Wastewater steel slag found to enhance concrete strength

Researchers have shown how a by-product of steel manufacturing can be used to treat wastewater and make stronger concrete, in a zero-waste approach to help advance the circular economy.

Produced during the separation of molten steel from impurities, steel slag is often used as a substitute aggregate material for making concrete.

According to an RMIT University statement, steel slag can also be used to absorb contaminants such as phosphate, magnesium, iron, calcium, silica and aluminium in the wastewater treatment process, but loses its effectiveness over time.

“Engineering researchers at RMIT University examined whether slag that had been used to treat wastewater could then be recycled as an aggregate material for concrete,” the statement reads.

“The concrete made with post-treatment steel slag was about 17 per cent stronger than concrete made with conventional aggregates, and eight per cent stronger than raw steel slag.”

Water engineer Biplob Pramanik said the study was the first to investigate potential applications for “sewage-enhanced” slag in construction material.

“The global steel making industry produces over 130 million tonnes of steel slag every year. A lot of this by-product already goes into concrete, but we’re missing the opportunity to wring out the full benefits of this material,” he said.

In the study, civil and water engineering researchers found the chemical properties of the slag are enhanced through the wastewater treatment, allowing it to perform better when used in concrete.

“The things that we want to remove from water are actually beneficial when it comes to concrete, so it’s a perfect match,” Dr Pramanik said.

“While there are technical challenges to overcome, we hope this research moves us one step closer to the ultimate goal of an integrated, no-waste approach to all our raw materials and by-products.”

Civil engineer Rajeev Roychand said the initial study was promising, however further research was needed to implement the approach at a larger-scale, including investigating the long-term mechanical and durability properties of enhanced slag.

“Steel slag is currently not in widespread use in the wastewater treatment industry – just one plant based in New Zealand uses this by-product in its treatment approach,” he said.

“But there is great potential here for three industries to work together – steel making, wastewater treatment and construction – and reap the maximum benefits of this by-product.”

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Victorian Premier’s Sustainability Awards 2018 finalists revealed

The finalists have been announced for the 2018 Victorian Premier’s Sustainability Awards, which recognise individuals, communities, organisations and businesses that are driving a sustainable future.

Winners will be announced at the Premier’s Sustainability Awards gala dinner at The Forum on Melbourne on 11 October.

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There are ten different categories for the awards with Premier Daniel Andrews selecting two overall winners of the Premier’s Regional Recognition Award and the Premier’s Recognition award.

Victorian Environment Minister Lily D’Ambrosio said the finalists in this year’s Premier’s Sustainability Awards are an especially diverse group from every sector in Victoria.

“I congratulate all finalists for their innovative work – using resources wisely and promoting sustainable practices here in Victoria,” Ms D’Ambrosio said.

The Finalists for 2018 are:

Built Environment

  • City of Greater Bendigo, Lovell Chen, Nicholson Construction – Bendigo Soldiers’ Memorial Institute Passive House
  • Lendlease, CPB Contractors, WSP, Aurecon, Level Crossing Removal Authority and Metro Trains Melbourne – Caulfield to Dandenong Level Crossing Removal
  • RMIT University – RMIT Sustainable Urban Precincts Program

Community

  • Enable Social Enterprises – Expansion – Greener Futures Employability Program
  • Kelly Mrocki – The Girl Who Saved the Frogs Incursion
  • Kensington Compost – Kensington Compost

Education

  • Albert Park Preschool Centre – Keeping Our Promise to Bunjil
  • Beeac Primary School – Brolga Pathways
  • Dunkeld Kindergarten – Educating Future World Leaders

Environmental justice

  • Department of Health and Human Services – Elenara House Sustainable Rooming House Upgrade
  • GWMWater (Grampians Wimmera Mallee Water Corporation) – Memorandum of Understanding with Dja Dja Wurrung – South West Loddon Pipeline
  • Moreland City Council and Moreland Energy Foundation – Cooling Communities

Environmental protection

  • Extreme Dents – Eso-friendly Automotive RepairPOD
  • Yume Food – Build a Marketplace Exclusively for Surplus Food to Reduce Food Waste
  • Zoos Victoria, Phillip Island Nature Parks – When Balloons Fly

Government

  • City of Melbourne, City of Port Phillip, City of Yarra, City of Moreland – Melbourne Renewable Energy Project
  • Department of Justice and Regulation – Recycle, Reuse, Donate Woodwork Program
  • Gannawarra Shire Council – Gannawarra Large Scale Solar

Health

  • Australian Nursing and Midwifery Federation Victorian Branch – Nursing for the Environment
  • Beaconsfield Dental – Beaconsfield Dental Health
  • Western Health – Changing Anaesthetic Gases at Western Health

Innovative products or services

  • BCH – Whole Garment Design
  • PonyUp for Good – PonyUp for Good
  • Yume Food – Build a Marketplace Exclusively for Surplus Food to Reduce Food Waste

Large business

  • IKEA Richmond – IKEA Richmond Refurbishment Project
  • Telstra Corporation – Murra Warra Wind Farm harnessing long-term renewable energy supply

Small and medium enterprises

  • Extreme Dents – Eco-friendly Automotive RepairPOD
  • Revolution Apps – Compost Revolution
  • Yume Food – Build a Marketplace Exclusively for Surplus Food to Reduce Food Waste

Building a more resilient sector: Sustainability Victoria

Waste Management Review speaks to Stan Krpan, Chief Executive Officer at Sustainability Victoria, about the organisation’s future approach to data capture, Victoria’s e-waste ban to landfill and the health of the waste sector.

Read moreBuilding a more resilient sector: Sustainability Victoria

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