WTO Quality Monitoring 3

Question 1

What is the action level for copper under the Lead and Copper Rule that triggers additional treatment requirements?

Accepted Answer

1.3 mg/L

Answer

The action level for copper is 1.3 mg/L; if exceeded at the 90th percentile of tap samples, the system must take corrective actions including public education.

Question 2

When using the Standard Methods titration to measure total alkalinity, what indicator is typically used?

Accepted Answer

Both phenolphthalein and methyl orange or a mixed indicator

Answer

Total alkalinity titration uses phenolphthalein to the P-alkalinity endpoint (pH 8.3) and then a mixed indicator to the T-alkalinity endpoint (pH 4.5).

Question 3

A distribution system sample shows a heterotrophic plate count (HPC) of 600 CFU/mL. What does this result suggest?

Accepted Answer

There may be a loss of disinfectant residual or biological regrowth

Answer

An HPC above 500 CFU/mL suggests potential loss of disinfectant residual or biological regrowth, though HPC itself has no federal MCL.

Question 4

Under the Stage 2 DBPR, what sampling approach replaced the running annual average used in Stage 1 for TTHM and HAA5 compliance?

Accepted Answer

Locational running annual average (LRAA)

Answer

Stage 2 DBPR uses the Locational Running Annual Average (LRAA), which evaluates compliance at each individual monitoring location rather than as a system-wide average.

Question 5

What is the primary purpose of continuous turbidity monitoring at individual filter effluent in a surface water treatment plant?

Accepted Answer

To detect filter breakthrough and maintain Cryptosporidium removal credits

Answer

Individual filter effluent turbidity monitoring detects filter breakthrough early, protecting Cryptosporidium removal credits required under the LT2 Enhanced SWTR.

(WTO) Water Treatment Operator Certification Practice Test

(WTO) Water Treatment Operator Certification Practice Test

WTO Quality Monitoring 3