THE EFFECTS OF REPEATED CHLORINATION ON BIOFILM DEVELOPMENT UNDER DIFFERENT NUTRIENT CONCENTRATIONS USING A MICROLFUIDIC DEVICE

Abstract

Bacterial biofilms are known to adapt well in niches with nutrient scarcity and have the ability to recover significantly in the presence of residual chlorine, suggesting that nutrient deprivation and chlorination have been individually ineffective in eradicating biofilms. This study investigated biofilm development under different nutrient conditions coupled with subsequent chlorination. The real-time monitoring of biofilm disinfection and regrowth was successfully observed in a single microfluidic device. Biofilm formation was enhanced with increasing nutrient concentrations, but the established biofilms with varying robustness experienced similar removal rates during the first chlorination. Analysis of biofilm removal efficiencies revealed that introducing a higher chlorine concentration (5mg/L) flowed by subsequent lower dose (2mg/L) was more effective in destabilizing the biofilms. Biofilm regrowth was accelerated after the first chlorination but significantly reduced after the second chlorination, indicating that repeated chlorination was effective in reducing the rate of regrowth.