MWH Manywells
Work continues on award-
winning Manywells land
remediation project
The Manywells project to make safe and landscape the Contaminated Land Capital Programme,
Cullingworth landfill site is nearing its final phase. And the
with a commitment to continuing funding
award winning Yorkshire project now has a lot of success
to ensure the work is completed.
In May 2007, MWH won the three year
to report.
contract to provide technical support to
the existing Bradford Council engineering
team against six other consultants. The
first priority was to understand the nature
of the site, then establish what was
happening within the body of the landfill,
trace the pollutant linkages and drain
water from the waste.
Adrian Parker, MWH’s project
manager, explained: “The site had been
significantly over-tipped by the previous
operator and had been left uncapped.
There were also impermeable layers
within the waste, reducing drainage. As
a result, there was a saturated mass
of domestic, commercial and industrial
waste that wasn’t breaking down due to
the wet conditions. In addition, leachate
and landfill gas was leaking from the
sides of the landfill in some locations.
Although landfill gas was being collected
I
t is two years since environmental As the land had reverted to Crown from the site, its composition and limited
engineering and water consultants ownership, following the private quantity prevented burning of the gas.
MWH started work with the City of company’s demise, it fell to Bradford Considerable investigation, data collection
Bradford Metropolitan District Council Council, working with the Environment and analysis were needed to understand
and their combined successes include Agency, to make the site safe. what was going on underground.
negating the need to remove surplus “Through excavating targeted deep
waste, progress on returning the site to Site ‘determination’ holes, promoting drainage and temporarily
nature, and a national award for engaging Kate Gabriel, principal environmental capping part of the site, it was anticipated
with local stakeholders. health manager with the Council, that the decay process could be started,
The Manywells site was a former explained: “The primary reason for the promoting settlement of the site. In
sandstone quarry, excavated from 1852 Council’s involvement in the site was addition, the drainage of water from
until the 1970s. When quarrying ended the determination of the site as being higher parts of the site would greatly
in the 1970s the site was turned over to contaminated within the meaning of Part reduce the seepage from the sides of
landfill use by a private firm. In 2001, as IIA of the Environmental Protection Act the landfill. As a temporary measure land
the site reached the end of its landfill life, 1990. There were risks from what are drains were installed to collect the bulk of
the contractor went into receivership. known as significant pollutant linkages, the escaping leachate.”
The company’s receivership occurred from the migration of landfill gas and
before the site had been properly capped leachate from the site.” Community involvement
and landscaped, leaving the problem of The decision to determine the site, in As part of the management regime to
remediation to the local authority and early 2003, came after consultation with prevent weather damage, the temporary
nearby community. Worse still, along with the Environment Agency. Other extensive clay cap was hydroseeded. This is a
the unsightly legacy of years of landfill, surveys of the site were undertaken, until process where grass and wildflower
there were concerns that polluted water an outline solution involving the removal seeds, mixed with water slurry containing
was seeping into the surrounding land of a considerable amount of waste was fertiliser, soil binder and mulch, were
and that landfill gas was escaping from agreed with the EA and Defra in 2004. sprayed on the site to encourage plant
the site. Defra is supporting remediation from its growth and coverage. The site was made
14 | Impact • February/March 2010
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