Background
During the 1960’s, the current A465 was built as a single three lane carriageway with two lanes facing uphill and one facing downhill. Improvements on this carriageway have been suggested since the 1990’s and the development of the A465 is a vital socio-economic project for the Heads of the Valleys area.
The road improvement project began in early 2021 and is expected to last until 2025. The total estimated cost of sections 5 to 6 is over £590 million and is being operated by FCC – a Spanish construction company.
The Overall Objective
Due to the increase of congestion and collisions throughout poor visibility areas on the A465, the overall objective for the project is to improve traffic flow and make it safer to overtake. To support creating a safer carriageway, there will be increase visibility around junctions along with an improvement to access for key services jobs and markets that support inward investment to areas such as the Ebbw Vale Enterprise Zone.
Solution
Siltbuster designed and mobilised a 60m3/hour two-stage flow proportional chemical dosing and solids removal system. The modular solution comprised of one MT8 Mix Tank with a chemical dosing stand and two HB50 Lamella Settlement Tanks. The mix tank provided coagulant and flocculant proportional dosing to increase the size of the suspended solids in the water, causing them to favour gravity and settle in our two HB50’s.
The system was installed within two days and is operational for seven days a week, maintaining consistent compliance.
The discharged water had to meet a discharge criteria of total suspended solids in a concentration of less than 60mg/l and a pH between 6 and 9. Siltbuster’s solution and system worked so well that the washwater produced had a total suspended solids concentration of less than 10mg/l.
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