Application of fluid dynamic gauging in the characterization and removal of biofouling deposits

Green cleaning is generally defined as cleaning of a surface by consuming minimal resources in order to lessen the impact on human health and environmental quality. The main aim of this study is to perform cleaning studies of Escherichia coli biofilms grown on (i) polyethylene, (ii) stainless steel, and (iii) glass, to observe their removal behavior under controlled hydrodynamic conditions. The biofilms grown on the three different substrates were tested using the technique of fluid dynamic gauging, which allows for the estimation of the cohesive (within the biofilm structure) and adhesive (between biofilm and substrate) strength of the deposits. The results show that the thickness of biofilm on all substrates increases with time and plateaued at 14 days. Mature biofilms grown on glass have a stronger surface attachment than those on stainless steel and polyethylene. The results also suggest structural weakening after 21 days, implying either the death of cells or the weakening of the extracellular polymer matrix structure.