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Biochemical Oxygen Demand. BOD is defined as the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down the organic material present in a water sample, at a specific temperature and specified period.
What is BOD in life science?
Biochemical oxygen demand (BOD) represents the amount of oxygen consumed by bacteria and other microorganisms while they decompose organic matter under aerobic (oxygen is present) conditions at a specified temperature. The decay of organic matter in water is measured as biochemical or chemical oxygen demand.
What is BOD short answer?
Biochemical oxygen demand (BOD) is the amount of dissolved oxygen (DO) needed (i.e. demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period.
What is BOD class12?
A) The amount of O2. Biochemical oxygen demand (BOD) is defined as the amount of oxygen used by bacteria and other microorganisms during the process of decomposition of organic matter under aerobic (oxygen is present) conditions at a particular temperature and in specific time periods.
Why is COD higher than BOD?
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.
What is BOD Class 9?
BOD measures the amount of oxygen utilized by microorganisms for the process of decomposition of the organic matters in the water bodies. It symbolizes the amount of organic pollution present in an aquatic ecosystem. Biological oxygen demand can be used as an indicator of the level of environmental pollution.
What is BOD formula?
BOD = biochemical oxygen demand, mg/L. When seed is added, seed control tests must be done to determine the amount of oxygen depleted by the seed. Calculation of BOD includes a correction factor for seed as expressed by Equation 2. where: IDO = initial D.O. of diluted sample, mg/L.
What is BOD and do in water?
The DO (dissolved oxygen) has a direct relationship with the BOD (biochemical oxygen demand) in that it is determined to test the level of the BOD in water, especially in wastewater when microorganisms and an available food supply are present in water body.
What is meant by COD?
abbreviation for cash on delivery or collect on delivery: used to mean that payment will be made when goods are delivered: The goods will be shipped to you COD.4 days ago
What is BOD and its importance?
The biological oxygen demand (BOD) is also called biochemical oxygen demand. The BOD refers to the amount of oxygen required for the biotic degradation of organic matter in bodies of water. The BOD is a pollution parameter mainly to asses the quality of effluent or wastewater. The significance of BOD is very clear.
How do you reduce BOD value?
These are the best practices for reducing BOD and TSS that facility managers should know: Focus on removing TSS from wastewater first. Get a properly sized EQ tank. Control the pH of the waste stream. Install a modern plate pack DAF made of stainless steel or plastic. Use a regenerative turbine air dissolution pump.
What is BOD of river water?
‘Biochemical oxygen demand’ is a measure of how much dissolved oxygen is being consumed as microbes break down organic matter. A high demand, therefore, can indicate that levels of dissolved oxygen are falling, with potentially dangerous implications for the river’s biodiversity.
Why is BOD test 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).
Which value of BOD is correct for average sewage?
BOD values are usually reported in either ppm values or in mg/L values. Unpolluted rivers typically have a BOD below 1 mg/L. Moderately polluted rivers vary between 2 to 8 mg/L. Untreated sewage averages between 200 and 600 mg/L while efficiently treated municipal sewage would be 20 mg/L or less.
What is BOD Toppr?
Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period.
What causes high COD in wastewater?
COD increases as the concentration of organic material increases. It also increases if inorganic compounds susceptible to oxidation by the oxidant (typically dichromate) are present. Water with high COD typically contains high levels of decaying plant matter, human waste, or industrial effluent.
In which water BOD is maximum?
Notes: BOD is amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period, for running rivers, it would be minimum and for Untreated Municipal waste water it would be maximum.
Is high BOD in water good?
Higher BOD indicates more oxygen is required, which is less for oxygen-demanding species to feed on, and signifies lower water quality. Inversely, low BOD means less oxygen is being removed from water, so water is generally purer.
What is removed during secondary wastewater treatment?
Secondary Treatment The secondary stage of treatment removes about 85 percent of the organic matter in sewage by making use of the bacteria in it. The principal secondary treatment techniques used in secondary treatment are the trickling filter and the activated sludge process.
How do you measure BOD in water?
BOD measurement requires taking two samples at each site. One is tested immediately for dissolved oxygen, and the second is incubated in the dark at 20 C for 5 days and then tested for the amount of dissolved oxygen remaining.
What is a good BOD level?
A BOD level of 1-2 ppm is considered very good. There will not be much organic waste present in the water supply. A water supply with a BOD level of 3-5 ppm is considered moderately clean.
