Microbial Control Overview and Water System Challenges

Microbial control is essential to ensure the health and aesthetic qualities of a great variety of processes, systems and materials. Although established microbial control methods usually are effective, scenarios involving microbial species able to evade control measures and create problems are possible. As an ecosystem matrix, biofilms can provide microorganisms the means to colonize austere, inhospitable environments subjected to microbial control. If able to reproduce and shed, biofilm-associated microbes could reach elevated levels leading to contamination and harmful consequences. This overview highlights waterborne microbes of health concern that are able to exist in biofilms of water systems and overcome typical disinfectant treatments. As examples, the presentation includes (a) selection of multiply antibiotic-resistant opportunistic pathogens in pipe biofilm of the distribution system of a municipal chlorinated drinking water system, (2) Legionella pneumophila colonization of pipe biofilm and hot water tank sediment of a hot water system receiving municipal chlorinated drinking water and (3) Pseudomonas aeruginosa persistence in whirlpool spa biofilm and reoccurrence following shock treatment with bromine.