Enhancing the formation and shear resistance of nitrifying biofilms on membranes by surface modification.
Polypropylene (PP) membranes and polyethylene (PE) surfaces were modified to enhance formation and shear resistance of nitrifying biofilms for wastewater treatment applications. A combination of plasma polymerization and wet chemistry was employed to ultimately introduce poly(ethyleneglycol) (PEG) chains with two different functional groups (-PEG-NH(2) and -PEG-CH(3)). Biofilm growth experiments using a mixed nitrifying bacterial culture revealed that the specific combination of PEG chains with amino groups resulted in most biofilm formation on both PP and PE samples. Detachment experiments showed similar trends: biofilms on -PEG-NH(2) modified surfaces were much stronger compared to the other modifications and the unmodified reference surfaces. Electrostatic interactions between the protonated amino group and negatively charged bacteria as well as PEG chain density which can affect the surface structure might be possible explanations of the superiority of the -PEG-NH(2) modification. The success of the-PEG-NH(2) modification was independent of the original surface and might, therefore, be used in wastewater treatment bioreactors to improve reactor performance by making biofilm formation more stable and predictable.
Lackner
Susanne
S
Department of Environmental Engineering, Technical University of Denmark, Miljoevej, Bldg. 113, 2800 Lyngby, Denmark. sul@env.dtu.dk
Holmberg
Maria
M
Terada
Akihiko
A
Kingshott
Peter
P
Smets
Barth F
BF
D001419:Bacteria / Q000166:cytology; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D008567:Membranes, Artificial; D018613:Microscopy, Confocal; D009584:Nitrogen / Q000378:metabolism*; D020959:Polyethylene / Q000737:chemistry; D011126:Polypropylenes / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D013314:Stress, Mechanical; D013499:Surface Properties
D001426:Bacterial Proteins; D008567:Membranes, Artificial; D011126:Polypropylenes; D020959:Polyethylene; D009584:Nitrogen