Table of Contents
- 1 How much BOD will still be present in the water sample after 10 days of oxidation?
- 2 What is the BOD of sewage to be released into the sea in ppm?
- 3 Why is BOD test done for 5 days?
- 4 Why is BOD done for 5 days?
- 5 How is BOD removed from wastewater?
- 6 How many days are required for BOD measurement and why?
- 7 What is the incubation time for 2\% solution of sewage?
- 8 How do you test for dissolved oxygen in the environment?
How much BOD will still be present in the water sample after 10 days of oxidation?
Keeping dissolved oxygen available at their chosen temperature, investigators found up to 99 percent of total BOD was exerted within 20 days, 90 percent within 10 days, and approximately 68 percent within 5 days.
How do you calculate the BOD of a water sample?
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.
What is the BOD of sewage to be released into the sea in ppm?
wastewater sewage must has BOD around 80 ppm and COD 200 ppm for discharge in see.
How is BOD calculated?
6.1 Take four 300 ml BOD bottles and add 10 ml of samples to two bottles and fill the remaining volume with dilution water….Biological Oxygen Demand (BOD):
| Recommended sample volume for BOD determination | ||
|---|---|---|
| BOD range (mg/liter) | Sample volume (ml) | Dilution water (ml) |
| 0-10 | 300 | 0 |
| 11-30 | 100 | 200 |
| 31-70 | 50 | 250 |
Why is BOD test done for 5 days?
The BOD is an empirical test to determine the molecular oxygen used during a specified incubation period (usually five days), for the biochemical degradation of organic matter (carbonaceous demand) and the oxygen used to oxidise inorganic matter (e.g., sulphides and ferrous iron).
At what temperature the bottles for the BOD test are incubated?
20 °C
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.
Why is BOD done for 5 days?
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).
Why do the COD analysis and BOD analysis give different results for the same waste?
COD is normally higher than BOD because more organic compounds can be chemically oxidised than biologically oxidised. This includes chemicals toxic to biological life, which can make COD tests very useful when testing industrial sewage as they will not be captured by BOD testing.
How is BOD removed from wastewater?
BOD is fairly easy to remove from sewage by providing a supply of oxygen during the treatment process; the oxygen supports bacterial growth which breaks down the organic BOD. Most enhanced treatment units described incorporate some type of unit which actively oxygenates the sewage to reduce BOD.
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.
How many days are required for BOD measurement and why?
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).
Why 5 day 20 degree Celsius or 3 Day 27 degree Celsius BOD is determined?
The DO content of the liquid is determined before and after incubation for five days at 20? or three days at 27?. The difference gives the BOD of the sample after giving allowance for dilution used. Depending upon type of wastewater and COD, suitable dilution factor can be decided with experince.
What is the incubation time for 2\% solution of sewage?
If a 2\% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletio… Home >> Category >> Civil Engineering Mcqs >> Waste Water Engineering Mcqs >> If a 2\% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletio… Q.
What is the BOD of the sewage sample?
Originally Answered: If 2\% solution of sewage sample is incubated for 5 days at 20 deg celsius & depletion of oxygen was found to be 5 ppm, BOD of the sewage is? is the dissolved oxygen (DO) of the diluted solution after preparation (mg/l)
How do you test for dissolved oxygen in the environment?
If you use a meter and probe, you must do the testing in the field; dissolved oxygen levels in a sample bottle change quickly due to the decomposition of organic material by microorganisms or the production of oxygen by algae and other plants in the sample.
Which coagulant is generally not used for treating sewage?
The coagulant which is generally not used for treating the sewage, is 14. The layers of vegetable wastes and night soil alternatively piled above the ground to form a mound, is called A. A heap D. None of these 15. If the flame of a miner’s safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains 16.