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Contamination proves an education

When Frankis Solutions took on a disused pharmaceutical site in Kent, the company found more asbestos than it had bargained for.

But Frankis turned this into an opportunity to enhance its skills in this area without affecting the build programme.

The site was a 14 hectare former pharmaceuticals manufacturing facility, which is being redeveloped for residential and commercial use.

“The site was significantly contaminated,” says Frankis Solutions business development director Paul Dalrymple.

“Essential Lend, the client, was particularly risk-adverse and they didn’t want to inherit any future liabilities, so we took on the entire package as a design and build, lump-sum, all-risk contract,” he says.

Although this contract type was not unique for the company, Mr Dalrymple explains that is was “a bold step” and Frankis employed an independent consultant to ensure both the client and the company were happy with the terms of the contract.

Following several months of contract negotiation, all parties were agreed and work began onsite.

Frankis supervised the demolition, which was sublet by the client, before beginning on the decontamination and remediation works.

Challenging reality

“We had a site investigation report that demonstrated that arsenic was present but it seemed to show it was quite shallow,” says Mr Dalrymple.

“But in reality when we started digging and treating the shallow arsenic, we were chasing it deeper and deeper.

“We found it was at about double the depth we had anticipated, and arsenic is quite difficult to treat when the numbers are high.”

The site contamination was treated with a combination of in situ treatment and ex situ bioremediation, while some of the materials needed to be disposed offsite.

“We ended up putting in extensive temporary works infrastructure to enable excavation of a significant volume of unexpected arsenic at depth,” explains Mr Dalrymple.

“The onsite treated material was able to be reused and built back into the works. The contamination, combined with the complex geology and a chalk aquifer lower down, meant it was quite a challenge to make sure we didn’t create a pathway to the lower aquifer and contaminate it.”

The unexpected levels of contamination also caused concerns for a river and pond on the site. “The River Darent runs through the lower part of the site; potentially it was a very sensitive receptor and became an obvious focus for the regulators,” says Mr Dalrymple.

“Given some of the higher levels of contamination that were discovered that weren’t evident in the site investigation, they asked us to introduce a barrier to the lower site to protect the river and the groundwater. This was another late design and build requirement that we absorbed into the programme and into the budget.”

Determined approach

Despite these difficulties, Frankis was determined not to let the unforeseen arsenic affect the build time or budget.

“The arsenic was a challenge, as the level of contamination was completely unexpected; the potential impact on both the programme and the commercial side meant the pressure was on for us to perform,” says Mr Dalrymple.

“We had signed up to a build programme and this was an unforeseen extra, but we delivered it on time and budget, which emphasised our commitment.”

The difficulties also meant the team at Frankis enhanced their knowledge of treating arsenic contaminated ground, which will help them when tendering for work in the future.

“This process further educated our team and we gained more knowledge of stabilisation processes, as the arsenic was quite heavy in some places. We’ve carried that forward, which will help us win work in the future,” says Mr Dalrymple.

This project was one of the most complex Frankis has worked on, but the site is now fit for purpose and can be used to create the mixed-use commercial and residential development.

“What we’ve done is hand over a validated, signed-off piece of land that the client is happy with and hopefully the developers will have a much easier follow-on packages because the contamination issues have been addressed, with all the abnormalities gone,” says Mr Dalrymple.

The company is also hoping it’s commitment to deliver on time and on budget has put it in the running for further work on the site.

“We’ve put ourselves in a strong position to negotiate a follow-on enabling works package, which is roads and sewers,” says Mr Dalrymple. “It’s a large site and our performance has got us into a position where we’re hoping to do some more work.”

 

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