What role do protozoa play in wastewater treatment?

Protozoa play a significant role in wastewater treatment, particularly in enhancing the removal of pathogenic organisms. They act as micro-predators in the treatment process, consuming bacteria and other smaller microorganisms. This biocontrol helps to maintain a balanced microbial community within the treatment system, which is essential for effective wastewater purification.

By preying on harmful pathogens, protozoa not only reduce the numbers of these organisms but also contribute to overall water quality improvement by assisting in the decomposition of organic matter. This action helps ensure that treated effluent meets regulatory standards for pathogen reduction, making it safer for discharge into the environment or for reuse.

The other roles presented in the choices do not accurately depict the primary function of protozoa in wastewater treatment, emphasizing the importance of their role in pathogen removal as a critical component of biological treatment processes.