Plz explain ur ans in detail

Dear Student

Find the correct order below:
The ascending order of BOD is
  Paper Mill Effluent (PE) < Sewage (S) < Sugar Mill Effiuent (SE) < Distillary Effluent (DE)

Degradation of organic matter by microbes requires oxygen. 
Degree of impurity of water due to organic matter is measured in terms of biochemical oxygen demand.


More the amount of organic waste, higher will be BOD and so more will be pollution in the water body. 
This leads to extreme reduction in the dissolved oxygen and causes suffocation to the aquatic animals. 
Distillery effluent is rich in organic waste which are left from alcoholic fermentation and has highest BOD. 
Sugar mill effluent follows the distillery effluent in the concentration of organic content.
Sewage water contains the excreta and detergents mixed with it. 
Paper mill effluent has the lowest concentration of the organic mass.

Regards