Biofilm parameters influencing biocide efficacy

Area of Science:

• Environmental microbiology
• Water treatment technologies
• Antimicrobial resistance

Background:

• Bacterial biofilms pose significant challenges in various settings, including water systems and healthcare.
• Understanding factors affecting biofilm removal is crucial for effective disinfection strategies.

Purpose of the Study:

• To investigate the impact of biofilm cell density, species composition, and abiotic particles on monochloramine disinfection.
• To determine the rate coefficients for disinfection and detachment processes.

Main Methods:

• Culturing mono- and binary population biofilms of Pseudomonas aeruginosa and Klebsiella pneumoniae.
• Treating biofilms with monochloramine in a continuous flow annular reactor.
• Quantifying cell numbers and colony formation to calculate disinfection and detachment rates.

Main Results:

• Disinfection rates generally exceeded detachment rates, with poor correlation between the two.
• Overall decay rate coefficient showed a parabolic dependence on cell density, peaking near 10(8) cfu/cm(2).
• Species interactions influenced decay rates, with P. aeruginosa decaying slower in K. pneumoniae-dominated biofilms. Kaolin and calcium carbonate particles reduced disinfection efficacy.

Conclusions:

• Biofilm susceptibility to monochloramine is multifactorial, influenced by cell density, species interactions, and abiotic components.
• Optimal cell density exists for monochloramine efficacy, and species composition can modulate susceptibility.
• Abiotic particles hinder effective biofilm disinfection, necessitating consideration in treatment strategies.