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Separation of chemicals obtained from the anaerobic fermentation of organic waste

   School of Engineering

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  Dr D Dionisi, Dr A Majumder  Applications accepted all year round  Self-Funded PhD Students Only

About the Project

This project, which includes both computer simulation and experimental investigation, is aimed at the optimisation of distillation conditions for the separation of diluted aqueous mixtures of ethanol and volatile fatty acids (VFA’s), mainly acetic acid and butyric acid. These chemicals are essential in our everyday life and are currently produced in millions of tonnes per year. E.g. ethanol is mainly used as renewable fuel, as an alternative to conventional petrol, while acetic acid is used as an intermediate in the chemical industry for the productions of plastics, paints etc.

The problem is that the current production processes used to manufacture these chemicals raise many doubts about their sustainability and environmental impact. E.g acetic acid is produced from natural gas, a non-renewable fossil fuel, using a high-pressure and high-temperature process, in the presence of heavy metals as catalysts.

As an alternative to the current processes, these chemicals can also be produced by the anaerobic fermentation of organic waste, e.g. municipal solid waste, farm waste, forestry residues and many others. Although anaerobic fermentation of organic waste would be a much more sustainable and environmentally friendly process, one of the main problems that prevents its use for the production of these chemicals at commercial scale is the separation of the chemicals from water after the fermentation process.

Therefore, this project is aimed at the simulation and experimental investigation of the distillation of diluted aqueous solutions of ethanol and VFA’s in order to determine the following:

- the effect of feed concentration and pH on the number of stages and energy requirements of the distillation column(s);
- the effect of the operating parameters of the distillation, e.g. reflux ratio, column pressure, feed location, on the separation efficiency;
- the design of the optimum sequence of distillation columns for the separation of the fermentation products.

The successful candidate should have, or expect to have, an Honours Degree at 2.1 or above (or equivalent) in Chemical Engineering.

Essential background: Chemical Engineering

Knowledge of: Interest in separation, distillation, simulation software and in doing experimental work

Funding Notes

This project is for self-funded students only. There is no funding attached to this project. The successful applicant will be expected to pay Tuition Fees and living expenses, from their own resources, for the duration of study.


Dionisi, D. & Silva, IMO. (2016). 'Production of ethanol, organic acids and hydrogen: an opportunity for mixed culture biotechnology?'. Reviews in Environmental Science and Biotechnology, vol 15, no. 2, pp. 213-242. DOI: 10.1007/S11157-016-9393-Y


This project is advertised in relation to the research areas of the discipline of Chemical Engineering.

Formal applications can be completed online: You should apply for Degree of Doctor of Philosophy in Engineering, to ensure that your application is passed to the correct College for processing.

NOTE CLEARLY THE NAME OF THE SUPERVISOR AND EXACT PROJECT TITLE YOU WISH TO BE CONSIDERED FOR ON THE APPLICATION FORM. Applicants are limited to applying for a maximum of 2 projects. Any further applications received will be automatically withdrawn.

Informal inquiries can be made to Dr D Dionisi ( with a copy of your curriculum vitae and cover letter. All general enquiries should be directed to the Graduate School Admissions Unit (
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