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A Case Study for Surface Water Remediation: Pembrokeshire




The development of a new 9.3km dual carriageway connecting Carmarthen to Pembroke Dock was undertaken in 2013. There was a high risk of water contamination to local water courses due to soil disruption during the construction process. Hydro quickly engineered a solution that would meet standards required on the roadway site. The solution provided four treatment plants to the Roadbridge site, operating when rainfall occurred. These systems were engineered and manufactured to specific flow rates and areas available on the roadway, this caused the bespoke development of different sized units. 


Due to the unearthing of soil during construction red sandstone and clay strata were exposed. With the high probability of rainfall these unearthed materials had great potential to pollute an array of nearby water courses. Over land water flow would wash over the exposed areas creating turbid water containing a high volume of suspended solids from mud and clay. Sediment loads would increase into water courses, reducing light penetration and oxygen levels, as such aquatic flora and fauna would be effected. The inherent probability of fish deaths were of concern particularly with prolonged exposure to this form of water pollution.


road-bridge-image.pngHydro Industries deployed four treatment plants to the Roadbridge site that used electrocoagulation to remove the suspended particles from the surface water. Conventional settlement methods would have proved difficult to remove the mud and clay content due to the negative charge of the particles holding them in suspension. Therefore a means other than gravity was required to separate the contaminant from the surface water and ensure that it was treated to the stringent regulatory discharge standards enforced by the Environment Agency. Hydro's technology has proven to be a fast, efficient and cost effective method of surface water treatment. We successfully mitigated any potential environmental damage and ensured that the Roadbridge project could continue without any further delay.