PhD scholarship on water quality in recirculating aquaculture systems and its relationship with feed composition

Wednesday 06 May 20

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The National Institute of Aquatic Resources (DTU Aqua) at the Technical University of Denmark (DTU) invites applications for a 3-year PhD position within the topic “Water quality in RAS and its relationship with feed composition”. The starting date is August 15, 2020 or according to mutual agreement. The successful candidate will be employed at the Section for Aquaculture located in Hirtshals in the Northern part of Denmark. Here, we perform research on sustainable farming technology, recirculation, water quality, environmental footprint, as well as research on fish nutrition, welfare, and physiology.


We aim to contribute to a continued development of rearing systems and methods that ensure cost-efficient fish production with minimum environmental impact in both freshwater and saltwater systems. To achieve this, our research within farming technology covers recirculation systems, biofiltration, chemical and microbial water quality issues, waste treatment, and reduced environmental impact. Our research within fish feed bridges between water quality and fish nutrition. We study amino acid and protein requirements, digestion, and nutrient utilization including effects of transitioning to alternative raw materials. Research in metabolism and stress physiology in fish involves nutrition, water quality, and general husbandry conditions.


Recirculating Aquaculture Systems (RAS) provide the means for a sustainable and resilient aquaculture production. Resilience and thereby economic performance of RAS rely on good and stable water quality. To improve RAS performance, the dependency of chemical and, in particular, microbial water quality on operation procedures and feed composition needs to be explored in more details.

Depending on the recirculation intensity, feed is the primary source of nutrients and organic matter in RAS. Feed fractions that are not utilized by the fish end up as waste (dissolved or particulate) in the system, where they can serve as substrates for bacteria. The composition of the feed is thus expected to be of important for internal RAS water quality as well as effluent water quality.


In this PhD, the relationship between feed composition and microbial and chemical water quality in RAS will be investigated, possibly covering also the effects of/on fish and fish gut microbiota. New and innovative water quality evaluation methods such as microbial activity measurements, particle size distribution, flow-cytometry, and molecular microbiological applications (qPCR, high throughput sequencing) will be applied in addition to traditional water quality parameters.

Responsibilities and tasks

You will be involved in a collaborative research project involving DTU Aqua colleges and several European research institutions. Your main role will be to design and conduct research on the topic in our facilities. This involves practical experiments in lab-scale RAS, as well as laboratory analysis and studies aimed to improve the understanding on the factors influencing microbiota and microbial water quality in RAS. In addition to conducting research of your own, you will participate in other ongoing related research activities in the Section for Aquaculture.


Candidates should have a two-year master's degree (120 ECTS points) or a similar degree with an academic level equivalent to a two-year master's degree. Ideally you have a degree in Biology, Engineering, Aquatic Science & Technology or the like with a specialization in aquaculture, water treatment, microbiology or similar.

Our ideal candidate

  • Possesses scientific curiosity and is eager to test hypotheses to advance current knowledge
  • Has previous experience in experimental work with fish and/or water quality
  • Has a strong interest in microbiology and water quality in aquaculture
  • Is interested in RAS and practical application of the results achieved
  • Has a keen interest in laboratory analysis
  • Shows proficiency in written and spoken English, and a determination for disseminating your work

Approval and Enrolment
The PhD scholarship is subject to academic approval, and the candidate will be enrolled in one of the general PhD degree programs at DTU. For information about our enrolment requirements and the general planning of the PhD study program, please see the DTU PhD Guide.


An assessment of the applicants will be made by Head of Section Per Bovbjerg Pedersen, Senior researcher Anne Johanne Tang Dalsgaard, and Researcher Sanni-Leea Aalto.

We offer
DTU is a leading technical university globally recognized for the excellence of its research, education, innovation and scientific advice. We offer a rewarding and challenging job in an international environment. We strive for academic excellence in an environment characterized by collegial respect and academic freedom tempered by responsibility.

Salary and appointment terms
The appointment will be based on the collective agreement with the Danish Confederation of Professional Associations. The allowance will be agreed upon with the relevant union. The period of employment is 3 years.


Please note that place of employment will be at the research facilities of DTU Aqua in Hirtshals, Denmark.


You can read more about career paths at DTU here.


Further information
Further information may be obtained from Head of Section Per Bovbjerg Pedersen, tel.: +45 21314780 mail:

You can read more about DTU Aqua at

Please submit your online application no later than 15 June 2020 (23:59 local time).


Applications must be submitted as one PDF file containing all materials to be given consideration. To apply, please open the link "Apply online", fill out the online application form, and attach all your materials in English in one PDF fileThe file must include:

  • A letter motivating the application (cover letter)
  • Curriculum vitae
  • Grade transcripts and BSc/MSc diploma
  • Excel sheet with translation of grades to the Danish grading system (see guidelines and Excel spreadsheet here)

Candidates may apply prior to obtaining their master's degree but cannot begin before having received it.


Applications and enclosures received after the deadline will not be considered.

All interested candidates irrespective of age, gender, race, disability, religion or ethnic background are encouraged to apply.


As a leading international institute for marine sciences, fisheries and aquaculture, the goal of DTU Aqua's research is to address the environmental consequences and interactions of human activities in the aquatic environment and help resolve the longstanding conflict between aquatic resource exploitation and conservation.


Technology for people
DTU develops technology for people. With our international elite research and study programs, we are helping to create a better world and to solve the global challenges formulated in the UN’s 17 Sustainable Development Goals. Hans Christian Ørsted founded DTU in 1829 with a clear vision to develop and create value using science and engineering to benefit society. That vision lives on today. DTU has 11,500 students and 6,000 employees. We work in an international atmosphere and have an inclusive, evolving, and informal working environment. Our main campus is in Kgs. Lyngby north of Copenhagen and we have campuses in Roskilde and Ballerup and in Sisimiut in Greenland.