Describe one method of disinfecting drinking water in distribution systems.

Chlorination is a widely used and effective method of disinfecting drinking water in distribution systems. This process involves adding chlorine or chlorine compounds to water, which serves several critical functions in maintaining water quality. Chlorine is a strong oxidant and is capable of killing a variety of pathogens, including bacteria, viruses, and some parasites, thus significantly reducing the risk of waterborne diseases.

The use of chlorine also provides a residual effect; it remains in the water as it travels through the distribution system. This residual chlorine helps to prevent the regrowth of microorganisms and ensures that water remains safe as it reaches taps and outlets. Additionally, chlorination is cost-effective and can be easily integrated into existing water treatment processes.

While boiling water is an effective means of disinfection and ultraviolet light can also effectively inactivate pathogens without adding chemicals, chlorination's ability to both disinfect and maintain a protective residual in the distribution system makes it a cornerstone practice in water treatment. Filtering through sand might remove particulate matter but does not effectively kill pathogens, which is why it is not considered a primary disinfection method.