Advantages And Disadvantages Of Biofilms

Biofilms are defined as complex aggregates of microorganisms which are interlinked and secrete extracellular slime, which forms the matrix for the films. The extracellular slime is chiefly made up of polysaccharides. Biofilms are usually irreversibly attached to a surface, in that once a biofilm is attached to a surface, it is quite difficult to remove. Mineral salt crystals, clay and silt particles etc. are also sometimes present within the biofilm matrix (depending upon the surroundings). The majority of biofilms found in the environment are either phytoplanktonic or bacterial (Donlan, Sept 2002).

Biofilms can form on many surfaces, including natural aquatic systems, human teeth, medical devices like artificial heart valves and catheters,

There are several types of treatment methods present but biological treatment methods have gained much traction in the recent years due to their low operation costs, comparatively benign effects on the environment and their ease of handling and maintenance. Biological wastewater treatment methods can be subcategorized into dispersed growth systems and attached growth systems. Biofilms fall under the latter category (Sehar & Naz, 2016)

In attached growth systems, microbes get attached to a surface to form a biofilm. The formation of the biofilm depends on factors like the type of surface used, presence of polymeric molecules on the surface and cell-cell interactions. Wastewater is passed through the surfaces on which the biofilms are attached. The microorganisms in the biofilm utilize the organic matter present in the wastewater and subsequently, the biofilms grow. There are four predominant reactor types that utilize this technology. Trickling Filters (TFs), Rotating Biological Contactor (RBC) Systems, Constructed Wetlands and Membrane Bioreactors (MBRs) (Sehar & Naz, 2016). Trickling Filters and Membrane Bioreactors are focused on in this