Sometimes the best examples of sustainability come from the simplest of ideas. 

Our water business, in conjunction with joint venture partner Jaydo, has been busy building the nine-kilometre Lockerbie Main Sewer (LMS) pipeline, since last year, on behalf of Yarra Valley Water. 

The LMS is the next major stage of the $400m investment in water and sewerage infrastructure made to service the growing population in Melbourne's Northern Growth Corridor.

With an ongoing focus on taking a sustainable approach to our work, the team has been able to save more than 30 tonnes in carbon dioxide equivalents (CO2e), simply by utilising material that was a byproduct of construction.

Mineral and rock excavation work-site

Here's how they did it

A project like the LMS requires significant heavy civil construction, including excavating large amounts of rock for installation of the new sewer. The rock needs to then be disposed of, traditionally this may happen at a specialised landfill or quarry.

At the same time that these sites are excavating rock, they often require large amounts of crushed rock to use on haul roads, hardstands and crane pads. A hardstand is a heavy-load-bearing surface required for large and heavy vehicles that will be parked in an area for an extended period.

Working at one of the construction sites for the project just north of Melbourne in late 2020, the team identified an opportunity to utilise a large amount of the excavated rock on site. So, they set about repurposing it.

This involved crushing nearly 16,000 tonnes of surplus rock and, after ensuring that it met required compaction rates, using for the haul roads, hardstands and crane pads.

By crushing the rock on site, it reduced the amount of material that would have been procured and transported from the nearest quarry. In addition it meant that the 16,000 tonnes of excavated rock would not have to be disposed of at specialised landfill.

Steven Ross, General Manager of Capital Projects for Ventia said that the team showed great initiative in utilising the excavated rock on site.

The repurposing of materials on site not only saves on CO2 equivalent emissions and construction costs, it also minimises impact on the local area, and as a result, on surrounding communities.

Water pipe image