Plot the curve All info is given Show steps to solve An unse

An unseeded BOD test was conducted on a raw domestic waste water sample. The wastewater portion added to each 300 ml bottle was 8.0 ml. The dissolved oxygen values and incubation peri ods are listed below. Plot a BOD versus time curve and determine the 4 d BOD value. Bottle Initial DO Incubation Final DO number mg/L days mg/L 8.4 8.4 8.4 8.4 6.2 8.4 5.9 8.4 8.4 8.4 5.2 4.4 8.4 8.4 4.6 8.4 0.8 3.5 8.4

Solution

BOD of raw domestic waste water

Bottle no

Initial DO

(mg/L)

Incubation Days

Final Do

(mg/L)

BOD

(mg/L)

1

8.4

0

8.4

0

2

8.4

0

8.4

0

3

8.4

1

6.2

8.234667

4

8.4

1

5.9

8.242667

5

8.4

2

5.2

8.261333

6

8.4

2

5.2

8.261333

7

8.4

3

4.4

8.282667

8

8.4

3

4.6

8.277333

9

8.4

5

0.8

8.378667

10

8.4

5

3.5

8.306667

4th day BOD value 8.31774mg/L

(Sorry, the graph couldnt paste in this window)

Bottle no	Initial DO (mg/L)	Incubation Days	Final Do (mg/L)	BOD (mg/L)
1	8.4	0	8.4	0
2	8.4	0	8.4	0
3	8.4	1	6.2	8.234667
4	8.4	1	5.9	8.242667
5	8.4	2	5.2	8.261333
6	8.4	2	5.2	8.261333
7	8.4	3	4.4	8.282667
8	8.4	3	4.6	8.277333
9	8.4	5	0.8	8.378667
10	8.4	5	3.5	8.306667