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Young Engineer 2012 Report


Day one began with a visit to head office. Introductions and meet and greets. After a warm welcome, I was taken aside for a presentation to outline a typical day out in the field. After covering the all-important compliance procedures, I was taken through a typical relining job step by step. The processes were familiar, but the techniques deployed different. The spiral wound lining process was of particular interest as it has not yet been used by Wessex Water, in fact only a handful have been installed in the UK,  yet this technique is common practice in Australasia and other continents across the globe. In addition to their lining procedures I was given an insight into the other products and services Interflow provide. It was encouraging to learn that Interflow managed both small schemes and complex projects, offering their clients solutions using a diverse range of pipeline rehabilitation techniques.


On day two I was invited to site. Interflow were carrying out a large project for Sydney Water to renovate three 900mm diameter lengths of sewer spanning up to 12km. Exposed concrete and mortar within the pipes had suffered from Hydrogen Sulphide (H2S) attack. Once the degraded concrete was removed with high pressure jetting, Interflows Rotaloc system was being deployed to seal the pipes against further attack. The installation of GRP panels has been used in similar instances in the UK by Wessex Water. Upon further investigation it became apparent to me that H2S attack is more problematic in Australia and indeed in warmer climates as the deterioration of cementious materials is accelerated by increased temperatures.

In the afternoon I visited Interflow's CIPP and wetting out facility. It was clear that spiral wound technology took precedence over CIPP at Interflow. However CIPP was still offered, typically in situations where the use of spiral wound techniques was limited for example where sharp bends needed negotiating and for lining ovoid pipes.


A trip to Canberra where I met with a representative of ACTEW Water. The meeting provided a good comparison of asset management strategies. Site visits had also been arranged to witness both spiral wound lining using Interflows expanda profile and also pipe bursting of foul and potable water mains. Pipe bursting practice was of particular interest here as I have become involved in a number of similar schemes back home. Since the transfer of private sewers in October 2011, Wessex Water has seen a sharp increase in the renovation of small diameter pipes in residential areas that had previously been privately owned. A large number of these pipes have become excessively deformed to the extent that lining is not viable and pipe bursting has been proposed as an alternative to open cut. Consultation with the engineers involved on this project provided a good opportunity to share ideas.


A slight change of itinerary meant I returned to HO on Thursday. The unexpected return visit provided a good opportunity to catch up on my workload back home! In the afternoon a site visit had been organised to witness an expanda installation. A 150mm dia sewer was being relined under the instruction of Sydney Water. The more I was exposed to the expanda system the more fascinated I became by the ease of installation.


On Friday, further site visits had been arranged in and around Sydney. I began the day on site for another expanda liner installation this time on a 225mm dia sewer. Having witnessed the lining installation we moved on to shadow a lateral connection sealing gang installing interflows "interfit" top hat system. I was very impressed by the slickness of operation and the quality of the finished product. Later on in my visit I spent time with research and development who were working to enhance and develop this particular product.


My second week started with a visit to Sydney Water HQ. I met with their sewerage asset manager who delivered an informative presentation on their sewer rehabilitation strategy – similar to that deployed by Wessex Water, involving a risk based approach. In the Wessex Water region our largest conurbation is the city of Bristol where we meet the needs of around half a million sewerage customers. The scale of Sydney waters waste operation is vast in comparison as they are serving a population in the region of 4 million in one confined settlement. As a result their large diameter tunnel network is vast. Large diameter pipes are typically constructed in concrete and so assessing the condition of these assets to monitor H2S attack was high on their agenda. 

Site visits followed later in the day to include the rehabilitation of an access shaft and the renovation of a large diameter concrete sewer suffering H2S attack.


On Tuesday morning I set off for Adelaide, slightly concerned by the 40 degree temperatures that had been forecast! Interflow were working to renovate a large diameter concrete sewer suffering H2S attack. Again the Rotaloc system was being used following high pressure jetting to remove deteriorated concrete. High flows within the existing system posed problems. It is possible to use Rotaloc in live flows, but within reason – the working environment needs to be safe enough to allow man entry and a certain amount of the pipe needs to be visible to ensure the profile is winding effectively. A significant overpumping set-up had been provided and installed by Interflowto allow the job to progress. Later, I willingly returned to the warehouse to get some rest bite from the sun but also for a live Rotaloc demo. It is difficult to fully appreciate the system from above ground as the machine follows the profile along the pipe and spends most of its time out of view.


On day two in Adelaide I was accompanied by a representative from Interflow on a trip to SA Water. Similarly to my trips to Sydney and ACTEW, asset management techniques and project delivery processes were high on the agenda. The meeting was fulfilling but unfortunately subsequent site visits were not possible due to my return flight to Sydney.


Having spent the morning preparing, I proceeded to deliver a presentation to Interflow. Following a summary of our company history and asset management strategy, my presentation focused on the techniques we deploy and gave me an opportunity to demonstrate some our proud achievements. Wessex Water is somewhat unique as we have the only dedicated sewer renovation team of the 10 water and sewerage companies. Our engineers are trained to assess pipe condition and recommend solutions, before working closely with specialist contractors to deliver projects using innovative trenchless techniques.


On my final day I spent a fair amount of time in the warehouse. Tooling and equipment are built, serviced, repaired and stored here. This gave me the opportunity to operate kit and fully understand the working apparatus. I also spent time with the research and development team who were working on a series of projects to improve existing systems often in response to client needs. It was encouraging to learn that Interflow invest time and resources to help continually improve their products.

I also put some time aside for an interview with the ISTT!

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