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Back to the land: reclamation in China

Atkins | 21 Oct 2014 | Comments

China’s living standards and global economic standing have been on the rise for three decades, but that rapid industrial growth had an impact on the country’s environmental health, including extensive contamination of its arable land and of industrial areas. Today, efforts are being made to take that land back to its roots.

“[It] is hard to be optimistic about the state of soil nationwide” – thus read a statement published on the official website of China’s Ministry of Environmental Protection (MEP) early in 2014, alongside the results of its latest soil survey report. “Some regions are suffering from relatively heavy pollution, the quality of soil in planting areas is worrying, and the problem of waste from industry and mining also stands out.”

As with all successful industrialised nations, rapid growth in China has brought with it unintended consequences. This includes the contamination of large tracts of land due to factories producing electronic and industrial goods leaching heavy metals into soil, and chemical pollutants and fertilisers disrupting the local ecosystem. The resulting contaminated areas – estimates range up to around 200,000 individual sites – are not fit for human habitation or development.

According to the MEP’s study, 16.1 per cent of the soil samples and 19.4 per cent of its arable land showed contamination – 82.8 per cent of the contaminated samples contained toxic inorganic pollutants, including cadmium, mercury, arsenic, chromium and lead.

“Due to long periods of extensive industrial development and high pollutant emissions, some regions have suffered deteriorating land quality and serious soil pollution,” the MEP conceded. This contamination burden requires clean-up, or remediation, to bring the land back into safe, most beneficial use.

Yufeng Guo, technical director of water and environment for Atkins in China, is at the forefront of Atkins’ efforts to develop its remediation business in China, and it hasn’t been a simple process – “The market hasn’t really been open up until now,” he says.

Guo explains that, up to now, remediation work has largely been done by local Chinese companies, procured by the local government. However, he says, they didn’t always have the full range of skills and solutions. As a result, China continues to face a challenge in its efforts to reclaim and repair the land lost to industrial and agricultural pollution.

Cleaning up

What would a typical remediation project in China look like?

“It’s complex because the nature of the contamination may vary,” explains Guo. “It may stem from heavy metal or chemicals, or agricultural waste in the form of pesticides. There are all kinds of pollutants with different levels of impact on the soil, opening up different types of risks to public health and the environment.”

The first step in the process is a full survey of the affected land. It’s a process that Mathew Worboys, head of contaminated land and water with Atkins in the UK, knows all about, having led a team of around 100 reclamation professionals on a range of projects in the UK, including remediating the Queen Elizabeth Olympic Park site before the London 2012 Olympic Games. Atkins has been actively involved in the practice of regeneration of derelict and contaminated land into productive uses in UK and worldwide since the mid-1980s.

“First, we gather all the available historical data – often looking at old maps – and plans of the site, as well as the land form,” says Worboys. “Then we look at the geology – depending whether you have sand, clay or rock under a site, any contamination spillages that may have occurred could appear in different places or could have moved elsewhere. We conceptualise the site based on all available information, including having a look and walking over the area.”

Once on site, Worboys’ team will aim to identify the main areas where contamination might be focused: “For example, if petrol is stored in a tank on site, then we check whether there’s been any petrol spills around that area. We scale that up to things like a gasworks, oil refinery and whatever else the use might have been, to investigate potential sources. Based on our experience, we can then tell where the highest risk areas are and what might be involved in a clean up.”

The next phase, Worboys explains, involves an intrusive survey: holes are drilled, samples taken and soil or groundwater is analysed for chemical content in laboratory conditions, and so on.

“We gather that data and refine our conceptualisation of the site,” he says. “There are accepted environmental health and human health indicators about what levels of contamination are applicable under different land uses. We use these levels as a baseline, to emphasise why some results are considered unacceptable and to underline the fact that something needs to be done.”

Making right

Once the analysis is complete, Worboys’ team focuses on the physical, biological or chemical remediation of the site: “There are many different options and methods,” he says. “It depends on the client’s programme, cost considerations, technical issues and the carbon efficiency; for example, the environmental sustainability of digging up a whole site and disposing of any contaminated material elsewhere may be a simple solution, but is often not sustainable and can be expensive.”

The range of solutions includes the increasingly popular methods of bio-remediation –which involves digging out and cleaning the soil of its contaminants with the aid of microbes – and soil washing – where the soil is physically washed, spun and dried to remove contaminants. In both cases these can be done on the site and the soil returned to the ground.

That doesn’t mean the soil must be absolutely clean, it just needs to be fit-for-purpose. Will the site be used to construct residential properties, a children’s playground or an industrial complex? Will it be open to the public with no restrictions? Or largely housing warehouses or a car park? The answers to these will determine – in part – the type of and extent of the solutions being proposed.

”Whatever the remedy, the resulting land should be suitable for its use, and not present a risk to the environment and ecosystem,” says Worboys. “If it is to be a car park, you don’t necessarily have to remediate a site to the point where it could be used for housing with gardens or agriculture and planting.”

Time will tell

Of the many challenges, Yufeng Guo says one of the biggest hurdles facing developers and local authorities in China is the fact that successful remediation doesn’t happen overnight – indeed, the lifecycle of some projects can run to a decade or more.

“Finding the right remediation treatment takes time, not every approach will work,” he explains. “That uncertainty can be caused by several factors. For example, sometimes it isn’t possible to do a full survey and you’re limited to checking a grid that may have 50 or 100 metres between samples – it depends on the density of the boreholes. That affects your understanding of the soil being surveyed.

“We work closely with contractors to monitor whether the chosen solution is proving effective and we adjust things if necessary, in order to achieve the ideal treatment.”

Along with its technical experience, Atkins has a track record of helping authorities finance remediation projects – work that can be too costly for one municipality to bear on its own.

“Proper planning is really important on the project side and that’s where Atkins’ expertise lies,” says Guo. “Contamination and remediation work is costly and government funding to treat the contaminated soil is not limitless. There is a need for private funding and investment at the treatment stage. That involves putting together a clear and comprehensive plan to attract investment to help with the cost.”

There is no doubting the scale of the challenge facing China. The first steps have been taken, and these may be the first moves on what promises to be a long term effort to cleanse China’s contaminated lands. As the proverb says, “To get through the hardest journey, we need take only one step at a time – but we must keep on stepping.”

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