California Wastewater Treatment Operator Practice Exam

Tertiary treatment is the final step in the wastewater treatment process and is specifically designed to improve effluent quality before it is discharged into the environment. One of its key functions is to enhance the removal of pathogens, which are microorganisms that can cause disease.

This process often includes advanced filtration, disinfection, and sometimes biological treatments that target remaining pathogens after the primary and secondary treatments. For example, methods used in tertiary treatment may involve the use of chlorine, ultraviolet light, or ozone to effectively kill or inactivate bacteria, viruses, and protozoa. By utilizing these advanced techniques, tertiary treatment significantly reduces the concentration of pathogens in the treated water, ensuring it meets health and environmental standards for safe discharge or reuse.

In comparison, primary treatment primarily focuses on the physical removal of solids and does not effectively eliminate pathogens, while secondary treatment enhances the biological removal of organic matter and some pathogens but may still leave certain microorganisms present. Preliminary treatment is mainly concerned with the initial screening and removal of large solids and does not address pathogen removal at all. Therefore, tertiary treatment is the most effective at enhancing pathogen removal.