Oxygen in a sample is Supersaturated
The only time this is a problem is with effluent samples. The reason for this is that the oxygen saturates at some lower value (for example 4 degrees C), then the sample size is extremely large, sometimes as large as 300 mL in a BOD bottle.
- Warm the sample to about 20 degrees C.
- Shake the container containing the sample for 5-10 minutes after warming.