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BOD stands for Biological Oxygen Demand. It is the amount of dissolved oxygen required by aerobic organisms to break down organic material present in the water. It indicates the amount of organic pollution present in an aquatic ecosystem.
What is BOD what is its significance on water quality?
The dissolved oxygen readings are usually in parts per million (ppm). 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 the significance of COD and BOD?
Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) are two of the most important parameters to characterise (measure the degree of pollution) of wastewater. BOD, the biological demand for oxygen a source of water has, is the amount of oxygen used by microorganisms to break down organic substances.
What is BOD COD ratio?
BOD (Biochemical oxygen demand) is the pollution index of any water sample. BOD : COD (Chemical oxygen demand) ratio using the formulated seed comes in the range of 0.7-0.8 whereas that using BODSEED comes in the ratio of 0.5-0.6. The ultimate BOD (UBOD) was also performed by exceeding the 3-day dilution BOD test.
What affects BOD in water?
Biological oxygen demand directly affects the amount of dissolved oxygen in rivers and streams. The rate of oxygen consumption is affected by a number of variables: temperature, pH, the presence of certain kinds of microorganisms, and the type of organic and inorganic material in the water.
What happen if BOD is high?
The greater the BOD, the more rapidly oxygen is depleted in the stream. This means less oxygen is available to higher forms of aquatic life. The consequences of high BOD are the same as those for low dissolved oxygen: aquatic organisms become stressed, suffocate, and die.
What is the general relation between BOD and COD?
COD or Chemical Oxygen Demand is the total measurement of all chemicals (organics & in-organics) in the water / waste water; BOD is a measure of, the amount of oxygen that require for the bacteria to degrade the organic components present in water / waste water.
Does BOD increase with temperature?
The amount of oxygen that can dissolve in water (DO) depends on temperature. Also, warmer water usually will have a higher BOD level than colder water. As water temperature increases, the rate of photosynthesis by algae and other plant life in the water also increases.
Can you convert BOD to COD?
Biochemical Oxygen Demand (BOD) can be estimated from Chemical Oxygen Demand (COD) measurements, if a correlation is established. One would then multiply their COD results by this factor to estimate BOD. COD values are almost always higher than BOD values for the same sample.
What increases BOD water?
Sources of BOD Sources of biological oxygen demand include leaves and woody debris; dead plants and animals; animal manure; effluents from pulp and paper mills, wastewater treatment plants, feedlots, and food-processing plants; failing septic systems; and urban storm water runoff.
What does COD mean in wastewater?
5 Chemical oxygen demand (COD) The COD is the estimate of oxygen required for the portion of organic matter in wastewater that is subjected to oxidation and also the amount of oxygen consumed by organic matter from boiling acid potassium dichromate solution.
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.
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 is BOD explain it?
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.
How do you treat high BOD water?
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.
How is COD BOD ratio calculated?
To establish the COD:BOD ratio for your wastewater, simply have both COD and BOD run on several wastewater samples. Divide the COD concentration by the BOD concentration for each sample and average the results.
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).
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.
What are the factors that affect BOD?
Factors Affecting BOD Temperature. pH value of the water. Presence of certain kinds of microorganisms that affect the growth of the aerobic bacterias. Type of inorganic substances in water. Amount and type of organic substance in water.
How do you reduce COD in wastewater?
You can reduce COD and BOD by adding hydrogen peroxide to the wastewater solution. The hydrogen peroxide will chemically attack the organics in the wastewater, degrading them and reducing the measured COD and BOD.
Why is COD higher than BOD?
COD stands for ‘Chemical Oxygen Demand’ where BOD stands for Biochemical Oxygen Demand. COD is normally higher than BOD because more organic compounds can be chemically oxidised than biologically oxidised.
What is BOD of drinking water?
For drinking water BOD has to be less than 5 mg/L and for treated wastewater to be disposed of in the water bodies it is 30 mg/L, 100 mg/L if treated waste water is discharged into the sewerage system in India.
