(2025-OU9) Pushed to the Extreme: Extremophile-Mediated Bioremediation of Smouldering Sewage Sludge Emissions

Breakthrough multidisciplinary innovations are needed to achieve improved environmental sustainability and carbon neutrality within a safe, circular economy. Applied smouldering combustion has been shown as a novel environmental technology to economically treat challenging wastes with minimal energy footprints and limited infrastructure that otherwise pose environmental pollution risks – such as sewage sludge contaminated with per- and polyfluoroalkyl substances. However, the gas emissions from these systems are challenging to treat and often governs the operating costs and sustainability drawbacks. Smouldering emissions often contain CO2, CO, and H2O along with a complex mixture of unburned hydrocarbons (including acids, phenols, steroids, amides, sugars) and CH4 and H2 under certain smouldering conditions. However, smouldering emissions are notoriously poorly understood.  

In a separate discipline, astrobiology research seeking to define the limits of life has uncovered various extremophiles (i.e., organisms adapted to physical or chemical extremes) that are able to thrive in hostile environments. These extremophiles often possess unique adaptations not seen in other environments, including tolerance and metabolism of heavy metals and volatile compounds with antimicrobial properties. One unexplored pathway is using the waste smouldering emissions as a useful feedstock, to promote the selection of these extremophiles in this context, as opposed to a sustainability liability. These extremophiles could also be investigated for biomining of valuable compounds from the smoulder ash, enhancing the efficacy of the smouldering approach. 

This studentship will explore the combination of smouldering and extremophile waste treatment to ameliorate emissions from smouldering technologies. Together, this combination of technologies underpins a new circular economy approach to minimise environmental pollution and enhance the sustainability of waste treatment. The project will involve: (i) exploring how smouldering emissions vary with treatment regime, (ii) identifying extremophiles that metabolise smouldering emissions and smouldering ash, (iii) exploring how these microbial communities evolve with varying emissions and concentration profiles. 

Project highlights

• Integrating biological and thermochemical methods to reduce pollution  
• An placement with a world-leading national laboratory in Montréal Canada, with National Research Council Canada (NRC); 
• Training in state-of-the-art techniques across the fields of microbiology, chemistry, and environmental technology 

Methodology

A combination of chemistry, microbiological, and smouldering techniques will be applied to investigate the pathways to treat sewage waste. Standard smouldering experiments will be performed to capture emissions needed for the microbiological investigations. The microbiology experiments will identify and isolate keystones species in the community (e.g., smouldering-gas utilisers, contaminant degraders, and small organic molecule producers). Detailed analytical chemical techniques – such as GC-MS, HPLC-MS, in-situ IR, and flow photospectroscopies – will be used to track the fate of organic contaminants. The student will have access to a range of additional techniques at the partner organisations that can be used to identify microbial interactions.  

Training and skills

DRs will be awarded CENTA Training Credits (CTCs) for participation in CENTA-provided and ‘free choice’ external training. One CTC can be earned per 3 hours training, and DRs must accrue 100 CTCs across the three and a half years of their PhD.  

The student will be trained in specific laboratory-based techniques in organic chemistry characterisation, molecular biology (e.g., DNA extraction, PCR, library preparation, and DNA sequencing), applied smouldering, analytical geochemistry, and culture-based microbiology by members of the research team. A placement with NRC will enable participation in microbiological research at a top international research institute in Canada. The student will also be trained in computer-based techniques, including bioinformatic analysis of sequencing data and smouldering data analysis. The student will benefit from additional skills development opportunities offered by The Open University, e.g., communication skills, time management, and academic writing. 

Partners and collaboration

Fabrice Tanguay-Rioux (National Research Council Canada, NRC) is an environmental technology research officer, specialising in pairing microbial treatments alongside thermochemical processes. The NRC has a world-class research environment that explores both fundamental and practical aspects of this novel pairing of processes and includes specialised facilities to allow scale-up studies up to commercial sizes. 

Megan Barnett is a microbiologist specialising in the role of microbes in weathering and rare earth element cycling and developing techniques for microbial detection and study. Their expertise will support this project enhancing our understanding of microbial life in extreme environments. 

Further details

For any enquiries related to this project please contact Michael Macey, [Email Address Removed].  

For additional details please the following profile pages: 

• Michael Macey: https://www.open.ac.uk/people/mm34528 
• Tarek Rashwan: https://www.open.ac.uk/people/tr829  
• Daniel Payne: https://www.open.ac.uk/research/people/dtp65  
• OU Astrobiology: https://www5.open.ac.uk/research-groups/astrobiology/  

To apply to this project:  

• You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2025.  
• You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities.  
• Your application materials, including the CENTA Studentship Application Form 2025, your CV and the Open University application form must be emailed to [Email Address Removed]. Instructions on how to apply to the Open University are to be found on https://www5.open.ac.uk/stem/environment-earth-ecosystem-sciences/research/phd-students/current-opportunities-and-how-apply, please ensure you read this webpage before applying as you will need to obtain the relevant OU application form from here. Please quote CENTA 2025-OU9 when completing the application form. 

 Applications must be submitted by 23:59 GMT on Wednesday 8th January 2025.