| 1 |
ADD (1) ml.
Manganous Sulfate to each 300 ml. BOD bottle to
be tested with magnetic stirring bar in bottle. |
|
| 2 |
Add (1) ml. Alkaline Iodide
Azide to each 300 ml. BOD bottle to be tested. |
|
| 3 |
Cap and shake each bottle. Let
settle to half of bottle. Shake once again and
let settle to half of bottle. |
|
| 4 |
Add (1) ml. of Sulfuric Acid
to each BOD bottle. Gloves and safety glasses are
required. |
|
| 5 |
Cap and shake each bottle. |
|
| 6 |
Pour off 100 ml. from each
bottle using a graduated cylinder and save. |
|
| 7 |
Add 0.025N Sodium Thiosulfate
to buret. Put BOD bottle tested on stirring plate
and swirl with magnetic stirrer bar iin bottle. |
|
| 8 |
Record starting point on buret
before titerating. |
|
| 9 |
Titrate while stirring to a
pale straw color. |
 |
| 10 |
Add 2 droppers of Starch
Indicator solution. |
 |
| 11 |
Continue dropwise to the
disappearance of the blue color. This is the end
point. |
 |
| 12 |
Subtract difference readings
from buret. |
|
| 13 |
Proceed to the other bottles
to be tested |
|
| |
Note: If blue color should
return after reaching end point, disregard. If
end point is overshot, see blue lab manual. |
|