How do you calculate biochemical oxygen demand?
How do you calculate biochemical oxygen demand?
Measuring biochemical oxygen demand requires taking two measurements. One is measured immediately for dissolved oxygen (initial), and the second is incubated in the lab for 5 days and then tested for the amount of dissolved oxygen remaining (final).
What is the mathematical expression for BOD?
Change Equation
| BOD | = | biochemical oxygen demand |
|---|---|---|
| L | = | ultimate biological demand |
| k | = | deoxygenation rate constant |
| t | = | time |
| D1 | = | initial diluted seeded wastewater dissolved oxygen |
What is BOD and How Is It Measured?
Biochemical oxygen demand, or BOD, measures the amount of oxygen consumed by microorganisms in decomposing organic matter in stream water. BOD also measures the chemical oxidation of inorganic matter (i.e., the extraction of oxygen from water via chemical reaction).
Why is 5 day BOD determined?
The standard oxidation (or incubation) test period for BOD is 5 days at 20 degrees Celsius (°C) (BOD5). The BOD5 value has been used and reported for many applications, most commonly to indicate the effects of sewage and other organic wastes on dissolved oxygen in surface waters (see TECHNICAL NOTE).
How do you make a BOD standard solution?
Add 150 mg glucose and 150 mg glutamic acid to distilled water and dilute to 1 L. Prepare fresh immediately before use unless solution is maintained in a sterile condition. Store all glucose-glutamic acid mixtures at 4°C or lower. Commercial preparations may be used but concentrations may vary.
Why BOD is calculated for 5 days?
Incubation in the dark ensures that no additional oxygen is produced in the samples from photosynthesis. After 5 days, the dissolved oxygen is measured again. The difference between the initial and final oxygen concentrations corrected for BOD of the seed and dilution factor is the BOD.
What does the 5 day BOD test measure?
The test for biochemical oxygen demand (BOD) is a bioassay procedure that measures the oxygen consumed by bacteria from the decomposition of organic matter (Sawyer and McCarty, 1978). The change in DO concentration is measured over a given period of time in water samples at a specified temperature.
Is code for BOD test?
Sampling and sample preservation shall be done as prescribed in IS 3025 ( Part 1 ) : 1986. 300 ml capacity narrow neck special BOD bottles with planed mouth with ground glass stoppers.
How do you calculate BOD in wastewater?
For example: 1.0 mL of a full strength wastewater sample added to 9.0 mL of DI water results in a 0.1 dilution of the wastewater. The DO concentration (mg/L) reduction must then be multiplied by 10 to determine the final BOD concentration.
Why is BOD typically calculated over 5 days?
What is biochemical oxygen demand (BOD)?
Biochemical Oxygen Demand (BOD) is the amount of oxygen, expressed in mg/L or parts per million (ppm), that bacteria take from water when they oxidize organic matter.
How do you calculate BOD for bacteria?
To determine BOD, the amount of oxygen the bacteria use is calculated by comparing the amount left at the end of five days with the amount known to be present at the beginning. At room temperature, the amount of oxygen dissolved in water is 8 mg/L.
What is a common method in measuring BOD?
A common method in measuring BOD analyzes the difference in dissolved oxygen from a sample for five days. A known volume of sample has its initial DO content recorded and after a five day incubation period at 20°C, the sample is removed from the incubator and the final DO content is taken.
How much oxygen is oxidized by the bacteria?
The other two-thirds is oxidized to carbon dioxide and water by the biochemical action of the bacteria on the oxygen dissolved in the water. To determine BOD, the amount of oxygen the bacteria use is calculated by comparing the amount left at the end of five days with the amount known to be present at the beginning.
