Question
Download Solution PDFThe following data pertains to a sewage sample at a point source.
Initial dissolved oxygen (DO) = 12 mg/I; Final DO = 4 mg/I; Dilution of sewage was done to 2% .
The Bio-chemical oxygen demand (BOD) of the given sample of sewage is:
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFConcept:
BOD is defined as the amount of oxygen demanded by microorganisms to decompose biodegradable organic matter present in wastewater under anaerobic conditions.
BOD is the measure of the strength of wastewater.
Within 5 days 60 – 70 % of organic content is oxidized.
Therefore 5 day BOD is taken as the standard reference
\(BOD = \left( {Initial\;BOD\; - Final\;BOD} \right) \times Dilution\;Factor\)
Calculation:
Given Initial DO = 12 mg/l
Final DO = 4 mg/l
2 % Dilution sample, ∴ Dilution factor = 100/2
\(BO{D_5} = \left( {12 - 4} \right) \times \frac{{100}}{2}\)
∴ BOD5 = 400 mg/l
Last updated on May 28, 2025
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