7.5 Pipes materials in drinking water distribution systems and their influence on bioadhesion, biofilm growth and detachment
Safety and security are two important features of drinking water distribution systems (DWDS) worldwide, that are often compromised by a suite of physical, chemical and microbiological factors adversely impacting quality of potable water reaching consumer taps.
Among the microbiological factors, more than 90% of microorganisms within the DWDS can be found in matrix-enclosed microbial communities, growing attached to pipe walls, called biofilms. Biofilm formation (and often its detachment in the water stream) poses a significant problem to the distribution network conditions by affecting the taste and odor of drinking water and promoting the corrosion of pipes. Moreover, DWDS harbor biofilms even in the presence of disinfectants, thus are a potential source of bacterial contamination and a major-health treat when pathogens are present.
Biofilms formation is a multi-stage process resulting from the balance of several factors. For this reason, the management of the persistent biofilm growth in DWDS requires an integrated approach and no single practice thus far appears to be sufficiently effective.
Among the several biofilm influencing factors investigated so far in DWDS applied research, the effect of pipe materials on biofilm formation is one of the most interesting. Corrosion-prone materials such as iron should be avoided due to the growth-promoting effects of the corrosion products, while polymeric pipes, despite known to restrict biofilm development, in some practice cases can support microbial growth. Overall, the scientific results are often contradictory and an effective solution for the current issues is still not found.
Thus, the right choice of pipe material would mean a first step towards a better management of biofilm development in DWDS, and further research is needed to better address the issue.
The basic idea of the project is to shape a new research approach taking into account the countless studies carried out in the last decades in the applied microbiology and biomedical engineering fields, which have elucidated the influence of the material surface characteristics on the microbial attachment and biofilm formation.
A multi-level research approach will concomitantly evaluate the influence of currently used materials on biofilm attachment and detachment and compared with new materials, which were already successfully applied to inhibit biofilm formation in other application fields.
This will be evaluated through a lab-scale simulator setup which will test the biofilm growth in parallel on different materials by re-creating the DWDS water characteristics and hydrodynamic conditions. Besides the design and control of this lab-scale process, a proper biofilm characterization will be a fundamental part of the project and will be carried out by the combination of methods in the field of physics and applied microscopy.
With the help of the already existing wealth of experience within the project partners and the Wetsus research team, the objective is to establish fundamental as well as engineering principles to ensure a consistent advance in the field.
The challenge is to develop a novel cheap and health-safe strategy to inhibit or avoid biofilms in the DWDS that is meaningful for practical implementations. The final aim is to translate theoretical perspectives into potential innovations in the materials to inhibit biofilm formation that are intended to be applied within the DWDS.
The qualifying candidate has an MSc degree in biotechnology or chemical and/or environmental engineering, with an aptitude in applied microbiology, chemistry and bioprocess engineering, alongside skills with principles of testing through practical laboratory experiments.
Development of process monitoring and control strategies will require furthermore a potential interest in physics, fluorescence microscopy and biofilms characterization.
The ideal candidate will have a strong motivation to work in a multidisciplinary environment and to develop new skills by learning from all the disciplines.
This project falls under the Wetsus research theme Biofilms. The theme stakeholders are: WLN (https://wln.nl/en/), Pentair (https://www.pentair.com/) and Vitens (https://www.vitens.com/organisation).
Promotor: Prof. Dr. Henny van der Mei (Dep. of Biomedical Engineering, University of Groningen)
Wetsus supervisor: Dr. M. Cristina Gagliano (contact information firstname.lastname@example.org)
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Wetsus, Leeuwarden, the Netherlands