03 May 2018

Natural Resources Wales (NRW) has announced that it has achieved impressive results in two innovative trials which use electrochemical treatment to clean up polluted mine water.

Wales’s industrial past means that its environment feels the effect of long-abandoned metal mines, which once produced lead, zinc and copper; these mines are now the source of severe pollution whose toxic discharges can have a severe impact on the water quality of the surrounding area. NRW is the body responsible for tackling metal mine pollution and it has been trialling cutting-edge technology in two trials at Cwm Rheidol and Frongoch, both locations where watercourses are heavily affected by mine run-off. 

At Cwm Rheidol, the organisation has been trialling a sono-electrochemical technique provided by Swansea firm KP2M Limited, trading as Power & Water. Now a popular tourist area, Cwm Rheidol was once home to mines producing lead and zinc, with production ending in the early 20th century. Two mine entrances still discharge highly acidic, orange water which contains high levels of zinc, lead and cadmium. 

Over the course of a year eight tonnes of metals are discharged into the Afon Rhiedol that impacts the river for 18km. “The mine is situated in a narrow, steep sided valley which is unsuitable for traditional treatment processes which require a considerable area of land,” explains Peter Stanley, water and contaminated land technical specialist for NRW. “So, KP2M Limited trading as Power & Water, a Swansea company providing research led solutions to the water industry successfully tendered to run a trial using an innovative sono-electrochemical technique.

 “Preliminary laboratory results were encouraging, and the small footprint of the equipment makes it particularly suitable to rugged upland locations where traditional passive pond systems simply will not fit.” Further independent laboratory results followed which confirmed the treatment’s success with raw samples showing metal removal of 87% while filtered samples confirmed 99.5% removal of metals. A full-scale system like the pilot trial, benefitting from added filtration to reduce fine particulate matter will be expected to achieve 98% or more reduction of metal loading.

Read the full article at WWT WET News