Question

Biochemical oxygen demand in a river water

• A. has no relationship with concentration of oxygen in the water
• B. gives a measure of the Salmonella in the water
• C. increases when sewage gets mixed in the water
• D. remains unchanged in the presence of algal bloom

Answer 1

The correct option is C increases when sewage gets mixed in the water

Biochemical oxygen demand (BOD) is a measure of the amount of oxygen required/consumed to remove waste organic matter from one liter of water by aerobic bacteria using the process of decomposition.

Hence, the biochemical oxygen demand in a river water increases when sewage gets mixed in the water.