'Staggering' clean-up of river polluted by metal mine

A pilot scheme to clean rivers polluted by abandoned metal mines has delivered "staggering" results, environment officials have claimed.

The new technology - thought to be a world-first - removed up to 99.5% of metals which impact water quality.

The electrochemical technique separated a metallic sludge from mine discharges leaving clean water behind.

Natural Resources Wales (NRW) said it marked a potential "step change" in how the problem is handled.

Metal mining in the UK peaked in the 18th and 19th Centuries and though they have now all closed, their effect on the environment is still obvious.

Wales has more than 1,300 abandoned metal mines, impacting more than 67 water bodies and in excess of 370 miles (600km) of river.

Nine of the 10 worst affected catchments in the UK are in Wales.

The innovative treatment plant has been tested on a stretch of the river Rheidol near Aberystwyth in Ceredigion.

The area is popular with tourists for its scenic reservoir, steam train and red kites, but it was once home to mines producing lead and zinc which now discharge highly acidic, orange water into the river.

It is thought eight tonnes of metal, including zinc, chromium and cadmium, enter the Rheidol every year, spreading out over 11 miles (18km) of river, killing fish and other wildlife.

Since the 1960s the polluted water has been collected in large pools in an attempt to filter out the metals, with limited success.

More recently, treating it using a combination of compost, limestone and cockle shells has been more effective.

However, scaling up this technique would require much more land than is available in the narrow, steep-sided valley, so NRW asked technology companies to come up with an innovative solution.

"When we've filtered the samples we've been getting 99.5% removal of metals, which is quite staggering," Mr Stanley said.

"I don't know how much more excited I could be in relation to the results that have been shown here - it gives us a new tool in our armour to effect treatment at metal mines, particularly those in steep, challenging environments like this."

Swansea-based firm Power and Water has been granted a worldwide patent for the technology which it hopes to install at other abandoned mines following the success of this trial.

Source: BBC

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Taxonomy

• Water
• Treatment
• Heavy Metal Removal
• Technology
• Water Treatment Solutions
• Environment
• Pollution
• River Engineering
• Mining Development
• River Basin management
• River Restoration
• Heavy metals