20°C - 1day

25°C- 3day

20°C - 5day

30°C- 5day

5 day BOD is the ultimate BOD.

5 day BOD is greater than 4 day BOD keeping other conditions same.

5 day BOD is less than 4 day BOD keeping other conditions same.

BOD does nof depend on time.

100000

1000

4000

400000

directly proportional to BOD satisfied

directly proportional to BOD remain-ing ,

inversely proportional to BOD satisfied

inversely proportional to BOD re-maining

1/3

2/3

3/4

1