1.In Chlorine disinfection (3-log reduction in Giardia- Cysts), determine the water pH for a contact time of 90 minutes using a chlorine concentration of 2 mg/L at 20 degrees C
2.The settling velocity of alum floc in a sedimentation basin is approximately 0.0014 fps. Calculate the equivalent overflow rate in gpd/ft2. What is the minimum detention time in hours to settle out the alum floc in an ideal basin with a depth of 10 ft.
3.Characterize the risk for a chronic daily exposure by the water pathway (oral) of 1.43 x10^-4mg/kg/d of tetrachloroethylene, 1.43 x 10^-3 mg/kg/d of arsenic, and 1.2 x 10^-4 mg/kg/d of cadmium.