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From a hole in the ground to natural beauty on the coast

In the UK, it is the construction sector that generates the most amount of waste.

Figures from Defra suggest that more than 100 million tonnes are produced each year from construction, demolition and excavation (CD&E) activity. Disappointingly, around half of this material will not be recycled or reused and will instead be sent to landfill.

Innovation Strap

More alarmingly, Defra’s recently published report, Digest of Waste and Resource, states that, in 2014, the CD&E sector was found to be responsible for around 50,000 fly-tipping incidents, up by almost 20% on the year.

While the Government sets long-term, ecofriendly targets for the UK in its effort to move towards a zero-waste economy, the worldwide construction sector is expected to grow by around 70% during the next decade. With this in mind, there is now an increased level of pressure on developers and planners to source inventive and environmentally friendly methods of waste disposal.

One group of British developers is leading from the front. The team behind Crossrail, responsible for carrying out Europe’s largest construction project, has been able to set a positive example for the industry through its innovative use of cutting-edge science.

As the number of inhabitants in London reaches 8.6 million, the capital now has a population density of 5,491 people per square kilometre, putting a huge amount of pressure on transport networks. In order to cope with the increasing population, the Crossrail project will create more than 26 miles of subterranean tunnels, as well as nine new stations by 2018.

A construction project operating on such a great scale generates an enormous amount of waste. In fact, excavation work has already unearthed around six million tonnes of waste spoil as a by-product. The challenge is how to dispose of this vast amount of material in an environmentally responsible manner.

So ESG, which provides testing inspection and compliance services, was brought in to contribute to the assessment of the potential toxic risks that would come from reintroducing the waste back into the environment, and to ensure the soil was suitable for use in future land redevelopment schemes.

To help with the tunnelling process, the ground had been injected with polymers to condition the earth before its excavation by tunnel-boring machines. ESG developed methods of determining the concentration of polymers within the excavated soil following biodegradation, and the potential for them to leach into the surrounding environment.

Next, in order to pass strict environmental controls, the soil had to be tested for key chemical parameters such as asbestos, cyanide, aromatic hydrocarbons, arsenic and cadmium. If significant amounts of certain contaminants were present, they could result in environmental issues for the intended location, such as toxicity, carcinogenicity, polluted water or stunted plant growth.

Following the completion of ESG’s analytical activity, and then a robust assessment, the excess Crossrail spoil was declared legally compliant and safe for reintroduction into the environment.

Around two million tonnes of waste was shipped to Essex to help create a ground-breaking conservation scheme in conjunction with the Royal Society for the Protection of Birds (RSPB). The spoil was deposited at the Wallasea Island Wildlife Coast Project, which provides a sanctuary for a wide range of important wildlife and a place of natural beauty on the UK’s east coast.

Wallasea Island Wildlife Coast Project

Wallasea Island has been created to re-form the ancient wetland landscape of mud flats, salt marsh, lagoons and pastures, and provides a natural flood barrier along the coast. By contributing to the innovative conservation scheme, the Crossrail team is helping the UK in its effort to combat the effects of rising sea levels and a changing climate.

The RSPB intends to complete the Wallasea Island Wild Coast Project in the next 10 years. But to do this it needs another eight million tonnes of clean soils, preferably recycled from other large-scale construction projects. 

Amy Parekh-Pross is technical marketing manager of multi-sector services at ESG

A more responsible sector

The UK construction sector currently generates around four times the amount of waste produced by all British households combined. As the Government sees its Infrastructure Bill become law, the sector is expected to grow rapidly in the next few years.

Considering this, developers within the industry now have an increased level of responsibility to ensure that their projects not only benefit the country economically but also help the UK meet its long-term eco-targets and create a sustainable, environmental legacy.  

 

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