Raw water always contains Bacteria and Bacterial endotoxins that exists in a dynamic state. Dynamic state means the bacterial count is always variable, depending on environmental conditions controlling the rate of growth, bacteria will continually proliferate, while other bacteria are dying.
Gram-negative and gram-positive bacteria can be present in a water. Gram-positive bacteria have a single cell wall. Gram-negative bacteria contain an inner membrane and a second outer membrane. The presence of the outer membrane is extremely important.
Due to outer membrane, the gram-negative bacteria have ability to receive nutrients from the environment into the cell. Phospholipid, lipopolysaccharide and protein are the main components of outer membrane of gram-negative bacteria. The lipopolysaccharide is extremely stable.
Lipopolysaccharide is considered an endotoxin because the toxin is synthesized as part of the bacteria cell structure. Endotoxins are released when gram-negative bacteria cell are destroyed.
Endotoxins are always harmful to humans. When we get infected by endotoxins, due to our immunity system, body temperature rises. On the basis of the body’s response to bacterial endotoxins, they are often referred to as pyrogens.
As gram-negative bacteria will be found in raw water supplies, particularly supplies from a surface source or groundwater source influenced by a surface source, and since the raw water supplies will contain a mechanism for destroying bacteria, bacterial endotoxins may be present in raw water supplies. Bacterial endotoxins are associated with biofilm.