Implementation And Monitoring Of On-Site Sanitation Systems To Mitigate Public Health Risks In Low-and Middle-Income Contexts

Mills, Freya A.

Implementation And Monitoring Of On-Site Sanitation Systems To Mitigate Public Health Risks In Low-and Middle-Income Contexts

Mills, Freya A.

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Publication Type:: Thesis
Issue Date:: 2025

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Field	Value	Language
dc.contributor.author	Mills, Freya A.
dc.date.accessioned	2025-10-21T02:42:56Z
dc.date.available	2025-10-21T02:42:56Z
dc.date.issued	2025
dc.identifier.uri	http://hdl.handle.net/10453/190533
dc.description	University of Technology Sydney. Institute for Sustainable Futures.	en_US.UTF-8
dc.description.abstract	Sanitation has been recognised as one of the greatest public health achievements of the last century. Yet in many low-income countries, inadequate sanitation still contributes to thousands of diarrhoeal deaths annually. While more people globally use an on-site sanitation system (OSS) rather than a sewer, there is limited understanding of OSS implementation and performance across different contexts. Unsafe management of OSSs can lead to the release of untreated excreta into the environment, exposing people to pathogens, particularly through surface waters and water supplies. This thesis examines health risks associated with OSSs in low- and middle-income countries (LMICs) from a public health engineering perspective. This research aims to enhance understanding of these risks through novel empirical studies on sanitation implementation and by identifying how monitoring data can better reflect health risks. The thesis by compilation includes four papers: a literature review on sanitation investment drivers, two empirical studies examining the relationship between OSS implementation and faecal contamination of drains and groundwater, and an investigation of indicators to better assess health risks beyond those monitored for the global sanitation target of safely managed sanitation. This research revealed that many OSSs fail to meet design, siting, or management standards and pose significant public health risks. Three-quarters of systems classified as ‘safely managed sanitation’ by global monitoring still present health risks to the users, public or workers. Many septic tanks discharge directly to drains and release numerous pathogens in high concentrations with little improvement over direct toilet discharge. The prevalence of hazards varied between and within countries and monitoring of key features of OSS implementation and the surrounding environmental context is necessary to identify and prioritise risks. Empirical data, including on pathogens, can improve understanding of how implementation influences risks and which failures or contamination pathways to prioritise. Improved implementation or alternative solutions are needed, particularly for effluent management and OSS in impermeable soils or shallow groundwater areas. Future research could replicate these methods at larger scales or different areas to validate findings across different contexts, address remaining gaps related to pathogen removal in OSS, and support translating these findings to practice. This thesis contributes new evidence on pathogens and health risks associated with OSSs and presents improved methods for monitoring these risks at various scales. This research can improve awareness of the multiple risks associated with OSSs and emphasises the importance of using local data to prioritise public health in sanitation investment decisions.	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/10453/190533/1/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	© 2025 Freya A. Mills
dc.rights	au.edu.uts.lib/cph
dc.title	Implementation And Monitoring Of On-Site Sanitation Systems To Mitigate Public Health Risks In Low-and Middle-Income Contexts	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*

Abstract:

Sanitation has been recognised as one of the greatest public health achievements of the last century. Yet in many low-income countries, inadequate sanitation still contributes to thousands of diarrhoeal deaths annually. While more people globally use an on-site sanitation system (OSS) rather than a sewer, there is limited understanding of OSS implementation and performance across different contexts. Unsafe management of OSSs can lead to the release of untreated excreta into the environment, exposing people to pathogens, particularly through surface waters and water supplies. This thesis examines health risks associated with OSSs in low- and middle-income countries (LMICs) from a public health engineering perspective. This research aims to enhance understanding of these risks through novel empirical studies on sanitation implementation and by identifying how monitoring data can better reflect health risks. The thesis by compilation includes four papers: a literature review on sanitation investment drivers, two empirical studies examining the relationship between OSS implementation and faecal contamination of drains and groundwater, and an investigation of indicators to better assess health risks beyond those monitored for the global sanitation target of safely managed sanitation. This research revealed that many OSSs fail to meet design, siting, or management standards and pose significant public health risks. Three-quarters of systems classified as ‘safely managed sanitation’ by global monitoring still present health risks to the users, public or workers. Many septic tanks discharge directly to drains and release numerous pathogens in high concentrations with little improvement over direct toilet discharge. The prevalence of hazards varied between and within countries and monitoring of key features of OSS implementation and the surrounding environmental context is necessary to identify and prioritise risks. Empirical data, including on pathogens, can improve understanding of how implementation influences risks and which failures or contamination pathways to prioritise. Improved implementation or alternative solutions are needed, particularly for effluent management and OSS in impermeable soils or shallow groundwater areas. Future research could replicate these methods at larger scales or different areas to validate findings across different contexts, address remaining gaps related to pathogen removal in OSS, and support translating these findings to practice. This thesis contributes new evidence on pathogens and health risks associated with OSSs and presents improved methods for monitoring these risks at various scales. This research can improve awareness of the multiple risks associated with OSSs and emphasises the importance of using local data to prioritise public health in sanitation investment decisions.

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