You are asked to design a disinfection process using chloramine as your disinfection agent. The influent concentration of giardia is 1000 organisms per 100 ml. The USEPA regulation requires a 3 log reduction in giardia concentration in the disinfection process. The chlorine contact tank is 30 meters long and has a cross section area of 10 square meters and the flowrate is 150 cubic meters per hour and can be modeled as a plug flow reactor. The Ct value that needed is 1100 mg/L min. It is important to know that the chloramine concentration breaks down over time due environmental factors that are beyond your control. The decay is a first order process and has a decay coefficient of 0.1 hr-1.   What is the effluent giardia concentration? In order to ensure disinfection occurs we often use the effluent concentration in our Ct calculation, what is the effluent concentration of chloramine? Given the decay behavior of chloramine described above, what concentration of chloramine should I dose this reactor with? Since the calculations above are conservative, what is the actual required dose (assuming we can predict the chloramine concentration at all times)? And how much chloramine could we actually save per day by not being conservative?

You are asked to design a disinfection process using chloramine as your disinfection agent. The influent concentration of giardia is 1000 organisms per 100 ml. The USEPA regulation requires a 3 log reduction in giardia concentration in the disinfection process. The chlorine contact tank is 30 meters long and has a cross section area of 10 square meters and the flowrate is 150 cubic meters per hour and can be modeled as a plug flow reactor. The Ct value that needed is 1100 mg/L min. It is important to know that the chloramine concentration breaks down over time due environmental factors that are beyond your control. The decay is a first order process and has a decay coefficient of 0.1 hr^-1.

1. What is the effluent giardia concentration?
2. In order to ensure disinfection occurs we often use the effluent concentration in our Ct calculation, what is the effluent concentration of chloramine?
3. Given the decay behavior of chloramine described above, what concentration of chloramine should I dose this reactor with?
4. Since the calculations above are conservative, what is the actual required dose (assuming we can predict the chloramine concentration at all times)? And how much chloramine could we actually save per day by not being conservative?