
• Be for relevant remediation work, that is minimising the impact of pollution or restoring land.
• Be on eligible employee costs or materials incurred by the company or an amount paid to a subcontractor.
• Have been incurred because the land was contaminated (this excludes usual site preparation).
• Must not be subsidised.

Claiming relief

Relief can only be claimed if an election is made, in writing and in the tax return, within two years of the end of the accounting period and the expenditure is deductible for that period.

The tax repayment or the surrender of losses will not be paid over unless the taxpayer’s affairs are up to date. The cash received as a land reclamation credit is not income subject to taxation.

Claiming this relief will mean that a further tax deduction will not be possible when calculating the capital gains position on disposal of the asset.

Landfill tax

The landfill tax was introduced on 1 October 1996 with the aim of deterring the landfilling of waste and to encourage reuse, recycling and other methods of waste management. The tax is levied on licensed landfill site operators and is passed on to clients by means of increased costs, thereby satisfying the polluter pays principle.

The tax is charged at two rates. The lower rate of £2 a tonne applies to inert waste such as sand, gravel, stone, topsoil, bricks, reinforced concrete and the like. The standard rate applies to all other waste, and is set at £15 per tonne for the year commencing 1 April 2004. This will rise to £18 per tonne this year.

From 1 April 2006, the rate for active waste will rise by at least £3 a tonne on the way to a medium-to-long-term rate of £35 a tonne.

Where historically contaminated sites are being cleared to facilitate development an exemption from landfill tax may be obtained if certain conditions are satisfied. An important point to note is that an exemption must be secured before any waste is removed to landfill, as it cannot be granted retrospectively.