GATE CE 2023 Set 2 — Question 64
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Environmental Engineering → Wastewater Treatment Processes → BOD Kinetics
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Question
The theoretical aerobic oxidation of biomass () is given below:The biochemical oxidation of biomass is assumed as a first-order reaction with a rate constant of at (logarithm to base ). Neglecting the second-stage oxygen demand from its biochemical oxidation, the ratio of at to total organic carbon (TOC) of biomass is _________________________ (round off to two decimal places).[Consider the atomic weights of C, H, O and N as , , and , respectively]
Correct answer
1.8 to 2
Solution
1.Calculate the molar mass of biomass ():
2.Calculate the Total Organic Carbon (TOC) per mole of biomass:
3.Calculate the Ultimate BOD () per mole of biomass:
From the stoichiometry of the given reaction, 1 mole of biomass requires 5 moles of for complete carbonaceous oxidation.4.Calculate the 5-day BOD () at :
Using the first-order reaction formula: Given and :
5.Calculate the ratio of to TOC:
Rounding to two decimal places, the ratio is 1.82.Continue learning with Success Tracker
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