Tertiary system wastewater treatment, also known as deep treatment or advanced treatment, is a process of further purifying wastewater after primary and secondary treatment. Its main purpose is to remove dissolved organic matter, inorganic matter, pathogens etc.

Deodorants that can remove odors from wastewater: 1. Activated carbon, 2. Oxidants, 3. Biological deodorants, 4. Chemical precipitants, 5. Adsorbents. Scientists and engineers have developed a variety of deodorants for different odor components in wastewater.