Biofouling is a major operational problem in reverse osmosis (RO) processes. Recently, direct dosing of non-oxidizing biocides into RO vessels has been attempted to effectively alleviate biofouling. Tributyl tetradecyl phosphonium chloride (TTPC) is an efficient non-oxidizing biocide, but its application to RO processes has been rarely studied. This study aimed to evaluate the applicability of TTPC to RO processes. Scanning electron microscopy and Fourier transform infrared spectroscopy analyses confirmed that the RO membrane was resistant to morphological and chemical damage up to 100,000 mg/L TTPC. Rejection of TTPC determined by a dead-end filtration unit was greater than 99.58%. Furthermore, low concentrations of TTPC (20-40 mg/L) had antimicrobial and antibiofilm properties, as determined by minimum inhibitory concentration, minimum bactericidal concentration, and evaluation of static biofilm formation. TUC also effectively removed biofilms that had already formed on RO membranes. Given these properties of TTPC, this study demonstrates the potential for TTPC as a biocide controlling biofouling in RO processes. (C) 2015 Elsevier B.V. All rights reserved.