Question

1. what is cryptosporidium not resistant to?

a. ozone
b. chlorine dioxide
c. chlorine
d. both a & b
e.

1. the removal and inactivation requirement for giardia is?

a. 99.9 %
b. 99.99 %
c. 99.00 %
d. 90%

1. if a coliform test is positive, how many repeat samples are required at a minimum?

a. none
b. 1
c. 3
d. depends on the severity of the positive sample

1. your water system takes 75 coliform tests per month. this month there were 6 positive samples. what is the percentage of samples which tested positive? did your system violate regulations?

a. 3% yes
b. 5 % no
c. 8 % yes
d. 10 % no

Explanation:

1. Cryptosporidium is highly resistant to chlorine, but ozone and chlorine dioxide are effective at inactivating it, so it is not resistant to both.
2. Standard water treatment requirements specify a 99.9% (3-log) removal/inactivation for Giardia.
3. When a coliform test is positive, the minimum requirement is to collect 1 repeat sample to confirm the result.
4. Calculate the positive percentage: $\frac{6}{75} \times 100 = 8\%$. Regulatory limits typically allow no more than 5% positive samples per month, so 8% violates regulations.

Answer:

1. d. Both A & B
2. a. 99.9 %
3. b. 1
4. c. 8 % Yes