Given the discovery of chlorine-resistant pathogens, ozone is commonly used as an alternate disinfectant for drinking water. Ozone decay in water nearly follows first-order kinetics, such that its concentration decreases by half every 12 minutes (t1/2 = 12 min). A water supplier wants to inject ozone into a 4.0-ft diameter pipe that is 3,000 ft long receiving a steady water flow of 15,000 gal/min. What concentration of ozone (in mg/L) should be injected at the head of the pipe so that there will be an ozone concentration of 1.0 mg/L at the pipe’s exit? The pipe may be modeled as an ideal plug flow reactor.