Resource recovery and utilising alternative construction materials to support urban growth came under the spotlight as part of the recent Engineering Insights virtual event hosted by wet processing industry experts CDE.
The second edition of the event, held across three days from 18-20th May, followed a hugely successful 2020 inaugural conference which was developed in response to a desire for industry professionals to engage in global learning and networking in the absence of international tradeshows and in-person conventions.
To support the continued sharing of insights and facilitating pertinent discussions regarding the global market, CDE convened industry leaders from across Australia and programmed a series of dynamic presentations discussing the supply and demand of geological construction materials and landfill diversion in the demolition industry.
Greater Sydney’s present and its future
According to the Greater Sydney Region Plan, published by the Greater Sydney Commission, its population grew at an annual rate of approximately 2.5% for most of the 20th century. Today, that makes Greater Sydney one of the top 10 fastest-growing regions in the Western world.
And that rapid population growth and significant demographic shift is set to continue. The plan also projects that an additional 3.2 million people will call Greater Sydney home by 2056.
Dugald Gray, Principal at Ecoroc, said that of the 40 million tonnes of construction material required to meet demand in the region, 42 per cent came from alternative materials including virgin excavated natural material (VENM) and sandstone.
“They’re used in large quantities, they’re low value, they’re generated within the city, and from a sustainability perspective they’re fantastic,” he said during a panel discussion assessing the supply and demand for geological construction materials in global cities.
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He was joined by Daniel Webber, CDE’s regional manager for Australasia; Mitchell Bland, Managing Director at RW Corkey & Co; and Quarry Magazine editor Damien Christie.
Gray added that such materials can be used as a substitute for road base, hard sand and other materials used for filling voids, highlighting that it also reduces the burden on finite virgin sand and aggregates by ensuring quarry operators can earmark freshly quarried materials for higher strength and higher value applications.
“As a consequence, what that allows for is hard rock quarries to maximise the yield of aggregates they produce for concrete or asphalt.”
‘We need to double our historic recycling rate’
Mike Ritchie, managing director at MRA Consulting Group, one of Australia’s leading environmental consultancy firms, remarked that New South Wales has in place an 80 per cent landfill diversion target for construction and demolition (C&D) waste by 2030, adding that more work needs to be done to meet it.
“We are not there yet but it is positive, C&D recycling rates currently sit at 74%. C&D is highly recyclable due to its consistent strains of materials and therefore lends itself to higher recovery rates. Government are using landfill levies to move the industry towards hitting the 80% target,” Ritchie said.
Ritchie was speaking during the Resource Recovery and Diversion from Landfill for the Demolition Industry session where he was joined by Mark Smith, CEO of Waste Recycling Industry Association Queensland (WRIQ); Mike Wheeler, editor of Inside Waste; and Marcus Barber, representing the City of Greater Dandenong.
“We haven’t reduced the amount of tonnes landfilled in the last 20 years,” Ritchie explained.
“To hit the 80 per cent target, we are going to have to do a lot more work. To reach this national target by 2030, we need to double our historic recycling rate. This is only possible with the right market and pricing signals.”
He said government levies have done the heavy lifting in terms of recycling growth over the past two decades. Analysis by his consultancy showing the relationship between recycling rates and levies confirms the higher the levy the greater the recycling rate.
“We need to continue to advocate to the government to ensure everyone understands the benefits of levy and price signals in terms of making construction and demolition recycling profitable and worth investing in.”
He added that the recycling industry is worth investing in.
“We have major investors coming into the waste market now to invest in C&D companies.”
While Ritchie focused on landfill diversion, Smith highlighted the importance of how products and buildings are designed to begin with and the need for an end-of-life solution for products used.
And advocating for the use of recycled products in the construction sector, Barber suggested concrete produced from C&D waste has its applications.
Referencing a UK-based customer, he said, “They have been bold, and they guarantee their products. They say this concrete is good enough for a car park…they’re maybe not going to build an airport runway with it but leave virgin extracted material for the right places.”
Virtual global learning
The packed three-day programme featured 16 sessions involving almost 50 speakers.
CDE’s CEO Marc Jennings said, “In 2020, despite the global circumstances, CDE utilised its network to bring together industry leaders and professionals virtually to discuss the prevalent issues of the day. We are proud that in 2021, we were able to build upon this and host our second Engineering Insights virtual symposium.
“We have continued to facilitate global learning and our conference was once again a huge success, as 600 industry professionals registered, engaging with our event from around the world.
“Challenges in our industry such as water management, sand depletion and sustainable mining continue to dominate important conversations, and we believe it is of great importance that industry experts sustain these virtual discussions in order to aid progression, indeed as the world progresses out of the global pandemic.”