Project Sheet: Rhyl Waste Recycling Centre
- Denbighshire Country Council
- George Brown Consultancy
- £2.5 million
- site investigation including groundwater monitoring and the excavation of boreholes and trial pits
- desk study, provide geotechnical and environmental recommendations
- design of the earth works for the recycling centre and cycle track.
Description of Project
Denbighshire County Council proposed to redevelop an old industrial estate with the construction of the following:
- Waste Recycling Centre
- BMX track
- Cycle track
- Car Park
- Changing room facilities
- A new access road into the development
GroundSolve Ltd was approached to design the earth works related to the recycling centre, BMX track, cycle track and the changing room facilities.
As the location of the various structures had not been determined prior to the desk study, a significant degree of value engineering could be undertaken. The desk study identified that the site was underlain by an old landfill dating from the 1950’s, whereby waste had been tipped into the River Clwyd behind a series of earth bunds.
This enabled the most cost-effective location for the Waste recycling centre to be established, which was then confirmed by the site investigation.
In addition, the desk study and site investigation confirmed that an old road had been constructed across the site along with foul and storm drainage. Further investigations confirmed that these could be re used leading to significant savings.
The design involved splitting the original industrial estate into two. The eastern half was used for the Waste Transfer site and the western half became the BMX track.
The new waste centre has been built on an old landfill site (1950-1985). GroundSolve Ltd were appointed to carry out a site investigation and desk study to identify the most suitable location for the development. This involved the excavation of trial pits and boreholes to identify the underlying ground conditions.
Following the site investigation and desk study a report was issued giving geotechnical and environmental recommendations.
As the structures were to be constructed on an old landfill they would require deep foundation, which caused some environmental concern regarding the possible spread of contamination from the landfill down into the existing aquifers.
To address this issue Vibrated Concrete Columns (VCC’s) were installed to depths of around 12m founded in the underlying glacial till, which negated this issue.
An access road was built extending from the existing Marsh Road towards the caravan park to the east, providing access to the changing rooms and the recycling centre.
The cycle track circulates the pond and reed bed, being 1.25km in total and the longest in Wales at the time. It is located to the south of the recycling centre and BMX track.
The pond and reed beds are lined with impermeable geo-membrane and compacted site won clay. The maximum depth of the pond is 1m and the reed beds are approximately 0.5m deep. There is also a permanent pond in the centre of the reed beds measuring about 2m deep. The two bodies of water are linked with a channel, and water leaves the reed bed through a weir, entering the Rhyl Cut through an outfall.
Environmental and Sustainability Issues
Large areas of landscaping were designed to reduce the visual impact of the waste treatment station as much as possible as well as making the BMX and cycle tracks as aesthetic as possible. Trees were planted around the recycling centre and a large pond and reed bed were created around the cycle track. The total area of the pond and reed bed equated to about 5,000 square meters.
During the consultation process, Environment Agency Wales required a controlled waters risk assessment to be undertaken. GroundSolve Ltd commissioned Smith Grant LLP to carry out the monitoring of water in the River Clwyd. It was undertaken at 3 monthly intervals throughout the works. In total, 4 rounds of monitoring were taken.
On completion of the works, GroundSolve Ltd in partnership with George Brown Consultancy were awarded the ICE Wales Roy Edwards award for ‘An outstanding example of engineering”.