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Maximising resource recovery from wastewater sludge – developing biorefineries PhD


   School of Water, Energy and Environment (SWEE)


About the Project

This prestigious EPSRC Doctoral Training Partnership award, co-funded by the industrial partner Severn Trent Water, provides a three-year fully-funded PhD studentship. The successful candidate will work within a multi-disciplinary team, supported by both academic and industry supervisors, on innovative solutions to maximise resource recovery from wastewater sludge treatment. The project addresses the industry ambition to convert sludge treatment centres into biorefineries, where the focus is on maximising renewable energy formation and product recovery.

Wastewater treatment is transitioning from a linear vision where wastewater and sludges are treated and discharged, to a circular economy vision where we aim to maximise resource recovery. The water sector currently recovers renewable energy, heat and organic fertilizers from sludges, with anaerobic digestion as the core technology enabling this sustainable treatment. Sludge treatment centres are designed to treat a typical ratio of 40:60% surplus activated sludge (SAS) and primary sludge (PS), while projected innovations and tighter permits implemented in wastewater treatment will result in changes in the nature and volumes of the sludge generated. To illustrate, future wastewater quality programmes are likely to increase the volumes of SAS generated, as a result of new activated sludge processes (ASPs) or chemical dosing schemes to meet tighter nutrient permits. Contrarily, innovations like cellulose recovery or enhanced primary wastewater treatment are focussed on early solids removal, hence resulting in reduced SAS volumes. This project will investigate how changes and innovations in wastewater treatment will impact the ability of the water industry to extract resources from wastewater sludges, and explore innovative treatment options that can future proof sludge treatment centres and enable their transition to biorefineries.

This PhD project will address the following research objectives: 

  1. Identify the main changes and innovations in wastewater treatment that will impact the nature and volumes of sludges generated on site; and the predicted impact on current resource recovery technologies (i.e. anaerobic digestion). 
  2. Characterisation of PS and SAS by sampling in full-scale sludge treatment centres, while capturing relevant process information influencing sludge properties. 
  3. Experimentally evaluate the anaerobic digestibility of sludge with varying SAS to PS ratios and propose optimisation strategies to sustain renewable energy generation. 
  4. Investigate alternative treatment options, such as fermentation, that can transition sludge treatment centres to biorefineries, considering associated value recovery routes and energy vectors for the sector.

Cranfield University is a unique learning environment with world-class programmes, unrivalled facilities and close links with business, industry and governments, all combining to attract the best students and teaching staff from around the world. In the last Research Excellence Framework (REF) assessment, 81% of research at Cranfield was rated as world-leading or internationally excellent.

Severn Trent Water (STW) is one of the largest regulated water and wastewater businesses in England and Wales providing services to more than 4.5 million households and businesses. They are a national leader in university / industry collaboration with a well-established, productive research relationship with Cranfield University.

This project delivers against the strategic needs in the area of bioresources of one of the UK’s major water utilities, with support from stakeholders from Severn Trent’s Innovation and Bioresources teams. The student will have industrial exposure and become a member of Severn Trent’s Bioresources community of practice, where he/she will be exposed to stakeholders from across the business and deliver regular updates on project findings. He/she will gain industrial experience, learning about current sludge management and treatment practices and cutting-edge innovations proposed to transition sludge treatment centres to biorefineries.

The successful candidate will have the opportunity to work alongside the industry sponsor and gain significant experience in industrial research and development. It is expected that the candidate will attend and present at national and international conferences.

This is an applied PhD, with the student having regular interaction with Severn Trent Water and being exposed to state-of-the-art industrial practices in wastewater and sludge treatment; all providing a unique learning experience and opportunities for further employability. The candidate will receive academic technical training including designing and operating bioreactors and learning state of the art analytical skills.

Entry requirements

Applicants should have a first or second class UK honours degree or equivalent in a related discipline. This project would suit an applicant with a strong interest on environmental engineering, environmental sciences, resource recovery and development of sustainable treatment solutions, who is keen on industry-academic collaboration and on applied research. Applicants with a background on biology, chemistry, engineering, water science or environmental science will be particularly well suited for this project.

Our Values 

Our shared, stated values help to define who we are and underpin everything we do: Ambition; Impact; Respect; and Community. Find out more here. We aim to create and maintain a culture in which everyone can work and study together and realise their full potential. 

Diversity and Inclusion

As an inclusive and diverse doctoral centre, we welcome applications from all highly motivated individuals, regardless of background, identity or disability.

Cranfield Doctoral Network

Research students at Cranfield benefit from being part of a dynamic, focused and professional study environment and all become valued members of the Cranfield Doctoral Network. This network brings together both research students and staff, providing a platform for our researchers to share ideas and collaborate in a multi-disciplinary environment. It aims to encourage an effective and vibrant research culture, founded upon the diversity of activities and knowledge. A tailored programme of seminars and events, alongside our Doctoral Researchers Core Development programme (transferable skills training), provide those studying a research degree with a wealth of social and networking opportunities.

How to apply

For further information please contact: 

Name: Dr Yadira Bajon Fernandez

Email: 

If you are eligible to apply for the PhD, please complete the online PhD application form stating the reference No. SWEE0207.


Funding Notes

Sponsored by the EPSRC, Severn Trent Water and Cranfield University, this Doctoral Training Partnership studentship will provide a bursary of up to £18,000 (tax-free) plus UK Home student fees for three years.

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