What are the three types of disinfection methods mentioned in drinking water treatment?

The correct answer identifies the three main categories of disinfection methods used in drinking water treatment: physical, chemical, and biological.

Physical disinfection methods include techniques such as ultraviolet (UV) radiation and filtration, which remove or inactivate pathogens through physical means. This category is crucial because it utilizes the principles of physics—such as the energy from UV light—to achieve disinfection, making it effective against a variety of microorganisms without adding harmful chemicals to the water.

Chemical disinfection encompasses methods that involve the addition of chemical agents to the water to kill or inactivate pathogens. Common chemical disinfectants include chlorine, chloramines, and ozone, which work through various chemical reactions to render harmful microorganisms inactive or destroy them entirely. This method is widely used due to its effectiveness and the residual protection it offers in the distribution system.

Biological disinfection is less commonly referenced in discussions of disinfection methods but generally refers to methods that rely on biological processes or organisms to control pathogens. While not always included in basic lists of disinfection methods, it emphasizes the role of biological filtration systems or biofilms in enhancing water quality and safety.

By understanding these three categories—physical, chemical, and biological—water treatment operators can make informed decisions on the appropriate disinfection methods based