Water Nuggets Practice Exam

Which organism can escape coagulation and pass through a granular filter?

1. Cryptosporidium

2. Giardia

3. Naegleria

4. Entamoeba

The correct answer is: Cryptosporidium

Cryptosporidium is the correct choice because it is known for its ability to resist conventional water treatment processes, including coagulation and filtration. The organism has a thick protective cyst that allows it to withstand chlorine disinfection and pass through standard granular filters used in water treatment facilities. This species is microscopic, with a size that enables it to evade filtration systems, which typically remove larger pathogens. In contrast, Giardia, though also a protozoan parasite found in water, is generally larger and can be effectively removed by granular filtration methods. Naegleria, a free-living amoeba, primarily affects water temperatures above 25°C and can also be filtered out by conventional systems. Entamoeba is associated with intestinal infections, but like Giardia, it is less able to evade standard water treatment processes. Hence, Cryptosporidium stands out as the organism capable of escaping coagulation and passing through granular filters.