What size bottles should be used for setting up BOD samples?

When setting up Biochemical Oxygen Demand (BOD) samples, 60 mL BOD bottles or larger are recommended in order to ensure that the sample volume is adequate to measure the oxygen demand accurately. The primary function of these bottles is to allow for sufficient water volume, which helps to dilute the organic matter within the sample and provides enough sample for accurate DO (dissolved oxygen) measurements during the incubation period.

Using a 60 mL bottle or larger accommodates the typical 5-day incubation period required for BOD testing without risking the depletion of oxygen in the sample due to high concentrations of organic material. If smaller bottles were used, there could be insufficient volume for representative sampling, or they might not properly support the microbial activity necessary for accurate BOD readings.

Larger bottles also provide a consistent environment for the microbial processes at play, which is crucial for obtaining reliable and reproducible BOD data.