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BOD test bottles at the laboratory of a wastewater treatment plant. Biochemical oxygen demand (also known as BOD or biological oxygen demand) is an analytical parameter representing the amount of dissolved oxygen (DO) consumed by aerobic bacteria growing on the organic material present in a water sample at a specific temperature over a specific time period.
BOD Bottle BOD test bottles at the laboratory of a wastewater treatment plant. BOD Bottle or an incubation bottle is a main apparatus used for the Biological Oxygen Demand (BOD) test. During the five-day BOD or BOD5 test process, the BOD bottle is used for incubating diluted samples under the 20 °C or 68 °F of temperature.
Both the BOD and COD tests are a measure of the relative oxygen-depletion effect of a waste contaminant. Both have been widely adopted as a measure of pollution effect. The BOD test measures the oxygen demand of biodegradable pollutants whereas the COD test measures the oxygen demand of oxidizable pollutants.
The difference in DO and the dilution factor are used to calculated BOD 5. The resulting number (usually reported in parts per million or milligrams per liter) is useful in determining the relative organic strength of sewage or other polluted waters. The BOD 5 test is an example of analysis that determines classes of materials in a sample.
In environmental chemistry, the chemical oxygen demand (COD) is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution.It is commonly expressed in mass of oxygen consumed over volume of solution, which in SI units is milligrams per liter (mg/L).
One of the easiest control procedures for activated sludge systems is the Constant Mixed Liquor Suspended Solids method. In this method, the operator selects a certain MLSS concentration or range of mix liquor concentrations that produces the best effluent and the highest removal efficiencies.
The acceptance test suite may need to be performed multiple times, as all of the test cases may not be executed within a single test iteration. [9] The acceptance test suite is run using predefined acceptance test procedures to direct the testers on which data to use, the step-by-step processes to follow, and the expected result following ...
The laboratory procedure involves making serial dilutions of the sample (1:10, 1:100, 1:1000, etc.) in sterile water and cultivating these on nutrient agar in a dish that is sealed and incubated. Typical media include plate count agar for a general count or MacConkey agar to count Gram-negative bacteria such as E. coli .