Which of the following industrial wastewater pollutants can be treated effectively by activated sludge?

Activated sludge is a biological treatment process used primarily for the removal of biodegradable organic matter from wastewater. It is particularly effective at treating pollutants such as Biochemical Oxygen Demand (BOD). The activated sludge process utilizes microorganisms to decompose organic pollutants in the presence of oxygen, thereby reducing both BOD and Chemical Oxygen Demand (COD).

When considering the specific context of the question, the main strength of the activated sludge process lies in its ability to address the organic matter represented by BOD. While COD also measures the total oxygen demand by organic and inorganic substances, it includes both biodegradable and non-biodegradable components; thus, it is less specific to the efficiency of the activated sludge treatment. Consequently, while COD reduction can occur in the activated sludge process due to the biological breakdown of organics, BOD is a clearer indicator of the direct impact and effectiveness of the process in treating organic pollution.

The other pollutants such as Total Suspended Solids (TSS) and nutrients (nitrogen and phosphorus) can also be influenced by the activated sludge process, but they do not exclusively represent the primary function of this treatment method. TSS may settle out in clarifiers as solids, and nutrients can be removed through specific adaptations of the activated sludge process, but they