Membrane Biofouling of Seawater Reverse Osmosis Initiated by Sporogenic Bacillus Strain

Abstract

The objective of this study was to assess the biofouling characteristics of the Bacillus biofilm formed on reverse osmosis (RO) membranes. For the study, a sporogenic Bacillus sp. was isolated from the seawater intake to a RO process, with two distinct sets of experiments performed to grow the Bacillus biofilm on the RO membrane using a lab-scale crossflow membrane test unit. Two operational feds were used, 9 L sterile-filtered seawater and 10 9 Bacillus cells, with flow rates of 1 L/min, and a constant 800 psi-pressure and pH 7.6. From the results, the membrane with more fouling, in which the observed permeate flux decreased to 33% of its initial value, showed about 10 and 100 times greater extracellular polymeric substances and spoOA genes expressions, respectively, than the those of the less fouled membrane (flux declined to 20% of its initial value). Interestingly; however, the number of culturable Bacillus sp. in the more fouled membrane was about 10 times less than that of the less fouled membrane. This indicated that while the number of Bacillus had less relevance with respect to the extent of biofouling, the activation of the genes of interest, which is initiative of biofilm development, had a more positive effect on biofouling than the mass of an individual Bacillus bacterium.

Source water quality shaping different fouling scenarios in a full-scale desalination plant at the Red Sea

“…The use of SEM-EDX tools for surface analysis of either fouling layer (Ang and Elimelec, 2009;Lee et al, 2010;Ridgway et al, 1983;Schneider et al, 2005;Subramani and Hoek, 2008) or virgin membrane structure (Ang and Elimelec, 2009;Pacheco et al, 2010;Subramani and Hoek, 2008) is common in ultrastructural studies of RO membranes. However, a fouled membrane study with cross sectional analysis, which could offer information in terms of micro and nano scale details of internal structures of the foulant layer, is rarely found in the literature.…”

Composition and Molecular Identification of Bacterial Community in Seawater Desalination Plants

“…From an application point of view, it is worth mentioning that Sphingomonas and Pseudomonas have been described as containing an open reading frame coding for enzymes that are necessary for the initial stages of biofilm development [13]. Therefore, these molecular identifications open the door to studying the gene expression levels that encode the attachment protein and the biofouling potential of these bacteria.…”

“…Sequences of the forward (F) and reverse (R) primers, for 16s rRNA gene. Sequences were retrieved from[13] [14].…”

Anode direct contact for enhancing power generation and biofouling reduction in ultrafiltration microbial fuel cells

“…The total cell number was counted using confocal laser scanning microscopy (CLSM) after fluorescence staining of bacteria cells using 4'‐6‐diamidino‐2‐phenylindole (DAPI). All counting and staining procedures follow those given in a previous study …”