Works taking place at historic Sunderland gas plant to prevent toxic tar leaking into waterways
Vital repair works at a historic gas site in Sunderland are taking place to prevent “substantial volumes” of toxic coal tar leaking into groundwater from which it could potentially infiltrate into our waterways.
The discovery of the nine metre deep former gasholder tank was made by experts from Northern Gas Networks who were carrying out investigations at the now closed gasworks site in Sunderland, which is within sight of the North Sea.
A Northern Gas spokesperson said: “After extensive investigations, experts from Northern Gas Networks discovered that a nine-metre deep former gasholder tank present beneath the site contained substantial volumes of toxic coal tar – a common by-product of gas manufacturing before natural gas was introduced in the 1960s.
“The tank is well beyond its design life and at risk of structural degradation which could have led to leaks into the groundwater below.”
Northern Gas Networks, who deliver gas to 2.9 million homes and businesses across the North East, northern Cumbria and Yorkshire, have this week confirmed that remediation work has been taking place to remove the toxic tar from the container before any potential leaks occur.
Specialist contractors Rhodar joined forces with subcontractors, environmental engineers Geo2, to carry out the work.
Together, they’ve designed and installed a bespoke solar-powered pumping system that extracts the coal tar from the tank – a sustainable alternative to traditional generators.
The tar is then stored in secure containers before being safely transported to a licensed disposal facility.
Tom Keighley, Land Remediation Manager at Northern Gas Networks, said: “We want to leave a positive legacy at all of our sites, which is what our land remediation projects are all about.
“We take a proactive approach which involves investigating these sites before problems occur. This means we protect the local environment, greatly reduce the risk of future contamination and meet our obligations to the industry regulator Ofgem with confidence.
“Wherever possible, we aim to implement solutions that are innovative and sustainable, hence our use of solar power rather than traditional fuel powered generators to operate the pumps.”
The company said the work is due to last until around December (2025) with no disruption to the local residents or environment.
Northern Gas Networks has undertaken similar projects including in Newcastle where similar solar powered pumps were use to remove more than 6000 litres of toxic coal tar from an underground tank which dated back to the Victorian era.
Following the successful removal of the toxic tar Northern Gas Networks received the Brownfield Briefing Award in 2018 for ‘Best In Situ Treatment’.
The award recognises projects which “champion innovation, sustainability, stakeholder collaboration and best industry practice on brownfield sites”.
Northern Gas Networks’ comprehensive land remediation programme works on sites where historical contamination has the potential to negatively impact the environment.