Question

Explain brief on bio chemical oxygen demand.....​

Answer 1

AnSwer :-

Biochemical Oxygen Demand (BOD) :-

It is the amount of oxygen used by the suitable microorganisms present in water during 5 days at 20°C.

The BOD values of different samples of water

➠ For pure water - 1 ppm

➠ Fairly pure water - 3 ppm

➠ Doubtful purity - 5 ppm

➠ Municipal sewage - 100 - 4000 ppm.

$\boxed{\sf BOD \propto Extent \: of \: pollution (toxic \: nature)}$

$\Large\star$ BOD greater than 17ppm indicates high Pollution and is harmful.

$\boxed{ \sf BOD = \dfrac {Wt. \: of \: O_2 (mg)}{Vol. \: of \: H_2O(lit)}}$

$\sf = \dfrac{part \: of \: oxygen}{million \: parts \: of \: sample}$

The ion exchange methods generally used for removal of bigger ions such as Cl$^-$, Mg² and Ca²

Answer 2

It is the amount of oxygen used by the suitable microorganisms present in water