ABSTRACT
Microbial biofilms are very broadly defined as a consortium of interacting microorganisms that are associated to an environmental interface, typically a solid-liquid interface, by a self-produced polymeric matrix (Figure 15.1). At almost any aqueous interface, biofilms can be found to have diverse impacts on the surrounding environments. The first recognition of microbial biofilms was made by environmental (sanitary) engineers in the late 1800s.1 Used as “trickling filters” for biological treatment (Figure 15.2), sewage was applied to coke, cinder, crushed stone, gravel, crushed slag, burned clay, and broken brick, and it was noted that “After more than a year’s continuous use, a casual observer on taking the crushed stone in his hand would note no change in it. A microscopic examination, however, would reveal a thin film on the surface of the particles. It is in this film that the bacteria live that cause the purification.”2
