June 28, 2014 12:01 am

How a polluted oil plant in Wales became a model housing project

Coed Darcy village is more ambitious than The Prince of Wales’s scheme at Poundbury – and has international significance
The demonstration village at Coed Darcy, overlooking the recently restored Crymlyn bog©Simon Bevan

The demonstration village at Coed Darcy, overlooking the recently restored Crymlyn bog (Photograph: Simon Bevan)

The Prince of Wales enjoys the odd high-profile intervention when it comes to the built environment. Headlines don’t always tell the whole story, but who else gets a scoop about architecture screaming across the red tops? And yet, the more interesting stories are sometimes found in the most unexpected places, where the narrative is different from the Made in Chelsea tales of aristocratic power games.

It is a story of dull, unglamorous, dogged hard work: of The Prince (or rather, his colleagues and employees, representing his various charitable trusts and foundations) pursuing his ambitions from surprisingly deep in the trenches. And the results have the potential to fail – or to become game changers.

In south Wales, near Swansea, The Prince’s ideas are being put into place on a giant scale. The Llandarcy oil refinery was founded after the first world war, when Winston Churchill, then minister for munitions, realised the strategic national importance of being able to refine crude oil on home territory. During more than 60 years of industrial production, Llandarcy rose, under the auspices of oil group BP, to become one of the largest employers in Wales. By the time the plant started to shut down in the mid-1980s, however, it had also become one of the most polluted sites in Europe.

Llandarcy oil refinery in the 1960s©BP

Llandarcy oil refinery in the 1960s (Photograph: BP)

In a world of post-industrial decline, there is a tendency for a desecrated landscape to be replaced by further desecration; a world of arterial ring-roads leading nowhere, of service stations, shipping warehouses and cheap big-box retail, of unemployment and abandoned communities. It is a scenario that The Prince has struggled to fight across Britain. Visiting this part of Wales about 20 years ago, he feared it might be happening again, and began a quiet engagement – which led, ultimately, to a far-sighted decision by BP to invest in a huge clean-up operation, and to create new jobs and housing infrastructure based on the model established by The Prince’s development at Poundbury in Dorset. Here, the scale is infinitely more complex, and the challenges of reclaiming brownfield industrial land far harder: the lessons of this latest project will have an international significance.

The lessons of this latest project will have an international significance

The vision is for a pair of linked, mixed-use “urban villages”, with differing characters: one intentionally quieter and more rural in outlook; the other more urban in scale and use, with a new town square, three schools, multiple shops, commercial spaces and local employment – there will be 4,000 houses in total. The second phase of 300 homes, built by Persimmon, is on site and selling well, with 72 properties occupied and a further 25 reserved since early 2013. Coed Darcy, as the new town has been christened, is beginning to move fast. A site was selected to build a small number of houses to demonstrate the quality that will be sought on the project as a whole. My company was selected to design these buildings, drawing inspiration from the simple local vernacular of southwest Wales and the Brecon Beacons.

CGI of how the 1,060-acre site will look in 20 years©Ian Yallop

CGI of how the 1,060-acre site will look in 20 years (Photograph: Ian Yallop)

The Prince continues to have personal involvement, visiting Coed Darcy on an annual basis and chairing regular meetings to understand issues and progress, both at Clarence House and at Llwynywermod, his Welsh farmhouse. Yet it is the continuing involvement of his Foundation for Building Community, and its associated network of engineering and architectural practices, that achieves impact on the ground.

Ben Pentreath inside a village home he designed at Coed Darcy©Simon Bevan

Ben Pentreath inside a village home he designed at Coed Darcy (Photograph: Simon Bevan)

A short distance up the coast towards Swansea, on brownfield land also formerly owned by BP and now being developed by St Modwen, the foundation is working with Porphyrios Associates and Hopkinson on the delivery of the new Bay Campus for Swansea University. The combined schemes are projected to generate a local economic impact of £3bn over the next decade. The power of The Prince’s vision should not be underestimated.

The Prince is an aesthete; we know that he worries about the detailing of a door handle or glazing bar as much as the grander sweep of industrial decline and renewal. Walking around Coed Darcy, therefore, cannot be entirely without pain. The reality of a world where volume housebuilding meets the prescribed, particular world of the Poundbury aesthetic is a complicated place; the subtleties of the traditional Welsh towns are not easily integrated into the factory-production construction methods employed by Persimmon. I cannot help wondering if the end results would be more convincing, ironically, if the architecture tried less hard.

