It is found that ozone reaction in water nearly follows first-order kinetics in ozone concentration decreases by 50% in 12 minutes (t1/2 = 12 min). A water supplier wants to inject ozone into a pipe bringing water to thee water treatment plant to pre-disinfect the influent. The 3 ft diameter pipe is 3400 feet long with a steady flow rate of 10000 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 mg/L at the pipe's exit into the plant?