If enteric disease-causing protozoans have been found in the effluent of a water plant, what is the most probable solution?

The most probable solution to effectively address the presence of enteric disease-causing protozoans in the effluent of a water treatment plant is the multi-barrier approach. This strategy incorporates multiple treatment processes that work together to provide comprehensive protection against pathogens, including protozoans.

The multi-barrier approach can include a combination of physical processes such as filtration and sedimentation, as well as chemical treatments. This is particularly important for protozoans, which can be resistant to certain disinfection methods alone. For example, filtration can physically remove many protozoans, while chemical treatments can inactivate those that remain.

Relying solely on a single method, like chemical dosage or filtration alone, may not be sufficient to eliminate all pathogens, especially because protozoans can form cysts that are particularly resilient to disinfection. Sedimentation by itself also does not guarantee the removal of these microorganisms effectively, particularly if the treatment does not include subsequent barriers.

Thus, utilizing a multi-barrier approach ensures that various treatment methods can cover the weaknesses of one another, thereby significantly enhancing the overall safety and quality of the water being treated. This layered protection is essential in maintaining public health and preventing the spread of waterborne diseases.