Biofilm is any group of microorganisms that stick to each other and then oftentimes adhere to a surface. They are characterized by generic diversity and complex structural characters of content and complex community interactions. Their extracellular matrix, which is a collection of extracellular molecules secreted by cells, provides structural and biochemical support to the surrounding cells.

The formation of a biofilm begins with the attachment of free-floating microorganisms to a surface. This is something the Outback Water filtration system is adept at preventing. If the first colonists adhere to a surface, they can anchor themselves more permanently using cell adhesion molecules such as pili(2). The first colonists facilitate the arrival of the other cells by providing more diverse adhesion sites as they begin to build the matrix that holds the biofilm together. Some species are able to attach to a surface on their own while others anchor themselves to the matrix or directly to the earlier colonists. Once colonization has begun, the biofilm will grow through a combination of cell division and recruitment. In cases like this, a gravity-fed emergency water purifier can be the difference between having, or not having, access to safe drinking water.

Biofilm is usually found on solid surfaces, submerged in or exposed to some aqueous solution. (That slimy feeling on our teeth when we wake in the morning is an example.) Biofilms may consist of many species of bacteria and archaea(3) living within the matrix of excreted polymeric compounds. This matrix protects the cells within it and facilitates communication among them through chemical and physical signals. Some biofilms have been found to contain water channels that help distribute nutrients and signaling molecules. In cases like these, the matrix is so strong that the biofilm can actually become fossilized.

Unpleasant tastes and odors in a water supply can be the result of biofilm. But the real question is, can biofilm bacteria cause disease in humans? The answer to this question has been debated for many years when evaluating health risks related to drinking water contamination and bacterial contamination in general. It is commonly believed that in the absence of fecal contamination water is “safe” to drink. However, although most biofilm bacteria are considered harmless to a healthy population there are exceptions. Information available from the CDC (Center for Disease Control) details increasing evidence of potentially harmful bacteria associated with biofilm growth in water distribution systems. Examples of this include the occurrences of Legionella outbreaks that have been linked to drinking water. Other examples are in reported cases of Pseudomonas aeruginosa (a well-known biofilm organism) causing infections in people with compromised immune systems. It has also been discovered that both human viruses and pathogenic cryptosporidium can be trapped within biofilm after contamination events, making this type of contamination potentially hazardous. Which makes water filtration systems such as the Outback Ready System key in survival situations.

The methods generally used to remove biofilm in water treatment and distribution systems may involve high pressure forces, heat shock(4), or the use of chemical disinfectants such as chlorine dioxide. Unfortunately some of these methods are temporary fixes and can result in a major sloughing off of the biofilm which potentially can create a greater adverse effect. In the end, the biofilm will most likely recur. A better approach is a preventative one – treating susceptible areas with gravity fed water filtration or consistent doses of UV light, ozone or a low dose of chemical or chlorine dioxide.

In physical chemistry, the van der Waals forces or van der Waals interaction (named after Dutch scientist Johannes Diderik van der Waals) are the residual attractive or repulsive forces between molecules or atomic groups that do not arise from covalent bonds, or ionic bonds.