What does the ratio of BOD to COD indicate?
If the BOD/COD ratio for untreated wastewater is 0.5 or greater, the waste is considered to be easily treatable by biological means. If the ratio is below about 0.3, either the waste may have some toxic components or acclimated microoorganisms may be required in its stabilization.
What does a high value of COD indicate?
1.1 Chemical Oxygen Demand. COD is an indicative measurement of the amount of oxygen that can be consumed by reactions in a measured solution. COD detection can be used to easily quantify the amount of organics in water. The higher the COD value, the more serious the pollution of organic matter by water.
What is the significance of COD in relation to the organic matter present in any natural water sample?
COD is a measure of the oxygen equivalent of the organic matter in a water sample that is susceptible to oxidation by a strong chemical oxidant. COD is widely used as a measure of the susceptibility to oxidation of the organic and inorganic materials present in water bodies and in the municipal and industrial wastes.
What is the relationship between the COD and BOD values in wastewater?
The only relation between COD & BOD is – COD > BOD. For most industrial process waste water, community sewage, drains and even some hetrogeneous sources, COD/BOD ratio has been found to be in a defined range and hence, COD result gives more or less BOD value range for such identifiable waste water.
Why the value of COD is 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 would cause a high BOD in wastewater?
BOD represents the amount of organic matter in a water supply; therefore, it increases when decaying plants, human or animal waste, and other organic compounds are added to water.