We are advertising for a 4 year PhD studentship “Sewage-sludge biochar for resource recovery: A circular and low carbon solution for wastewater treatment plants”, fully funded by the Scottish Government’s Hydro Nation Scholars Programme. The project is open to students worldwide. The supervisory team includes Dr Szabolcs Pap (ERI), Dr Mark Taggart (ERI), Dr Tamsyn Kennedy (Scottish Water), and Dr Boris Agarski (University of Novi Sad).
Deadline: Wednesday January 10, 2024
How to apply: Applicants must send a completed Hydro Nation Scholarship application form, cover letter and their Curriculum Vitae to Dr Szabolcs Pap (szabolcs.pap@uhi.ac.uk) by the final submission deadline of 10th January 2024.
Applicants are strongly advised to make an informal enquiry about the PhD to the primary supervisor well before the final submission deadline.
Project Background
As we transition from a fossil fuel-based world to a net-zero and bio-based economy, we must move towards more sustainable resource management. In Scotland, current options to dispose of sewage sludge (SS) are very limited, with disposal to land increasingly considered unsustainable given the potential presence of recalcitrant chemical contaminants (organic/inorganic), microplastics, antimicrobial resistant (AMR) bacteria, etc., which may in turn threaten the wider environment. However, this waste may be considered a resource with significant potential to be repurposed. In parallel, we also urgently need to close the terrestrial phosphorus (P) cycle, as it is well recognised that P is an essential resource for agriculture (and other industries), but there is now pressing concern over its future availability (as a finite, mined global terrestrial resource). One potential coupled solution to address both challenges is biochar. This project will explore the potential of granular biochar, generated from SS, to be used to remove excess P from wastewater (through adsorption) and in doing so create a ‘new’ solid material that could be used on land as a carbon (C) and P rich soil amendment or a platform for extractable/recoverable P.
Biochar is a pyrogenic carbon-rich material produced from waste biomass (here SS) through pyrolysis under oxygen-limited conditions. The production of biochar from SS would transform a widespread waste bioresource (resultant from most large wastewater treatment plants (WWTPs) globally) into a ‘new’ material – which could then be utilised in novel ways. Producing biochar itself would also serve multiple aims, including solid waste repurposing, reducing carbon emissions (through creation of a stable form of solid C) and pollutant reduction – as biochar creation will (through thermal degradation) eliminate many organic pollutants now present in SS. Additionally, eutrophication driven by P-rich wastewater threatens freshwater worldwide. WWTPs are required to remove P from their influents as there are strict limits for P release into lakes/rivers/seas. Hence, P ‘extraction’ from P-rich wastewater and/or subsequently from saturated P-rich biochar could both minimise eutrophication and recapture a valuable P resource that can then be re-used on land.
However, multiple questions remain ‘if’ such a circular process were to be realised – not least regarding technical feasibility and the environmental safety of applying SS biochar to reduce wastewater P and then the use of such material on land as a C rich P-laden soil amendment. Given rapid advances in biochar science and technology in recent years, together with a growing biochar market (i.e., its inclusion in the new EU Fertilising Product Regulations as a marketable product from July 2022), this proposal has the potential to inform a step-change in SS handling and biochar production/use within the Scottish wastewater and agricultural sectors.
The student will address the following research objectives:
- Laboratory based batch and dynamic experiments with SS biochar (raw or thermochemically modified) to demonstrate P removal/recovery from model solutions and ‘real’ wastewaters.
- Implementation of SS biochar into the FiltraFlo-P pilot-scale P recovery unit (owned by ERI) to show a ‘proof of concept’ in a relevant environment; specifically at the Scottish Water Horizon (SWH) Wastewater Development Centre in Bo’ness.
- Characterisation (using chemical extraction) of ‘plant available’ P in biochar and plant-based pot trials to consider its potential uptake/benefit if used in a soil environment.
- Evaluation of the cost effectiveness of SS biochar as a water treatment tool – assessment of biochar’s environmental impact using life-cycle assessment (LCA) and the economic potential for scale-up and future use, including energy/carbon budgets.
The student will be based at the Environmental Research Institute, UHI North, West and Hebrides, University of the Highlands and Islands in Thurso, Northern Scotland. The student will gain skills in environmental chemistry/engineering, environmental modelling and material science and will benefit from access to a wide range of instrumental facilities available at the Environmental Research Institute and a fully equipped “LCA Center and the Laboratory for Environmental Engineering” at the University of Novi Sad, Serbia.
Funding Notes
The Hydro Nation Scholars Programme is an open competition for PhD Scholars to undertake approved projects, hosted within Scottish Universities and Research Institutes. Full funding is available from the Scottish Government (to host institutions via the Scottish Funding Council). The funding available will be in line with the UKRI doctoral stipend levels and indicative fees. Applicants should have a first-class honours degree in a relevant subject or a 2.1 honours degree plus Masters (or equivalent). Shortlisted candidates will be interviewed on the 7th or 8th of February 2024.
This project is also advertised on FindAPhD
