Laboratory Certification
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Oxygen measurement techniques
DO Probe Electrochemical method: Composed of two metal electrodes in contact with supporting electrolyte and separated from the test solution by a gas permeable membrane. A constant voltage is placed across the cathode and anode. Oxygen diffuses…
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BOD dilution water
BOD dilution water nutrient solutions can be a source of contamination. If you prepare your own solution, make sure you store the phosphate buffer in a refrigerator. Discard any solution if it becomes cloudy or you observe any "chunks" floating in…
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Calibration & barometric pressure
Pressure adjustments Typically, any barometric pressure measurement that you hear (radio, TV) represents a value that has been corrected to a value relative to sea level. Why is this? For one thing, it's a means of standardizing data. Barometric…
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DO meter calibration
Calibration of the DO meter is arguably the most critical aspect of BOD testing, since we measure the consumption of dissolved oxygen (DO). While calibration may be the center of the DO measurement universe, calibration is in turn impacted by both…
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BOD Basics
Five-day test The BOD test originated in the United Kingdom due to pollution in the London area along the Thames River. They found that sewage dumped in the Thames River took five days to reach the ocean, hence the five-day incubation period. The…