Energy Generation:

Anaerobic digestion

  • Improved reactor design and operation for the anaerobic digestion of biowastes

    Improved reactor design and operation for the anaerobic digestion of biowastes

    Supervisor: Professor Mohamed Pourkashanian, Dr Kevin Hughes and Dr Davide Poggio

    Anaerobic digestion is usually carried out in single semi-continuous reactors, especially due to their simpler construction and operation. However, this simplicity implies relatively low conversion rates and productivities and, as a consequence, larger digester volumes are needed.

    This PhD project will look at possible strategies to develop a new generation of digesters, which can perform a faster and more compact conversion of biowastes. There are different approaches that will need to be explored and evaluated, which may modify both the design and the operation of the digester. Some examples are: biomimicry, model-based design of reactors, microaerobic conditions, staged and temperature phased digesters, use of activated or degradable carriers. The outcome of this first part of the project will be a set of design and operational recommendations that will be experimentally tested in a laboratory environment. A prototype will need to be built and its performance will be compared to existing CSTR reactors.

    The focus of the study will be on micro and small-scale digestion, where process intensification would result in comparatively high advantages. In this regard, the project benefits from existing collaborations with industrial partners and project developers, which can contribute both to the design phase and potential scale-up considerations.

  • Improved reactor design and operation for the anaerobic digestion of biowastes

    Power Generation in rural communities - Fully funded PhD Scholarship

    Supervisor: Professor Mohamed Pourkashanian

    For electrification projects to be successful, they must be suitable for the needs of the communities using them. Whilst electricity generation from some renewable sources is intermittent, hybrid solutions integrated with other forms of power generation and storage are able to provide reliable power, and can be optimised to a lower economic cost. There is also potential for smart grids and more adaptive local demand. Models and systems used for delivering energy to rural areas have been designed in industrialised countries, so there is uncertainty about how appropriate they are for developing countries. Areas where socio-technical nexus issues are particularly important include modelling load profiles, calculating willingness to pay and ongoing maintenance. This research will look at ways to evaluate microgrid systems and models, identifying how they can be improved by jointly considering social and technical aspects.

    The major current areas of research in the group include carbon capture technology from power generation, low emission CCGT technology, clean coal/biomass combustion technology, fuel cells, alternative aviation fuels, biogas from waste, etc.

    The successful applicant will receive appropriate training to work at the forefront of research in the relevant areas of research.

    The studentship will be available for a period of 3 years at the standard RCUK rate which covers UK/EU fees and includes a non-taxable stipend at the RCUK rate (£14,777 in 2018/2019) and a budget for IT equipment, books, software and travelling to conferences, and/or project meetings.

    Potential applicants should have, or are expecting to obtain in the near future, a first class honours degree in engineering, mathematics, or science. The studentship is open to UK/EU candidates only. The successful candidate should fulfil the eligibility criteria for EPSRC funding through UK/ EU nationality and residency status.

    The research work will be based in the Energy Engineering Group within the Department of Mechanical Engineering, which is a part of the Energy 2050 initiative within the University of Sheffield to develop world-leading activity in energy research. The student will be working within an exciting and dynamic group with approximately 40 PhD researchers and over 12 postdoctoral research fellows undertaking a broad area of energy research with strong links to industry.

    The Department of Mechanical Engineering has been a major discipline in the University since its foundation in 1905. The Research Excellence Framework (REF, December 2014) placed the Department within the Top 5 for Mechanical Engineering in the UK.

    For further information please contact Professor Derek B Ingham    phone: 0114 21 57215    email:

  • Improved reactor design and operation for the anaerobic digestion of biowastes

    Modelling, design and testing of integrated anaerobic digestion and hydroponics systems for closed-loop urban applications

    Supervisor: Professor Mohamed Pourkashanian, Dr Kevin Hughes and Dr Davide Poggio

    Anaerobic digestion (AD) will play a major role in the future circular economy, in particular enabling biological closed loops with complete recycling of nutrients and improved recovery of energy. An emerging opportunity in urban environments is the integration of organic wastes treatment through AD and the re-use of digestate and nutrients in soil-less agriculture such as hydroponics.

    This PhD project will look closer at these “waste to food” systems, and at the synergies that exist between the waste degradation and food production parts of the system. Activities will include the review of past attempts (e.g. the biological closed-loop for life support in space missions), the modelling of energy, water and nutrients flows and transformations in the different parts of the system, a model-based design and techno-economic evaluation of the system in different scenarios. Experimental tests may be conducted in laboratory environments, especially to evaluate the digestate-hydroponics interactions. The Energy 2050 group is currently collaborating with a successful micro-AD project in urban settings, and this will allow the student to be involved in a real case scenario.
  • Improved reactor design and operation for the anaerobic digestion of biowastes

    Development and validation of control strategies for flexible and demand-driven anaerobic digestion

    Supervisor: Professor Mohamed Pourkashanian, Dr Kevin Hughes and Dr Davide Poggio

    Bioenergy and anaerobic digestion can have a major role as a source of dispatchable energy in future energy systems with high penetration of intermittent renewables. The Energy 2050 group is involved in different research projects where a flexible operation of anaerobic digestion leads to an improved economy of the whole system. Examples of these projects are the provision of heat to autonomous desalination systems, the stabilisation of micro-grids in rural electrification projects, and the biomethanation of hydrogen from grid excess electricity (power to methane).

    In all these scenarios an improved control of AD is necessary, which is able to match the biogas demand of the system while maintaining process stability. This project will involve the review of existing control strategies for AD, the use of process modelling to evaluate and benchmark the most appropriate control strategies for different demand-driven scenarios, and the experimental validation of the control strategies at laboratory scale.

  • Improved reactor design and operation for the anaerobic digestion of biowastes

    Optimising anaerobic co-digestion: improving the outputs and stability of anaerobic processes

    Supervisor: Professor Mohamed Pourkashanian, Dr Kevin Hughes and Dr Davide Poggio

    Anaerobic co-digestion consists of the anaerobic digestion (AD) of a mixture of two or more substrates with complementary characteristics, so that biogas production, digestate characteristics and process stability are enhanced through their joint treatment. The Energy 2050 group is researching co-digestion for different scenarios, such as the digestion of energy-rich substrates to boost biogas productions in demand driven applications, or to improve the degradation of agricultural by-crops in rural digesters in developing countries.

    This PhD project will systematically research the possible synergistic effects of co-digestion. These include the enhancement of organic matter decomposition due to the addition of easily degradable substrates (priming effect), the increased buffering capacity, the reduction of inhibitory causes, the provision of balanced micro and macro nutrients, the role of fibers as carriers of micro-organisms, the provision of optimal water content, etc. Modelling will be used to describe mechanistic interactions and design co-digestion strategies in different scenarios, which will be tested and validated with laboratory scale reactors.