Toxic organics can be removed or reduced from waste streams by which combination of steps?

• A. Precipitation and Coagulation
• B. Aeration, Carbon Adsorption and Settling
• C. Chlorination
• D. Distillation and Drying

Answer: (B)

Toxic organics in waste streams are best removed by a combination of steps that address both dissolved compounds and any solids carrying contaminants. Aeration introduces oxygen and promotes breakdown or volatilization of some organics, helping to reduce their concentration. Activated carbon adsorption then grabs a wide range of dissolved organic molecules, pulling them out of the water and keeping them from passing through the system. Settling follows to remove suspended solids and any organics bound to those particles, further lowering the overall contaminant load. Used together, these steps tackle both dissolved and particulate-associated organics for a more effective cleanup.

Precipitation and coagulation mainly target suspended solids and some metals, not dissolved organics; chlorination disinfects but doesn’t substantially remove organic contaminants and can form byproducts; distillation and drying separate water but are energy-intensive and not the standard approach for broad organic removal in wastewater.