OnSite rehabs Peterborough trunk sewers and manholes.

OnSite has rehabilitated trunk sewers and manholes across Peterborough. The new structure and serviceability of the assets will ensure the optimum performance of Peterborough’s sewer network for many years to come.

The Problem

A concrete trunk main and its manholes had been aggressively attacked by Hydrogen sulphide causing a 1500mm trunk main to collapse within a housing estate.

OnSite conducted extensive sonar and CCTV surveys of the surrounding sewers and manholes. This revealed severe failings and work was urgently required but could not utilise open-cut techniques. OnSite has market-leading, innovative equipment and methods to restore assets structurally, timely and without the need of costly over-pumping set-ups.

The Solution

Using a combination of specialist teams, OnSite was able to solve the problem in a safe and timely manner.

The OnSite Pipelining team installed multiple liners using Ultra Violet (UV) Cured in Place Pipe (CIPP) with its fast installation and curing time. UV liners offer a perfect structural property with smaller design thickness so the sewers Internal Diameter (ID) is not reduced significantly.

This client had a large diameter UV installation with each of them being in excess of 100m in length. Each section was given to OnSite as a dry sewer by flow diversions and minimal over-pumping of the residual flows. This allowing for cleaning and rehabilitation of each length accordingly.

The sewer network, 10 No. manholes of different dimensions, and the trunk of the sewer all required rehabilitation due to extensive corrosion caused by hydrogen sulphide gases.

The OnSite Specialist Maintenance team’s focus was on rebuilding the assets using specialist mortars that were applied to enhance the manholes structure and restore it back to its original status. They then applied a coating to the mortar which will protect the manhole walls from further hydrogen sulphide attack. The majority of these works are managed and delivered under standard flow conditions without the need for complex over-pumping which was a key driver in this work.

 In Action

OnSite can help over come many issues, such as lack of asset drawings. In this case, OnSite surveyed and provided a clear diagram of the network, giving a coherent overview and facilitating the initial plan.

The findings established that flow could be diverted from one system to another with the aid of an inflatable stopper (bung). These findings minimised the requirement for an expensive over-pumping set up (that initially, the client was concerned they would need). This allowed time to consider the best structural and innovative designs to enhance and rehabilitate the sewer network under normal flow conditions.

The scheme has been divided up into phases over the coming years allowing the client to focus on preventative maintenance, rather than repair, maintaining optimum performance for their sewers.

OnSite is this client’s only framework contractor for relining and manhole rehabilitation. Developing an understanding of how the client works is key to OnSite’s formula for success. Effectively integrating with the client’s ways of working allows OnSite to deliver on time, within budget, to the client’s design requirements and without incidents or accidents.

OnSite will partner with customers to offer improvements and insights to ensure their networks are running as efficiently as possible. Innovation and alliance are at the heart of what we do. Sharing resource and collaborating to ensure every challenge is met with a first-class solution, with performance and safety at the forefront of every project.

If you would like to discuss this further please call us on
01905 340 054 or e-mail us at solutions@OnSite.co.uk


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