Project

Physiological properties of bacteria involved in biofouling

Production of sufficient clean water becomes more and
more difficult with the increasing numbers of human,
agricultural, and industrial users. In a lot of cases
sustainable use of clean groundwater is not possible
and surface water (sea, river) is used as an alternative
source for clean water production. Reverse osmosis is
a powerful technology to remove the large variety of
contaminants in surface water. However, the membranes
are susceptible to (bio-) fouling and need to be cleaned on
a regular basis. Secondly, (bio-)fouling results in a higher
energy consumption during the water production and a
shortening of the life-time of the membranes. Knowledge
of the processes involved in biofilm formation leads to
improved cleaning strategies. Control of biofilm formation
on membranes reduces the energy requirement and the
amount of cleaning cycles in order to produce clean and
safe water.

Figure 1: Scanning electron microscopy image of a biofouled RO membrane (5000X).
Figure 1: Scanning electron microscopy image of a biofouled RO membrane (5000X).

Technological challenge

A subpopulation of the bacteria that are present in the feedwater will attach to the surface of the membrane and spacers in spiral wound modules. After attachment they produce exopolysacharides resulting in a slimy layer that obstructs the feed channel and block the membrane (Figure 1).

The challenge in this project is to control the bacterial population, attachment and subsequent exopolysacharide formation.

Figure 2: Workflow molecular identification of microorganism.
Figure 2: Workflow molecular identification of microorganism.
Figure 3: Scanning confocal laser photomicrograph of bacterial biofilm assayed with Live/Dead staining.
Figure 3: Scanning confocal laser photomicrograph of bacterial biofilm assayed with Live/Dead staining.

Approach

Previously, Bereschenko et al identified several bacteria that were involved in initial bioflm formation and maturation (figure 2). The properties of these keyplayers will be determined and used to inhibit and/or remove biofouling. The effectiveness of cleaning procedures will be determined and optimized with biofilms from full scale installations and laboratory cultivated biofilms. The sensitivity and resistance of bacteria to chemical and physical treatment will be investigated with, among others, Live/Dead staining in combination with CSLM, SEM, and AFM (figure 3).

If you have any questions, or want to do a thesis / internship on this subject, please contact me. For thesis / internship subjects please go to link1 and link2.