Biochemical Oxygen Demand 5 Test

Biochemical Oxygen Demand 5 Test

Biochemical Oxygen Demand 5 Test
The testis performed to find the amount of biologically active matter present and the rate at which the biologically active matter will be stabilised.

The BOD5 test is the primary method for determining the strength of waste water to be treated by a biological process and the strength of effluents in terms of the load on the oxygen resources of the receiving waters. The BOD test as used for assessing the efficiency of waste water treatment, is intended to be a measure of some fraction of carbonaceous oxygen demand, that is the oxygen consumed by heterotrophic microbes which utilise the organic matter of the waste in their metabolism, and not the oxygen demand exerted by autotrophic nitrifying bacteria.

Since ammonia is usually present in waste waters, nitrification inhibitors must be used to suppress the exertion of nitrogenous oxygen demand. Carbonaceous oxygen demand is called first stage BOD and nitrogenous oxygen demand is called second stage BOD.

BOD is aerobic in nature. In this we can see some of the bacterial transformations related to BOD.

new-bacterial-cells
The population of bacteria first increases and later decreases because there is food problem.

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