Bellozanne STW Rising Main Lining

About the project

Danaher & Walsh was appointed by nmcn PLC to carry out specialist lining works at a sewage treatment works facility on the Channel Island of Jersey.

Key details

nmcn PLC
Project value
Summer 2020

Key aims and challenges

nmcn is carrying out a £60m project to design & build a new sewage treatment works in Bellozanne, near St Helier, on behalf of the States of Jersey. 

The major upgrade is taking place whilst keeping the existing, 64-year-old facility fully operational.

Danaher & Walsh was engaged to carry out the specialist relining of over 850m of 24" (approximately 600mm) cast iron rising mains, dating from 1956.

How did we do?

The lining product used was Applied Felts’ AquaCure, a hybrid glass-reinforced felt liner. This product was selected because it was able to meet the exacting requirements of the scheme. The liner used was just 25mm thick, but is specified to withstand 10 bar operational pressure. The stretching properties of the liner ensured a very close fit with the host pipe. Furthermore, the liner has the chemical resistance necessary to protect against sewer effluent elements.

The installation took place using the inversion technique. Curing method differed across sections – some areas using hot water and some using steam. The largest single length of installation in one inversion/cure was 284m.

Working on a scheme of this scale and complexity would usually require very detailed logistical planning to ensure that personnel, machinery and materials are on site at the correct times. However, this requirement was exponentially increased owing to the site’s location in the Channel Islands.

Months of planning went into ensuring that all elements were in place to enable to the project to be a success. Close cooperation with our supply chain helped this to happen. Vehicles, plant and equipment were sent to the island by ferry, with remaining staff and operatives travelling by air.  

The team faced additional major challenges owing to COVID-19, and the strict quarantine laws introduced by the States of Jersey. This added the major complication of having to isolate personnel in hotels prior to their admittance to site. 

On-site liaison and cooperation with our client and other contractors was of paramount importance to ensure the progression of our works whilst integrating with the works of others. Informal daily meetings and formal weekly meetings took place to coordinate activities. We also used videoconferencing extensively to maintain close liaison with client contacts and stakeholders based remotely from the site.

From the client...

The professionalism, knowledge, honesty and calm approach shown to overcome challenges is a huge credit to your team, This was a major benefit to myself (nmcn), and our client (States of Jersey), as it instilled us with the confidence that we had the best specialist subcontractor for this process, even when the day wasn't going our way.

Simon Reeve, Design Manager, nmcn PLC