Leachate (contaminated water) from an old landfill was polluting the river Ely and Cardiff Bay due to a lack of knowledge about how to manage the site.

The giant landfill at Ferry Road in Grangetown closed in 1994 and is now the site of a park and a shopping centre.

Leachate from the landfill—water mixed with chemicals from decomposing rubbish—was meant to be pumped out of the tip to stop it from leaking into the river and the Bay.

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But inspectors found a pumping station at the landfill was not functioning properly, and staff responsible for managing the site didn’t know what the pumping station was supposed to do.

Regulators warned Cardiff Council there was a significant non-compliance of their permit, meaning a potential to have a significant impact on the environment or people. 

Natural Resources Wales urged the council to “operate the leachate collection system to its purpose to completely stop leachate entering into the surrounding environment”.

After receiving reports of leachate entering Cardiff Bay, inspectors visited the landfill site twice with engineering experts and Matthew Wakelam, the council’s assistant director of street scene.

Details of problems at the landfill—including “poor knowledge” of how to manage it—were published by Natural Resources Wales in a compliance assesment report.

The inspectors found that a pumping system was faulty, so leachate was accumulating in the landfill and escaping through an old pipeline, which should have been decommissioned. They also saw leachate escaping through a new pipeline into the river Ely. According to Natural Resources Wales, the council didn’t even know what the pumping system was for.

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In the report, the inspectors said: “Cardiff Council informed us, at the inspection, that they were not aware of the purpose of this pumping station before our visit. In our second visit, we observed that the council was able to operate the pumping station manually, until the system could be operated automatically.”

Another issue was a lack of key documents. Instructions on how to monitor and manage the landfill were missing, as well as a plan on how to protect the surrounding environment from pollution.

The inspectors said: “The operator does not have the necessary knowledge and information to operate and monitor the site in accordance with the permit, and has not been operating and monitoring the site in accordance with the permit”.

About four million cubic metres of rubbish was dumped at the landfill before it closed, which is now the site of Grangemoor Park and Cardiff Bay Retail Park. Regulators are still reviewing the operations at the site, to ensure any further pollution into the river Ely or Cardiff Bay is prevented. The pumping station is now operating automatically, and is regularly monitored.

In a statement, Fiona Abbott, operations manager for Natural Resources Wales, said: “In March 2021, we undertook an inspection of the closed Ferry Road landfill alongside the operator Cardiff Council.

“During the inspection we identified a number of permit non-compliances relating to the operation of the landfill, in particular the landfill leachate management system, which resulted in discharges to the river Ely and Cardiff Bay.

“We have been in discussion with Cardiff Council to ensure that the necessary works are undertaken so that the landfill is operated as designed and leachate managed correctly. We are continuing to review the operations, to ensure the conditions set out in the permit to protect people and the environment are complied with.”

Cardiff Council said it was refurbishing its systems to manage leachate, which is sent to be treated at sewage works. Staff have not observed any further discharges since work was done on the pumping system.

A council spokesperson said: “The local authority has undertaken, and continues to undertake, considerable works to refurbish and upgrade the existing leachate management systems. This is reducing the volume of leachate within the decommissioned landfill, directing it to the site’s leachate treatment plants, prior to being transported for further treatment at a sewage works.

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“Since works were undertaken to the pumping system, in order to reduce the leachate level in that area, no further emission has been observed. Cardiff Council has significantly increased environmental monitoring and sampling at the site, and works closely with Natural Resources Wales to ensure stringent controls and monitoring arrangements are in place.

“Monthly samples are being taken across the site, and at all surface water discharge points, including upstream and downstream, and at the Watermark building outfall. Sampling has not indicated any landfill leachate pollution. Further to the considerable measures taken by the council to protect the local environment, a specialist consultant has been commissioned to produce a hydrogeological risk assessment for the site.”

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