PhD project: Anaerobic digestion of FOGs with as pre-treatments to improve biodegradation: Ireland

FOG (fat, oil and grease) is a term frequently used to define the layer of lipid-rich material that can be separated from wastewaters such as the ones resulting from food processing. Currently, most of the collected FOGs are mixed with other secondary sludges and disposed in landfill or land applied. However, FOGs have a high energy content, which would make it perfect candidates as substrates for energy production, in the form of biogas, through anaerobic digestion. Anaerobic digestion is an efficient and widely used process to treat wastes and sewage sludge, where the mixed microbial community combines organic matter degradation with biogas production through different metabolic steps. Despite its energy potential, the long aliphatic carboxylic chains of FOGs are difficult to be hydrolysed, and hydrolysis of this compounds is, in general, the limiting step of the anaerobic treatment of these waste products. For this reason, FOGs rich substrates can be preliminary pre-treated in order to improve the breakage of the carboxylic chains and facilitate the microbial hydrolysis, minimizing also the formation of LCFA during the successive anaerobic digestion step. Among the possible pre-treatments, thermal hydrolysis applies high temperature and pressure to intensify FOGs disintegration, while high frequency ultrasounds can break complex macromolecules by generating OH radicals via sonolysis.

We seek for highly motivated candidates to enrol a PhD project with the main objectives:

  1. study the feasibility of ambient temperature anaerobic digestion to treat FOGs after pre-treatment;
  2. process optimization;
  3. understanding the influence of long carboxylic chains on the microbial community dynamics during the process.

Applications are invited from graduates with at least a 2.1 BSc or masters biology, microbiology, or a related field. Fluency in English is a requirement. Prior experience with reactor’s operation would be an advantage. The project will be undertaken in conjunction with the National University of Ireland, Galway (Ireland; Dr Lara Paulo and Prof. Vincent O’Flaherty), the Dairy processing Technology centre (Ireland), Wetsus Institute (The Netherlands; Dr M. Cristina Gagliano), Instituto de Ricerca sulle Acque (IRSA, Italy; Dr. Camilla Braguglia). The student will be largely based in NUI Galway, with possible secondment at WETSUS Institute (The Netherlands) or IRSA (Italy). The work builds build on collaboration between the University, Wetsus and the IRSA. The successful applicant will register in the NUI, Galway School of Natural Sciences Structured PhD Programme.

For further details please contact Dr. Lara Paulo (, Dr. Cristina Gagliano ( or Prof. Vincent O’Flaherty (

Applications (e-mail only) by sending a CV and cover letter to: Prof. Vincent O’Flaherty (, Microbiology, NUI, Galway. Please use as email title ‘’Application to PhD in AD of FOGs’’.

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