Which wastewater treatment process removes suspended solids and nutrients to achieve a level of treatment greater than secondary?

• A. Primary treatment
• B. Tertiary treatment
• C. Disinfection
• D. Sour treatment

Answer: (B)

Advanced polishing of wastewater beyond secondary treatment focuses on removing remaining solids and nutrients to achieve higher effluent quality. This is tertiary treatment, where processes like filtration, chemical precipitation, nutrient removal, and sometimes enhanced processes target nitrogen, phosphorus, and any residual solids, often followed by disinfection. Primary treatment mainly removes settleable solids through physical settling, without addressing nutrients. Disinfection targets pathogens rather than nutrients, and the term “sour treatment” isn’t a standard wastewater process.