ECS refurbishes giant screw pump to keep sewage works operating for decades
Wessex Water’s Avonmouth wastewater recycling, bioresources and renewable energy park is set to serve its 1,000,000+ population for decades to come following a major overhaul to inlet pumping station, which is one of the largest of its kind in the UK.
A replacement screw body was made in Holland by partner company Landustrie working to a design that followed that of the original screw. On this occasion Landustrie had to make the screw as a mirror image of their usual practice because the Avonmouth screw rotates in the opposite direction to the Landustrie standard, this allowed it to be utilised with the existing drive train. Made in mild steel, it has a high-performance corrosion-resistant coating that will give it a working life measured in decades in line with the WIMES specification. Once the fabrication was complete, ECS organised specialist shipping to get it to site.
“As part of this contract, we also made new side profiles,” says Jake Laughton, who managed the project for ECS. “The replacement pump bodies were almost identical to the original design, but we used finite element analysis techniques to optimise them for withstanding the pumping pressure based on new standards.”
While the top bearing was in good condition and could be reused, the bottom bearing needed replacement. ECS installed a free issued bottom bearing that matched the other screw pump at the inlet, thus minimising parts inventory for the works and minimising financial impact to the client.
The first stage in refurbishing the pump was to drain down the pump and remove the old screw. Jake recalls: “We had to make and fit a special stanking plate to the penstock before we could start the drainage to ensure protection of the works. We needed a crane for removing the old screw and fitting the new one so this was also used for installing the plate for the client.”
Jake, like many other ECS employees, is a qualified crane appointed person, this allows ECS to plan and undertake crane operations quickly, efficiently and safely without having to bring in outside contractors and keeping costs to a minimum.
With the old screw removed it was time to break up and remove the old screed. For this ECS used a remote-controlled, robotic breaker so that the task was completed quickly and safely.
With the screw pump now refurbished Wessex Water’s Avonmouth wastewater recycling, bioresources and renewable energy park is set to continue serving its local population well into the future.