Bacterial Adhesion and Fouling of Reverse Osmosis Membranes

Abstract

Adhesion of selected bacteria to cellulose actetate (CA) reverse osmosis (RO) membranes used in wastewater reclamation processes was investigated to determine its role in membrane fouling and reduced process efficiency. Adhesion of a hfycohcterium sp. previously isolated from an early stage of RO membrane biofouling was relatively unaffected by large variations in the ionic strength or pH of the buffer system. However, trace quantities of a polyoxyethylene ether nonionic detergent almost completely inhibited attachment. The mycobacteria were found to adhere to the CA membrane surface (or to a CA-affinity column) approximately 2.5fold more effectively than a wild-type strain of Escherichia coli The ability of Mycobucterium and E. coli to adhere to the membrane was correlated with their relative surface hydrophobicities as determined by their affinities for n-hexadecane. A similar correlation was established between a hydrophilic wild-type strain of Acinetobactev phos&devorus containing a single 17.8 mega-Dalton plasmid (PYGl) and a more hydrophobic isogenic derivative strain (P7P-) lacking the PYGl plasmid. Unlike the P7WT parent strain, the P7P-derivative produced more fimbrialike appendages, which may account for its enhanced hydrophobic and adhesive properties. The results suggest that hydrophobic interactions between bacterial cell surface components and the CA membrane surface play an important role in the initial stages of bacterial adhesion and RO membrane biofilm formation. JULY 1985 H.F. RIDGWAY ET AL 99

Modeling biocide action against biofilms

“…Note that Lf is in the denominator of H in Equation (27). If the initial biofilm thickness is large, then H is small, and correspondingly, LMV is small, in agreement with Figure 7.…”

“…The correlation coefficient is 0.996 between the LMV predicted by Equation (27) and the computer model simulated LMV. …”

“…The regression model for LMV [Equation (27)] closely emulates the computer model for the 243 cases simulated in this investigation. The correlation coefficient is 0.996 between the LMV predicted by Equation (27) and the computer model simulated LMV.…”

Fouling mechanism and cleanability of ultrafiltration membranes modified with polydopamine-graft-PEG

“…complete anti-fouling performance of the modified membranes, short-term organic adhesion tests may be an initial screen for potential antifouling approaches because most organic adhesion occurs within 2 h (Ridgway et al, 1985). Further, it is quite difficult to translate many laboratory membrane surface modifications to assembled membrane modules that can be used in the long-term bacterial fouling test.…”

Inhibition of Streptococcus mutans Adherence to Hydroxyapatite with Combinations of Alkyl Phosphates and Nonionic Surfactants

“…A noncharged and highly hydrophilic surface, which may result from treatment, e.g., with polyethyl ene glycol, can significantly reduce the adsorption of proteins and cells [Golander et al, 1986;Humphries et al, 1986Humphries et al, , 1987Paul and Jeffrey, 1985;Ridgway et al, 1985]. In a preceding study [Olsson et al, 1990] we investigated the possibility of interfering with strepto coccal adherence to hydroxyapatite (HA) by treating with various polyalkylene oxide derivatives, some of which were found to inhibit Streptococcus mutans ad herence in buffer-treated systems.…”