Problem 5. A sewer pipe 2 m in diameter is half full of water flowing at an average speed of 1.5m/sec with a BOD of 150 mg/L. The pipe flows

into a basin (10,000 m³ volume), which is also fed by a stormwater pipe 1 m in diameter, half-full with water, flowing at 1.0 m/sec and no BOD.The basin has a constant volume, and a single outlet. What is the steady state concentration of BOD in this outlet stream? BOD degrades as a first order kinetics in the basin of 0.9 day'.

Fig: 1