Environmental Engineering MCQ with Answers

Environmental Engineering MCQ with Answers

116) The ratio of 5 day BOD to ultimate BOD is about

Answer is:

2/3

117) In a BOD test, 1.0 ml of raw sewage was diluted to 100 ml and the dissolved oxygen concentration of diluted sample at the beginning was 6 ppm and it was 4 ppm at the end of 5 day incubation at 20°C.The BOD of raw sewage will be

Answer is:

200 ppm

118) The minimum dissolved oxygen which should always be present in water in order to save the aquatic life is

Answer is:

4 ppm

119) The relative stability of a sewage sample, whose dissolved oxygen is same as the total oxygen required to satisfy BOD, is

Answer is:

100

120) Dissolved oxygen in streams is

Answer is:

maximum at noon

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