The APHA Standard Methods 24th Edition has recently been released, and MANTECH is happy to provide the following updates that apply for Standard Method 5210B for Biochemical Oxygen Demand:
Dissolved Oxygen Checks
- For Automated Biochemical Oxygen Demand (BOD) testing, dissolved oxygen measurements are to be performed according to Standard Method 4500-O
- Dissolved oxygen (DO) measurements should see a “calibration check” performed where the dissolved oxygen of a saturated DO solution is measured throughout the sample run
- This saturated DO solution is prepared by aerating DI water with clean compressed gas
- Gas should pass through an activated carbon filter to remove oil and contaminants from the air if needed
- MANTECH BOD Pro systems can be set to perform these calibration checks automatically after a user-specified number of bottles, repeating through the entire set of samples
- Other checks such as a zero-DO check can also be included, with the option for multiple types of checks within a single run
Minimum Residual DO and Minimum Depletion
- Standard Methods 23rd Edition allowed exceptions to residual DO and depletion rules when testing undiluted samples and all bottles fail the criteria
- Standard Methods 24th Edition does not allow this same exception. All samples must meet the residual DO and depletion rules
- BOD Pro software conforms to both 23rd and 24th Edition rules for performing Automated BOD, allowing users to easily change and set customized “lab specific” rules when desired
Dilution Water Check (Blanks)
- Standard Methods 23rd Edition states that if the average blank depletion is >0.2 mg/L, record the data and clearly identify such samples in data records
- Standard Methods 24th Edition states that if the average blank depletion is >0.2 mg/L, evaluate the cause and make corrections
- The main difference here is the 24th Edition is quite clear that blank depletions higher than the recommended amount of 0.2 mg/L requires corrective action
- This is because blank depletions higher than this can lead to unexpected effects on sample results, and it is an indication of some aspect of the test creating “false oxygen demand” which will not be consistent across all bottles.
- In addition to flagging bottles that fail the average blank depletion rule, MANTECH systems can use dynamic logic to take certain actions such as re-reading, stopping the run, and providing user-friendly instructions in the case of blank failures.
Rapid and Green BOD Estimation
- MANTECH can provide 10 minute BOD estimation as a low-cost add-on for BOD Pro systems
- Ensure every BOD sample receives a valid reportable result, even for samples with unknown BOD concentrations
- Reduce the number of dilutions required per sample, saving on time and reagents
- Easy and safe method requiring no extra PPE or specific lab training
Through the use of MANTECH’s BOD Pro Analyzers, you can be confident that your laboratory is always conforming to the most recent version of Standard Methods, while providing quality results and freeing up laboratory technicians’ time. Visit our BOD Pro Homepage to learn more!
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