New York State Wastewater Practice Exam – Complete Prep Guide 2026

Filtration is primarily a physical separation process that can remove particles from water, including some pathogens, but it does not reliably destroy pathogenic microorganisms. The primary function of filtration is to reduce turbidity and remove suspended solids. While certain filtration methods, such as microfiltration or ultrafiltration, can physically remove bacteria and some viruses, they do not inactivate or kill these microorganisms.

In contrast, chlorination, ultraviolet radiation, and the activated sludge process actively contribute to the destruction of pathogens. Chlorination involves the addition of chlorine to water, which chemically reacts with and inactivates microorganisms. Ultraviolet radiation uses high-intensity light to disrupt the DNA of pathogens, effectively rendering them unable to reproduce. The activated sludge process promotes the growth of microorganisms under aerobic conditions, which can lead to the breakdown of organic matter and the inactivation of pathogens through biological processes.

Thus, filtration is not considered an acceptable treatment process specifically for the destruction of pathogenic microorganisms.