1. A college bar with volume 500 m3 has 50 smokers in it, each smoking two cigarettes per hour. An individual cigarette emits, among other things, about 1.4 mg of formaldehyde (HCHO). Formaldehyde converts to carbon dioxide with a reaction rate coefficient of k = 0.40 hr-1 . Fresh air enters the bar at the rate of 1000 m3 /hr, and stale air leaves at the same rate. Assuming complete mixing, estimate the steady-state concentration of formaldehyde in the air. (Ans: 0.117 mg/m3 ).
2. Consider a 10 x 106 m3 lake fed by a polluted stream with a flow rate of 5 m3 /s and a pollutant concentration of 10 mg/L. There is also a sewage outfall that discharges 0.5 m3 /s of wastewater with a pollutant concentration of 100 mg/L directly into the lake. Stream and sewage wastes have a reaction rate coefficient of 12% per day. Find the steady-state, effluent pollutant concentration and flow rate.
Just want to know how to solve these questions.