Two Team Van Oord partners have combined on a project to provide improved protection for a wastewater outfall pipe on England’s north east coast.
The works at the Withernsea Wastewater Treatment Works (WTW) are being carried out by Mackley and Van Oord, on behalf of Yorkshire Water.
Constructed in 1991, Withernsea WTW serves between 6,000 and 12,000 residents and is located on the Holderness coast, one of the fastest eroding coastlines in Europe.
The Withernsea facility is at risk of falling into the sea within the next five years because of coastal erosion, and in time Yorkshire Water wants to relocate the treatment works.
The first step in the project involved building a temporary ramp to enable a 30t excavator to descend from the cliff top onto the beach, and vice versa.
The ramp was constructed with one-ton bulk bags covered with sand for protection. However, the sand has to be replenished every day due to high tides washing it away.
The pipeline is being protected with 4t Kyowa Filter Units which provide protection from scour damage, while at the same time benefitting the surrounding environment.
The Kyowa unit comprises mesh net and rocks, and creates the ideal environment for small fish and plants to live in the interspace within it. The system is relatively new to the UK – it was first used by Team Van Oord on the River Mole Asset Recovery programme (2014/15) – but has been used in Japan for many years.
Andy Bosman, Project Manager, said:
“The Kyowa bags are delivered to site and then lifted down onto the beach where the excavator carries them out to low water and places them over an existing waste water discharge pipe.
“The bags are placed two wide from low water back to the cliff face to give temporary protection to the pipeline, due to the main pipe being exposed to the open water and the risk of damage or rupture to the main pipe causing environmental pollution to the east coast of Yorkshire.”
10 January 2018