The demonstration village©Simon Bevan

The demonstration village (Photograph: Simon Bevan)

A year ago, I walked around the site with Alan Francis, the town architect (a role established by the local authority, St Modwens and the foundation to ensure architectural integrity) whose passionate state of worry about the quality of architectural detailing would have made The Prince proud. He need not fear. The finer points of architecture are not the battleground here. The challenges are far bigger, and it is early days – but the solutions appear resolutely to be working.

In 2008, Ben Pentreath designed the demonstration village at Coed Darcy, a group of eight houses completed by St Modwen in 2013. They showcase sustainable construction methods and will form the edge of the village

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The nitty-gritty of one of Europe’s biggest remediation projects

When BP’s Llandarcy oil refinery in south Wales finally closed in 1998, its legacy included 1,060 acres of land heavily polluted with the by-products of 80 years of processing hydrocarbons under environmental standards far lower than those in force today, writes Clive Cookson.

The clean-up began when St Modwen, a property group specialising in brownfield developments, bought the renamed Coed Darcy site in 2008 – and three years later one of Europe’s biggest remediation projects was finished and the construction phase could begin.

View across the hallway into the kitchen of one of the village homes©Simon Bevan

View across the hallway into the kitchen of one of the village homes (Photograph: Simon Brevan)

The clean-up figures are impressive. More than 1.1m litres of oil, recovered from lakes, ponds and soil, were recycled for use as fuel and lubricants. In addition, 200,000 tonnes of sludge was cleaned up, employing new remediation technologies to produce material usable for landscaping. A further 200,000 tonnes of concrete, and 100km of pipeline and cables, were also removed and recycled.

Neil Williams, St Modwen’s remediation chief, says fortunate timing enabled the team to complete the job ahead of schedule. “We were getting going just as the remediation of the Olympics site in London was finishing in 2008/09,” he says. “That allowed us to procure contractors and equipment more readily than would normally have been the case.”

Several companies provided their services, including Celtic, Hydrock and Hawk, while WS Atkins acted as engineering consultants. The whole operation, which cost more than £50m, was monitored closely by BP.

More than 1.1m litres of oil, recovered from lakes, ponds and soil, were recycled for use as fuel and lubricants

“The refinery’s legacy was important for BP, so it needed to know it was being managed responsibly after disposal,” says Williams. While Llandarcy was relatively free of the highly toxic compounds that face people cleaning up some chemical plants, it was heavily contaminated with filth – hydrocarbon wastes are wholly incompatible with residential and commercial development. Various techniques were used to treat the different types of oily residue. Heavy oils that had sunk to the bottom of ponds and lagoons, forming a deep layer of sludge, received a dewatering treatment new to the UK. A specialist dredging team pumped 60,000 cubic metres of oily sludge up into Geotubes – huge floppy cylinders developed in the Netherlands.

The sitting room of a home by Ben Pentreath©Simon Bevan

The sitting room of a home by Ben Pentreath (Photograph: Simon Bevan)

The Geotubes’ special fabric enabled most of the water to drain out of the sludge. This left a more concentrated material with a consistency like peat, to which the team added “cement bypass dust”, a waste product of cement manufacturing. The outcome was a structural solid used to build road embankments for Coed Darcy, without having to bring in construction materials.

Lighter hydrocarbons – sitting atop open ponds, reservoirs and shallow groundwater – were easier to handle. They could be removed with specialist mops for recycling into oil products.

Earth that was less heavily contaminated but still in need of cleaning was subject to bioremediation, where natural soil bacteria broke down the hydrocarbons into carbon dioxide and water. To introduce the oxygen needed for this process, the team ploughed up the ground, forming windrows (rows of earth) that could be aerated further by turning them over every two or three weeks.

One aim of the remediation has been to keep the movement of waste in and out of the site to a minimum by reusing as much as possible at Coed Darcy. “With landfill tax at £72 a tonne we wanted to retain all our waste on site,” says Williams.

In spite of all the past century’s industrial activity, Llandarcy retained some rich wildlife on its doorstep – notably Crymlyn Bog and Pant y Sais National Nature Reserve, the largest surviving lowland fen in Wales. This internationally important wetland will provide a natural source of native plants and animals to spread back across the site. According to Natural Resources Wales, Coed Darcy already hosts the largest population of great crested newts in Wales.

Greater crested newt at Coed Darcy©Simon Bevan

Greater crested newt at Coed Darcy

The developers are also giving wildlife some extra help, beyond the general “green-up”. They have built a bat house to welcome species such as the pipistrelle and brown long-eared bats, which were displaced from the redundant BP buildings. Badger setts have been created and unusual birds are being encouraged to nest.

Williams cannot disguise the pride in his voice when he says: “We have turned this site from a black place into a lovely, green environment.”

Clive Cookson is the FT’s science editor

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