Journal of Membrane Science 342 (2009) 145–152 Contents lists available at ScienceDirect Journal of Membrane Science journal homepage: www.elsevier.com/locate/memsci Inhibition of biofilm formation on UF membrane by use of specific bacteriophages Guy Goldman, Jeanna Starosvetsky, Robert Armon ∗,1 Faculty of Civil & Environmental Engineering, Division of Environmental, Water & Agricultural Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel article info Article history: Received 4 March 2009 Received in revised form 8 May 2009 Accepted 21 June 2009 Available online 27 June 2009 Keywords: UF membrane Biofilm Bacteriophages Permeability Prevention Biofouling abstract A model ultrafiltration (UF) continuous recycled system fed with previously sterilized effluents (two sources) was experimentally inoculated with three bacterial species: Pseudomonas aeruginosa, Acineto- bacter johnsonii and Bacillus subtilis (separately and combined). Subsequently, the corresponding specific lytic bacteriophages were supplemented versus control (bacteria without phages) and the experimental set-up was operated for >80 h. The seeded phages lytic activity reduced membrane biofouling by an aver- age of 40% to >60% compared to control. Concentrate phage numbers increased accordingly and some were found in the permeate, however inoculated bacteria were not found in the permeate. Combinations of one, two and three bacterial species in parallel with their specific phages, revealed significant and efficient inactivation rates as well reduced biofouling as detected with high resolution electron scaning microscope (HSEM) and permeability test. The results suggest on potential use of specific lytic phages to prevent UF membrane biofouling. Additionally, future application of specific bacteriophages concept in other membrane processes such as: nanofiltration and reverse osmosis, that encounter less bacterial species diversity, can be successful. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Membranal systems for water treatment such as microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) are constantly exposed to biological clogging due to perpetual biofilm formation throughout the process [1–4]. Raw water as well sewage effluents, as the final product of sewage treatment, still har- bour large numbers of various bacterial species ranging from 10 2 to 10 4 mL -1 respectively [5–7]. The continous flow process applied on these membranes results in biotic (live and dead microorganisms and extracellular polymeric substances—EPS) and abiotic (inor- ganic compounds) scaling. This subject was covered by several excellent reviews revealing the problematic of membranes surface biofouling [1,4]. Biofouling definition derives from the term foul- ing of surfaces (contamination of surfaces with mineral deposits in general) but in this case with emphasize on microorganisms and their extracellular polymeric substances [4]. Practical operative solutions were used and some recently suggested but all with lim- ited success and frequent biofouling reoccurence [8,9]. As already described, the first step of biofouling is formation of conditioning film followed by bacterial adsorption and growth [4]. In a concur- rent process, these steps are simulatenous and at a certain time interval the clogging is inevitable, requiring clean-up by backwash ∗ Corresponding author. Tel.: +972 4 8292377; fax: +972 4 8292377. E-mail address: cvrrobi@tx.technion.ac.il (R. Armon). 1 Member of Grand Water Research Institute. with different chemicals. The backwash cleaning process has two major disadvantages: (1) requires large volumes of water (in scarce water countries this is a serious drawback) and (2) “remaining par- ticulate fouling” that comprises bacteria and other microorganisms [9]. Membrane biofouling is mainly a product of bacterial cells and extracellular polysaccharide substances (EPS) that form a physical barrier, resulting in membrane permeability reduction [2,4]. The EPS has been found to contain beside polysaccharides also proteins, lipids, nucleic acids and a variety of humic substances [10]. An overview of the recent scientific literature on “bacterio- phages therapy” reveals several decades of “renaissance” on phages application in combating a large variety of bacteria in differ- ent experimental areas such as: foam formation reduction [11], slime and biofilm control [12], plant diseases [13], medicine [14], foodborne pathogen control and detection [15–18]. Since the dis- covery of bacteriophages by D’Herrelle and Twort, these acellular microorganisms turned out to be a promising antibacterial prac- tice intended to combat infections, due to their specificity, rapid multiplication properties and limited infectivity to prokaryotic organisms [19,20]. Phages usefulness has been abandoned due to the discovery of antibiotics and our modest knowledge on their molecular biology and physiology at the time [14]. However, in recent times bacteriophages seem to have a large variety of uses in different areas: diabetic wound infections (foot ulcers), topi- cal cleaning and disinfection [21], food industry (meet and poultry spraying against Salmonella sp.) [22], well clogging prevention [23] and many others. Historically, Doolittle et al. [24] were perhaps the first to show the potential use of T4 bacteriophage to act lyt- 0376-7388/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.memsci.2009.06.036