Question

How, in the course of water treatment, might some of these pathogens be missed?

Answer 1

Many of the pathogenic bacteria have a property to form endospores. It is a tough and dormant structure produced by some of the pathogenic bacteria e.g.  Clostridium tetani, Bacillus cereus, Clostridium botulinum, Bacillus anthracis and Bacillus thuringiensis. An endospore is covered by the inner membrane, germ cell wall, outer membrane and external coat (figure). This four-layer structure present in the endosomes gives them resistance to survive in the condition of heat and chemicals. Disinfectants used during the water purification to kill the pathogenic bacteria include chlorine, chlorine dioxide and ozone. monochloramine. Endospores can easily survive in the presence of all the chemicals. Boloing at 100 degree celsius is used to kill pathogens bacteria in the water. However, these endospores are also resistant to heat at 100 degrees celsius. Therefore, the formation od endospore by some of the pathogenic bacteria may allow them to escape from the normal disinfection process used to purify water.