The role of surface copper content on biofilm formation by drinking water bacteria

. The antimicrobial action of the selected materials seem not to be related to copper leaching or to the formation of reactive oxygen species. However, bacterial-copper contact demonstrated damage to bacterial membranes. The alloy containing 96% copper was the most promising surface in reducing biofilm culturability and viability, and was the only surface able to avoid the regrowth of single species biofilms when in contact with high nutrient concentrations. The alloy with 87% copper was shown to be unsuitable for use in chlorinated systems due to the high copper leaching observed when exposed to free chlorine. The presence of viable but non-culturable bacteria was remarkable, particularly in dual species biofilms. The overall results provide novel data on the role of copper alloys for use under chlorinated and unchlorinated conditions. Copper alloys demonstrated comparable or even higher biofilm control effects than elemental copper surfaces.