Minewater Treatment
What is so special about Horden?
Joseph Shipperbottom our environmental scientist, has been studying a masters in Hydrogeology at Newcastle University. With #groundwaterweek drawing to a close we thought we would share his learnings on the magical world of minewater treatment; after all, water quality is becoming ever more important.
Along with his Newcastle University cohort, Joe recently visited Horden in Country Durham, with the Coal Authority and Severn Trent.
Great, but what’s so special about Horden?
Coal mining in the Durham Coalfield came to an end in the early 1990s closing the colliery at Horden. Following the closure, the pumping equipment used to control water within the mine were turned off. As the rising water came into contact with the exposed mine workings, iron-rich minerals present in the rocks reacted with the water, releasing the iron into the water. The mine water also contains high levels of dissolved salts, with chloride concentrations around twice that of sea water. If the rising mine water in this area had been allowed to continue in an uncontrolled manner it would have resulted in the pollution of a regionally important aquifer.
How was it solved?
A passive treatment system was installed, where water is pumped from the former colliery shaft over an aeration cascade to increase oxygen in the polluted water, encouraging iron to precipitate out. Two settlement lagoons are used to settle the iron precipitate, which is later removed. The final section of the passive system uses iron-tolerant reed species to remove finer iron particulates. The treated water is then discharged to the North Sea.
So, what’s the learning?
This passive treatment option is a great low-energy, long-term solution to treating iron-rich polluted groundwater. However, it’s not applicable to all heavy-metal contaminated groundwater. What is important is that water quality sampling must occur prior to treated water being discharged and that’s one of the areas where we come in.
Envireau Water has extensive experience in water treatment, discharge and establishing monitoring regimes. Whatever the scope and budget we can provide the right solution. Get in touch to discuss a project on 01332 871 870 or info@envireauwater.co.uk.
