Australia’s sewerage networks are ageing. However, sewer repair or replacement can be both costly and dangerous.
Given the significant financial investment required, operators need to strike the balance between repairing too soon – and failing to extract maximum value – or leaving it too late and risking operational failure.
Further, a detailed condition assessment of a sewer pipe often requires confined space entry, with workers exposed to toxic gas and other physical and biological hazards.
Put simply, the task of keeping sewers well maintained in a safe and cost-effective manner is no easy feat.
Due to the challenges associated with condition assessments of sewer pipes, organisations around the world have been exploring the best ways to do this remotely.
Sewer crawler cameras using basic CCTV are becoming commonplace, while some are even in the process of building high-tech sewer robots.
However, none of the available innovations to date have the ability to both visually inspect the sewer pipes, while also capturing digital spatial data that would enable engineers to build a 3D model for maintenance works.
So, when the Central Coast Council asked KBR to perform a condition assessment on 640m of their 1.2m diameter Avoca and Terrigal tunnels without sending anyone down them, we decided to come up with our own solution.
Partnering with Emesent – a Brisbane-based autonomous 3D mapping solutions specialist – we designed a custom-built vehicle that was able to traverse the sewer pipe while also capturing imagery and rich spatial data.
We used a standard remotely operated vehicle (ROV) and fitted it with a Hovermap ST-X Mobile Laser Scanner and HD 360-degree CCTV technology.
However, traversing a pipe of this length and diameter with an ROV had never been achieved previously, so it took some trial and error before we were able to develop something that was able to be remotely controlled from above ground.
On its first official mission, the ROV successfully scanned over 640m of sewer pipe, 1.2m in diameter, between Terrigal and North Avoca – the longest stretch a vehicle of this type has ever completed.
While building the vehicle and successfully running it through the pipe was an achievement in itself, the real advantage is having the ability to capture the data required to build a 3D digital replica for future maintenance works.
The Emesent Hovermap ST-X scanner provides a high-definition Point Cloud model and associated imaging for a virtual assessment of sewer pipe condition, helping to identify major cracks, blockages, and structural wear with unprecedented precision.
The data is uploaded to Cintoo’s cloud-based application, transforming the data into high-fidelity 3D meshes used to create a digital replica of the sewer.
This workflow brings the site to the office and allows our team to inspect the internals of the sewer pipe remotely and safely.
By capturing a snapshot in time, the process can be repeated in future to identify and monitor changes within the sewer, meaning asset owners no longer have to guess the best time to replace or repair the pipes.
Plus, georeferencing and coordinating the data means we can precisely locate any areas along the length of the pipe that need to be repaired.
With significant investment needed for Australia's ageing water infrastructure in the coming decades, digital solutions that optimise repair timing and pinpoint locations will help reduce costs and extend asset lifetimes.
And with worker safety a key priority, eliminating the need for unnecessary manual inspections of confined and dangerous spaces makes digital alternatives to sewer inspections a win-win.
Hayden Robinson is KBR’s National Digital Engineering Technology Manager with 27 years’ experience driving project efficiencies through technical oversight and the adoption of established and emerging digital engineering technologies.
All images credited to Emesent.