If Biochemical oxygen demand (BOD) of a town is 20000 kg/day and BOD per capita per day is 0.05 kg, then population equivalent of town is_________________?
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Answer: D. 400000
Explanation
Population equivalent is calculated by dividing total municipal biological oxygen demand per day by per capita demand. Dividing twenty thousand kilograms per day by zero point zero five kilograms per capita yields four hundred thousand. This metric standardizes industrial and municipal waste loads into an equivalent population number. Biological oxygen demand measures the amount of dissolved oxygen needed by aerobic organisms to break down organic waste. Per capita BOD contribution is a standard regional baseline used to estimate domestic waste generation rates. The population equivalent formula equates industrial organic discharge to standard residential sewage loads.
Sanitary engineers use population equivalents to design municipal wastewater treatment plant capacity requirements. Industrial facilities often pay sewer surcharges based on their calculated population equivalent waste load. Accurate waste load estimation prevents overloading biological treatment reactors and protects receiving water bodies. One thousand is an incorrect arithmetic result caused by misplacing decimal points in the division step. Four thousand represents a severe underestimation resulting from incorrect division of the total BOD load. One hundred thousand fails to apply the correct mathematical ratio between total BOD and per capita contribution.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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