Review of Biochemical Oxygen Demand (BOD) by Standard Method 5210B including method steps as well highlight products to make your setup of a BOD batch quick and easy.
Obtaining high-quality dilution water is important when doing a BOD batch, becase it will come into contact with every sample involved in your batch. Deionized water requires the addition of several trace nutrients to ensure a proper environment for the incubation of bacterial populations.
Influents are often toxic and highly variable. Effluents are chlorinated to remove microbial populations. To overcome these problems use a freeze-dried seed such as Polyseed
The glucose-glutamic acid check standard is the primary measure for precision and accuracy of a BOD batch. For ease of use, prepared vials with the appropriate amount of glucose and glutamic acid are recommended.
Choose between traditional glass bottles or plastic bottles. These plastic bottles are specially designed and approved by the EPA for use in the determination of biochemical oxygen demand and dissolved oxygen. The bottles are manufactured with a special coating on the inside to prevent the migration of oxygen through the plastic and also prevents the leaching of oxidizable materials into your samples during incubation. Plastic bottles fit your standard stoppers and overcaps.
If the sample is outside of the acceptable pH range, it needs to be adjusted with dilute solutions, a sulfiric acid, or sodium hydroxide. If chlorine is present, it needs to neutralized with sodium sulfite. Each sample needs to have several dilutions prepared to ensure an appropriate BOD value. Samples of unknown strength or that are highly variable may need more than 3 bottles in order to ensure an appropriate depletion.
In order for a sample to be acceptable, it must have a minimum of 2mg of oxygen per Liter depletion and a residul of least 1 mg of oxygen per Liter remaining. This is known as the 2:1 rule
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