Image above: (Left) Biofilms in drinking water pipeline. (Right) Tensile test on a biofilm sample in the laboratory..
Photo Credit: Srijan Aggarwal.
Biofilms are communities of microorganisms attached to a solid surface and enmeshed in a self-secreted slime comprising extracellular polymeric substances (EPS). Biofilms occur on nearly all wetted surfaces of the world including pipe walls throughout the water distribution system (WDS) accounting for the bulk (>95%) of bacteria in these systems. The presence of microbial biofilms in the WDS is a potential source of problems such as microbially-influenced-corrosion, taste and odor issues, and increased frictional resistance. Furthermore, these biofilms also provide a hideout in the distribution systems for pathogenic micro-organisms such as bacteria, enteric viruses and protozoan parasites. Not only do the biofilms provide protection to the microorganisms from residual disinfection, but also provide them niches for multiplication and opportunities for subsequent release into the water supply via detachment and sloughing. I will talk about experimental approaches towards removal of already formed biofilms and those for prevention of biofilm formation in the distribution system.