Bacterial Growth Potential of Antiscalants used in Reverse Osmosis Systems using Seawater Autochthonous Microbial Communities
Embargo End Date2023-07-02
AuthorsHasanin, Ghadeer Abdullah
AdvisorsVrouwenvelder, Johannes S.
Committee MembersMerzaban, Jasmeen
Gil, Graciela Gonzalez
KAUST DepartmentBiological and Environmental Science and Engineering (BESE) Division
Access RestrictionsAt the time of archiving, the student author of this thesis opted to temporarily restrict access to it. The full text of this thesis will become available to the public after the expiration of the embargo on 2023-07-02.
AbstractAntiscalants are chemicals used in membrane-based water desalination processes to prevent the scaling of salts on the membrane. Previous studies suggested that antiscalants could lead or contribute biological fouling by providing growth-promoting factors such as source of biodegradable carbon or phosphorus. However, the test in previous studies were conducted using drinking water and pure cultures of bacteria isolated from freshwater. These conditions do not reflect those of desalination systems.
In this study, we determined the microbial growth potential of eight antiscalants under conditions relevant to desalination plants. To this end, autochthonous microbial communities from the Red Sea were used, and we exposed them to chemically diverse antiscalants.
The chemical characterization of the antiscalants showed that their carbon content ranged from 0.02 to 0.15 mg C/ mg antiscalant. Fourier transform infrared and nuclear magnetic resonance spectroscopy allowed us to classify the eight tested antiscalants into three types based on their chemical structure. These types were phosphonate-based, natural inulin-based, and polyacrylate-based antiscalants.
The growth potential of the antiscalants was determined by incubating seawater with antiscalants (50 mg/L) and an initial bacterial cell content of 20,000 cells/ml at 30