Microbial safety in water treatment: Which process step is specifically intended to kill infective bacteria present in water supplied for public use?

Introduction / Context:
Drinking water treatment trains are designed to remove particles, reduce organics, and ensure microbiological safety. It is essential to distinguish between steps that condition water and the step that specifically inactivates pathogens before distribution.

Given Data / Assumptions:

• Typical plant includes coagulation/flocculation, sedimentation, filtration, and a final chemical or physical disinfectant step.
• Goal is to achieve regulatory microbial standards.

Concept / Approach:
Disinfection refers to the targeted inactivation of pathogens to safe levels, commonly using chlorine/chloramines, ozone, or ultraviolet irradiation. Sterilisation implies complete destruction of all forms of microbial life (including spores), which is not required or practical for municipal water. Aeration mainly strips gases and oxidises some species; it is not a reliable pathogen inactivation step.

Step-by-Step Solution:

Verification / Alternative check:
Regulatory frameworks require measurable disinfectant residuals and log reductions of specified microbes, confirming disinfection as the correct step.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming filtration alone guarantees pathogen safety; filtration and disinfection act in series for robust protection.

Final Answer:
disinfection