A surface treatment plant at a winter resort city has been designed to process cold, low turbidity water by direct filtration. The temperature is 10°C and the pH = 7.4. At the critical flow of 3 mgd, the t10is 90 min.
What concentration of chlorine is required at the end of the tank to ensure compliance with the EPA? (You will need to extrapolate to get Ct for pH = 7.4 and guess a chlorine concentration and then re-adjust your Ct requirement to solve for the final concentration...)
What concentration would be required if you used chlorine dioxide instead?