Metro Tunnel waste to help build Melbourne homes

Clay waste from Melbourne’s Metro Tunnel Parkville Station project will be converted into new bricks for residential construction.

More than 80 Olympic sized swimming pools worth of material will be excavated as part of the project to make way for the new underground station.

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There are three stages to the project, with the first stage expected to provide around 300,000 tonnes of clay, enough to produce around 10 million bricks.

PGH Bricks and Pavers Regional General Manager Andrew Peachey said with the other two potential stages, there is a potential to produce around 30 million bricks.

“We are very committed to recycling this type of material as much as possible. Not only is it better for the environment – re-using waste rather than sending it to landfill – there’s also the social benefit of its use to build homes for new residents in the suburbs of Melbourne,” Mr Peachey said.

“Normally we would extract this clay from our own quarry, so recycling waste from construction sites also serves to provide longevity at our facility and continuity of work for everyone employed there.

Works began on the site on 14 January below Grattan Street, between Leicester Street and Royal Parade.

Victorian Acting Premier James Merlino said significant work is ramping up at the site of the station.

“The Metro Tunnel will make travelling to the renowned Parkville health, education and research precinct easier than ever before, slashing travel times by up to 20 minutes in each direction,” he said.

Victorian Minister for Transport Infrastructure Jacinta Allan said the government is working on providing Victorians with project to improve transport infrastructure.

“We are undertaking a monumental engineering feat as part of the Metro Tunnel, including constructing new train stations deep beneath some of Melbourne’s busiest areas,” she said.

The first train is expected to run through the tunnel in 2025.

Recycling biosolids into bricks

Image Credit: RMIT University

New research has found a way of turning biosolids from sewage into cheaper, higher performing bricks suitable for the construction industry.

A research team from RMIT University has developed a fired-clay brick as a sustainable solution for the wastewater treatment and brickmaking industries.

The bricks are made up of biosolids, a by-product of the wastewater treatment process, and were found to have a lower thermal conductivity than other bricks, meaning they will transfer less heat and potentially give buildings higher environmental performance.

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The research examined the physical, chemical and mechanical properties of fired-clay bricks incorporating different proportions of biosolids, from 10 to 25 per cent.

Researchers found brick firing energy demand was cut almost in half for bricks that incorporated 25 per cent biosolids, due to the organic content and could considerably reduce the carbon footprint of brick manufacturing companies.

Around five million tonnes of the biosolids in Australia, New Zealand, the EU, US and Canada currently go to landfill or stockpiles each year. By using a minimum of 15 per cent biosolids content in 15 per cent of the bricks produced, the research team estimates around five million tonnes could instead be used for construction.

The bricks have passed compressive strength tests and analysis demonstrated heavy metals are largely trapped within the brick. Biosolids can have significantly different chemical characteristics, so the researchers recommend further testing before large-scale production.

Lead investigator Associate Professor Abbas Mohajerani said the research sought to tackle two environmental issues – the stockpiles of biosolids and the excavation of soil required for brick production.

“More than 3 billion cubic metres of clay soil is dug up each year for the global brickmaking industry, to produce about 1.5 trillion bricks,” Mohajerani said.

“Using biosolids in bricks could be the solution to these big environmental challenges.

“It’s a practical and sustainable proposal for recycling the biosolids currently stockpiled or going to landfill around the globe,” he said.

The results of a comparative Life Cycle Assessment and an emissions study conducted as part of the research confirmed biosolids bricks offered a sustainable alternative approach to addressing the environmental impacts of biosolids management and brick manufacturing.

The research, funded by RMIT University, Melbourne Water and Australian Government Research Training Program scholarships, is published in the “Green Building Materials Special Issue” of Buildings.

Pictured: Associate Professor Abbas Mohajerani. Image Credit: RMIT University

Victorian recycling research and development grants now open

Sustainability Victoria has opened applications for Research, Development and Demonstration Grants of up to $200,000 for projects that can increase the quality of recycled products sold in Victoria.

Businesses, local governments and researchers can apply for grants between $50,000 and $200,000 to help stimulate markets for products made from recovered resources.

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Projects that investigate one or more materials which have specific supply or demand side barriers which could be overcome with support from the government are encouraged to apply.

Concrete and brick, electronic waste, glass, organic material, paper and cardboard, plastics, rubber and textiles have all been identified as targeted materials for the grant.

The grants have been designed to support the industry in commercialising new products and processing approaches and to increase the end market uptake and demand for the targeted materials.

Successful applicants will have their projects matched dollar for dollar by the state government.

Previous research projects included alternative uses for glass fines and flexible plastics in construction and manufactured products, such as railway sleepers, plastics in concrete footpaths, glass in non-load bearing concrete and roof tiles made from glass waste.

Sustainability Victoria CEO Stan Krpan said the grants would increase job creation, develop quality products for end markets and increase investment in products made from recovered resources.

“Recent shifts in the current international recycling in gives Victoria greater impetus to develop local markets for the products we can recycle,” Mr Krpan said.

“It is crucial such markets are developed so the value of recovered resources is realised.

“This funding provides industry the opportunity to develop and trial new or existing products and specifications that use significant and reliable quantities of targeted materials,” he said.

The program will also inform the industry of the possible opportunities to use recovered materials in manufacturing to support using products made from recycled content.

“Recycling is an increasingly important community issue, and we are committed to maximising the opportunities to support new markets that use significant and reliable volumes of priority materials,” Mr Krpan said.

“It’s also an opportunity for universities and industry to work together to develop practical solutions to an important, and costly, community issue, which will benefit us all.

For more information about applying for the grant, click here.

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