Determine BODཏ, if 2% is used from sewage of 5days at 20°C.

Problem. If 2% solution is used from sewage of 5 days at 20°C & dissolved oxygen depletion was 5 ppm, determine BOD₅?
Exam Name:  PGCB 2017. 



We Know that,
         BOD₅= {(D_1─ D₂)/P}
 
Here, D₁ =Initial sample dissolved oxygen
          D₂ =Final sample dissolved oxygen
          So, (D_1─ D₂)= 5                                  
          P = Volumetric sample of fraction used
             = 2%
             =0.02

        BOD₅ = ( 5/0.02)                           
                   =250 ppm
                   =250mg/l


Answer: 250mg/l
   
          

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