In which of the water treatment processes additional BOD (Biological Oxygen…

The correct answer is Option B (Secondary Treatment Process). In wastewater treatment, secondary treatment specifically targets the removal of dissolved and suspended biological matter using microorganisms. During this stage, aeration tanks provide oxygen to encourage bacterial growth, which consumes organic pollutants (measured as BOD). While the question phrasing about 'providing additional BOD' is technically imprecise, it refers to supplying nutrients and oxygen that support the biological activity needed for organic matter degradation. Primary treatment (Option A) focuses on physical separation of solids through settling, not biological processes. Tertiary treatment (Option C) involves advanced chemical or filtration methods for final polishing, not core biological degradation. Thus, secondary treatment is the essential stage where microorganisms break down organic material to reduce pollution levels.