Primary wastewater treatment targets the removal of what?

Primary wastewater treatment targets the removal of what?

• A. pathogens
• B. priority pollutants
• C. suspended solids
• D. phosphates

Answer: (C)

Primary treatment is about removing solids by physical means, mainly through screening and settling in a clarifier. The goal is to lift out the suspended solids that will settle to form sludge, leaving a clearer effluent and reducing the solids load for downstream processes. This is why suspended solids are the target: they are the portion of wastewater that can be removed by gravity and physical screening at this early stage. Pathogens are addressed later through disinfection and biological treatment, priority pollutants require more advanced treatment, and phosphates need nutrient removal steps, not the primary settling stage.

Primary treatment is about removing solids by physical means, mainly through screening and settling in a clarifier. The goal is to lift out the suspended solids that will settle to form sludge, leaving a clearer effluent and reducing the solids load for downstream processes. This is why suspended solids are the target: they are the portion of wastewater that can be removed by gravity and physical screening at this early stage. Pathogens are addressed later through disinfection and biological treatment, priority pollutants require more advanced treatment, and phosphates need nutrient removal steps, not the primary settling stage.