Question

Q.19. Which of the following constitutes wastewater?
(a)Harvested rainwater
(c)Water taken up by plants
(b)Water used for laundry
(d)Water present in a bird-bath​

Answer 1

Answer:

Water used for laundry

Answer 2

(b)Water used for laundry is the correct answer.

• Wastewater refers to the water with high levels of Chemical Oxygen Demand abbreviated as COD and Biological Oxygen Demand abbreviated as BOD.
• Water used by laundry contains high amount of soaps and chemicals, which increases chemical toxicity of the water. Thus, increasing its COD or Chemical Oxygen Demand.
• Chemical Oxygen Demand is defined as the total amount of all chemicals in the water that can be oxidized. Biochemical Oxygen Demand is defined as the measure of the amount of food that bacteria can oxidize.