Chlorination is the usual method for disinfecting water.

a. Name the two parameters that control the extent of disinfection.

b. Why is it necessary to guard against an overdose of chlorine?

c. Assume that disinfection with chlorine follows a first-order reaction (the disinfection rate has a direct relation to its concentration). In a chlorinated water sample containing 1. 0 mg/L chlorine, the initial concentration of viable bacteria is 100,000/mL. At the end of a 5-minute contact time, the number of viable bacteria has decreased to 10/mL. What effect would a contact time of 10 minutes have on the bacteria count?