Question : Three water samples, namely , riverwater , untreated sewage water and secondary effluent discharged from sewage treatment plant were subjected to BOD test, and The obtained values are 60(mg)/L, 307(mg)/L and 200(mg)/L respectively.

Question : Three water samples, namely , riverwater , untreated sewage

1.	Question : Three water samples, namely , riverwater , untreated sewage water and secondary effluent discharged from sewage treatment plant were subjected to BOD test, and The obtained values are 60(mg)/L, 307(mg)/L and 200(mg)/L respectively.
Answer» SOLUTION :307 `(ml)/L` (untrated sewage water). High BOD represents a LARGE number of microbes and high level of pollution. BOD refers to the amount of `O_2` that would be consumed if all the organic matter in 1 litre of water were oxidised by BACTERIA.