Three water samples namely river water, untreated sewage water, and se

1.	Three water samples namely river water, untreated sewage water, and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B, and C, but the Laboratory attendant did not note which was which. The BOD values of the three samples A, B, and C were recorded as 20 mg/L, 8 mg/L, and 400 mg/L, respectively. Which sample of the water is most polluted? Why?
Answer» The sample C is more polluted. So the bottle labelled C was untreated sewage water, because it has the highest BOD 400 mg/L. BOD is a measure of organic matter present in water. The greater the BOD of waste water, more is its polluting potential.

Three water samples namely river water, untreated sewage water, and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B, and C, but the Laboratory attendant did not note which was which. The BOD values of the three samples A, B, and C were recorded as 20 mg/L, 8 mg/L, and 400 mg/L, respectively. Which sample of the water is most polluted? Why?

Answer»

The sample C is more polluted. So the bottle labelled C was untreated sewage water, because it has the highest BOD 400 mg/L.

BOD is a measure of organic matter present in water. The greater the BOD of waste water, more is its polluting potential.