CRDC-supported PhD candidate at the University of Queensland (UQ), Rhys Pirie and his supervisor, Professor Damien Batsone have developed a method to extract liquid silicate from waste glass, and it can be used to make thousands of products - including fertiliser.
This new process of turning waste glass into everyday products could save tens of millions of tonnes of glass from going to landfill everyday - while also potentially benefiting cotton growers.
Waste glass is currently either landfilled at negative cost or used as road base. The glass processing technology has the potential to revolutionise multiple supply chains. In terms of fertiliser, this is one of the largest variable cost inputs to farmers and new forms of fertiliser which may be more efficient from an agronomic perspective are generally not more efficient from an agro-economic perspective. Resolving this requires low cost ways of improving fertiliser efficiency and ultra-low cost plant-available silica is a promising avenue.
“We estimate the process is more than 50 per cent cheaper than conventional ways of producing silicate,” Mr Pirie said.
“It requires less energy, raw materials and capital, and that’s before you consider the reduced social and economic costs compared to landfilling material.”
UQ’s method also leaves behind little waste, with nearly all of the glass being turned into saleable products.
Mr Pirie started to look into the possibilities of glass recycling after talking to Professor Batstone from UQ’s Advanced Water Management Centre, who specialises in converting waste into high-value products.
The pair drew inspiration from ABC’s War on Waste series.
“The transition towards circular economies is a movement which is gaining momentum and something I’ve always been interested in,” he said.
"My PhD has highlighted how we need to make use of both the raw materials in ‘waste’ streams and the energy embodied in them during manufacture.
“That’s what this process does and we’re pretty confident that it will create positive, far-reaching and virtuous economic cycles.”
UniQuest, UQ’s commercialisation company, has filed a patent covering the process and is now seeking commercial partners.
For the remainder of his PhD, Mr Pirie is looking at ways in which waste glass could also be used to create a low-cost silicon-based additive to increase fertiliser efficiency.
Mr Pirie works between the UQ School of Chemical Engineering and the School of Agriculture and Food Sciences.
He was awarded the Warwick and Nancy Olsen PhD Scholarship for his work, and in 2018 was the receipient of the CRDC-supported ABARES Science and Innovation Award for his focus on re-purposing organic wastes (such as livestock manure, biosolids and cotton gin trash) as fertilisers and soil ameliorants: helping growers optimise resource efficiency and improve their environmental impact.
The research was co-funded by CRDC and the Department of Agriculture and Water Resources.