Question

1. which does the multiple barrier treatment approach include?

a. sterilization and filtration
b. disinfection and filtration
c. disinfection and sterilization
d. infection and filtration

1. what is the maximum disinfectant residual allowed for chlorine in a water system?

a. .02 mg/l
b. 2.0 mg/l
c. 3.0 mg/l
d. 4.0 mg/l

Explanation:

For question 5: The multiple barrier water treatment approach uses sequential physical (filtration) and chemical (disinfection) steps to remove contaminants, making this the correct pairing. Sterilization is overly rigorous for standard water treatment, and infection is not a treatment step.
For question 6: Standard regulatory guidelines (such as those from the EPA) set the maximum allowable chlorine residual in drinking water systems at 2.0 mg/L to balance microbial protection and safety.

Answer:

1. b. disinfection and filtration
2. b. 2.0 mg/L