California Wastewater Treatment Operator Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Denitrification in wastewater treatment refers to the biological process where nitrates (NO3-) are converted into nitrogen gas (N2) and subsequently released into the atmosphere. This process is crucial for the nitrogen cycle as it helps to remove excess nitrates from the wastewater, which can contribute to water quality issues such as nutrient pollution and eutrophication in receiving waters.

During denitrification, specific bacteria utilize nitrates as an electron acceptor in the absence of oxygen, leading to their reduction to nitrogen gas. This process typically occurs in anaerobic conditions where the bacteria thrive. The transformation of nitrates to nitrogen gas is important because it effectively reduces nitrogen load in the effluent, promoting better environmental health and compliance with discharge regulations.

Other options present processes that do not pertain to denitrification. The removal of solid waste involves mechanical or physical means to separate waste materials, while the addition of nutrients addresses nutrient deficiencies independent of nitrogen removal. Filtering out pathogens is a separate process often associated with disinfection methods in wastewater treatment, rather than the nitrogen cycle.