Waec Model Questions Vol1 2022 Chemistry Question 28
Practice objective / multiple choice question 28 from the 2022 Waec Model Questions Vol1 Chemistry examination.
A factory discharges wastewater containing a biodegradable organic pollutant at a concentration of 80 mg·L⁻¹. The discharge flow rate is 30 L·s⁻¹ into a river that flows at 1500 L·s⁻¹. The pollutant undergoes first‑order biodegradation with a rate constant k = 0.15 day⁻¹. Assuming complete mixing, the river water is sampled after a travel time of 2 days. Using the relationship BOD_t = L₀(1 - e^{-kt}) where L₀ equals the pollutant concentration (in mg·L⁻¹) at the sampling point, calculate the biochemical oxygen demand over 5 days (BOD₅) exerted by the pollutant at the sampling point. Give your answer in mg·L⁻¹ (rounded to two decimal places).
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About This Question
This is Waec Model Questions Vol1 2022 Chemistry Question 28. It is one of the objective questions from the 2022 Waec Model Questions Vol1 Chemistry examination.
Difficulty level: Hard .
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