Active-Bromide and Surfactant Synergy for Enhanced Microfouling Control

Abstract Biofilms are structured microbial communities encased in a matrix of self-produced extracellular polymeric substance (EPS) and pose significant challenges in various industrial cooling systems. A nuclear power plant uses a biocide active-bromide for control of biological growth in its condenser cooling system. This study is aimed to evaluate the anti-bacterial and anti-biofilm efficacy of active-bromide against planktonic and biofilm-forming bacteria that are commonly encountered in seawater cooling systems. The results demonstrated that active-bromide at the concentration used at the power plant (1 ppm) exhibited minimal killing activity against Pseudomonas aeruginosa planktonic cells. Biofilm inhibition assays using Staphylococcus aureus and P. aeruginosa also revealed limited efficacy at 1 ppm concentration. However, the addition of a surfactant, Triton-X 100, in combination with active-bromide displayed a synergistic effect, leading to significant biofilm dispersal of pre-formed P. aeruginosa biofilms. These findings suggest that active bromide alone may be insufficient for microfouling control in the seawater-based condenser cooling system of the power plant. The inclusion of a compatible surfactant that dislodged established biofilms (microfouling) has enhanced the effectiveness of active bromide action.