Examining resource recovery pathways for low carbon waste management in New South Wales, Australia

Madden, Benjamin B.

Examining resource recovery pathways for low carbon waste management in New South Wales, Australia

Madden, Benjamin B.

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Publication Type:: Thesis
Issue Date:: 2023

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Field	Value	Language
dc.contributor.author	Madden, Benjamin B.
dc.date.accessioned	2023-07-11T05:16:40Z
dc.date.available	2023-07-11T05:16:40Z
dc.date.issued	2023
dc.identifier.uri	http://hdl.handle.net/10453/171448
dc.description	University of Technology Sydney. Institute for Sustainable Futures.	en_US.UTF-8
dc.description.abstract	The household organic waste stream is problematic, with high rates of waste generation and landfill disposal. Through better management, this waste may be diverted from landfill to resource recovery processes, leading to emissions reductions and the realisation of circular resource flows. Limited data on emissions associated with waste systems in Australia makes assessing resource recovery pathways from a low carbon perspective difficult. This is important considering the transition towards circular economy management practices, which prioritise reduced environmental impacts of waste management systems. This study developed a modelling framework for estimating the emissions associated with the management of household organic wastes in New South Wales, and for evaluating resource recovery pathways from a low carbon resource recovery perspective. A probabilistic spatial disaggregation model was developed, used to estimate waste generation at the property lot level for households in the Greater Sydney and surrounding areas. These estimates were then combined with road network data in a route optimisation model, to estimate emissions from waste collection and transportation. Estimated transport emissions and estimated recovery and disposal emissions were used to characterise emissions over the entire organic waste management chain. Potential recovery pathways were then evaluated through scenario simulations and multi-criteria analysis. This work fills an important gap in the assessment of household organic waste management from a low carbon resource recovery perspective. Findings revealed lifetime emissions from landfill disposal accounted for approximately 56% of all household organic waste emissions. Household mixed-waste accounted for the majority of organic waste disposed to landfill, having the largest impact on overall emissions. Diverting food waste from the mixed-waste stream to dedicated organic waste collection was identified as key to low-carbon resource recovery. Significant potential emissions reductions were also found via fossil fuel avoidance through the deployment of anaerobic digestion. Findings from the analysis highlights the potential for food waste-only collection systems, which could encourage further diversion of food waste out of the mixed-waste stream and landfill, while also providing a cleaner feedstock for municipal-scale digestion. This suggests that the collection of combined food and garden organic waste favoured by councils in NSW may not be the best approach when considering emissions and higher value resource recovery. Considering also emissions intensive electricity supply reliant on fossil fuels, organic recovery can be geared towards offsetting fossil fuels with biogas from digestion—supporting a broader system evolution powered by renewable energy, and net zero emission objectives in the state.	en_US.UTF-8
dc.format	Thesis (PhD)
dc.language.iso	en_US	en_US.UTF-8
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/171448/1/thesis.pdf
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	© 2023 Benjamin B. Madden
dc.rights	au.edu.uts.lib/cph
dc.title	Examining resource recovery pathways for low carbon waste management in New South Wales, Australia	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*

Abstract:

The household organic waste stream is problematic, with high rates of waste generation and landfill disposal. Through better management, this waste may be diverted from landfill to resource recovery processes, leading to emissions reductions and the realisation of circular resource flows. Limited data on emissions associated with waste systems in Australia makes assessing resource recovery pathways from a low carbon perspective difficult. This is important considering the transition towards circular economy management practices, which prioritise reduced environmental impacts of waste management systems. This study developed a modelling framework for estimating the emissions associated with the management of household organic wastes in New South Wales, and for evaluating resource recovery pathways from a low carbon resource recovery perspective. A probabilistic spatial disaggregation model was developed, used to estimate waste generation at the property lot level for households in the Greater Sydney and surrounding areas. These estimates were then combined with road network data in a route optimisation model, to estimate emissions from waste collection and transportation. Estimated transport emissions and estimated recovery and disposal emissions were used to characterise emissions over the entire organic waste management chain. Potential recovery pathways were then evaluated through scenario simulations and multi-criteria analysis. This work fills an important gap in the assessment of household organic waste management from a low carbon resource recovery perspective. Findings revealed lifetime emissions from landfill disposal accounted for approximately 56% of all household organic waste emissions. Household mixed-waste accounted for the majority of organic waste disposed to landfill, having the largest impact on overall emissions. Diverting food waste from the mixed-waste stream to dedicated organic waste collection was identified as key to low-carbon resource recovery. Significant potential emissions reductions were also found via fossil fuel avoidance through the deployment of anaerobic digestion. Findings from the analysis highlights the potential for food waste-only collection systems, which could encourage further diversion of food waste out of the mixed-waste stream and landfill, while also providing a cleaner feedstock for municipal-scale digestion. This suggests that the collection of combined food and garden organic waste favoured by councils in NSW may not be the best approach when considering emissions and higher value resource recovery. Considering also emissions intensive electricity supply reliant on fossil fuels, organic recovery can be geared towards offsetting fossil fuels with biogas from digestion—supporting a broader system evolution powered by renewable energy, and net zero emission objectives in the state.

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