What is the significance of achieving 99.9% inactivation during water treatment?

Achieving 99.9% inactivation during water treatment is significant because it indicates that the water treatment process is highly effective in removing harmful pathogens. This level of inactivation suggests that nearly all disease-causing microorganisms, such as bacteria, viruses, and parasites, are eliminated from the water, significantly reducing the risk of waterborne diseases. Safe drinking water must be free of harmful pathogens to protect public health, and achieving this high percentage of inactivation is a critical goal for water treatment facilities.

In contrast, while clarity of water is important for aesthetics and could imply some level of treatment, it does not necessarily indicate pathogen removal. Similarly, the presence of engineered chemicals is not directly related to the inactivation of pathogens, and pressure loss pertains to hydraulics in the system rather than the effectiveness of pathogen removal. Thus, option B most accurately represents the importance of achieving 99.9% inactivation in the context of water safety and public health.