How do bod and cod describe the pollution level of water?
Answers
BOD (Biologocal Oxygen Demand) means the amount of oxygen (in mg/l) microorganisms like bacteria need to 'eat' the organic polution (sugars, fat, proteins, ...). Note that not all polution can be removed (eaten) by bacteria. BOD value in polluted water is normally higher than the fresh water. Increased BOD can be resulted due to domestic sewage, petroleum residues and wastes of animals and crops.
COD (Chemical Oxygen Demand) is the amount of oxygen required to degenerate all poution in a chemical way (by adding oxidising agents and heating). In general with chemical destruction you can remove more polution than with the biological way.
As BOD is only a measurement of consumed oxygen by aquatic microorganisms to decompose or oxidize organic matter and COD refers the requirement of dissolved oxygen for the oxidation of organic and inorganic constituents both. Hence COD must be greater than BOD.
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BOD stands for Biological Oxygen demand and COD stands for Chemical Oxygen Demand.
BOD -} It is the amount of oxygen dissolved in water required by the microorganisms to decompose the organic matter present in water. The greater the amount of organic matter, the greater the BOD; and the greater the BOD, the lower the amount of dissolved oxygen available for higher animals. The BOD is therefore a reliable gauge of the organic pollution of a water body.
COD -} It stands for chemical oxygen demand. It is a method of estimating how much oxygen would be depleted from a water body as a resukt of bacterial action. BOD uses bacterial microorganisms to test the amount of oxygen in water whreas COD uses a strong chemical oxidizing agent to chemically oxidize the organic material in sample of wastewater under conditions of heat and strong acid. Thus, COD is a chemical way of determining the amount of oxygen dissolved in water.
BOD stands for Biological Oxygen demand and COD stands for Chemical Oxygen Demand.
BOD -} It is the amount of oxygen dissolved in water required by the microorganisms to decompose the organic matter present in water. The greater the amount of organic matter, the greater the BOD; and the greater the BOD, the lower the amount of dissolved oxygen available for higher animals. The BOD is therefore a reliable gauge of the organic pollution of a water body.
COD -} It stands for chemical oxygen demand. It is a method of estimating how much oxygen would be depleted from a water body as a resukt of bacterial action. BOD uses bacterial microorganisms to test the amount of oxygen in water whreas COD uses a strong chemical oxidizing agent to chemically oxidize the organic material in sample of wastewater under conditions of heat and strong acid. Thus, COD is a chemical way of determining the amount of oxygen dissolved in water.