Notifications
Clear all
0
17/12/2021 5:56 pm
Topic starter
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 20mg/L, 8mg/L and 400mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?
1 Answer
0
17/12/2021 5:57 pm
If the BOD level of A, B and C are 20 mg/L, 8 mg/L and 400 mg/L, the most polluted one is sample ‘C’ i.e., untreated sewage water. Sample B is the least polluted and it is river water. Sample A is secondary effluent discharged from a treatment plant.