CWS Iron, Manganese & Hydrogen Sulfide Removal

Question 1

What is the EPA secondary maximum contaminant level (SMCL) for iron in drinking water?

Accepted Answer

0.3 mg/L

Answer

The EPA secondary MCL for iron is 0.3 mg/L; above this level, iron causes staining and aesthetic issues.

Question 2

Which odor is most characteristic of hydrogen sulfide gas in a water supply?

Accepted Answer

Rotten egg smell

Answer

Hydrogen sulfide (H2S) produces a distinctive rotten egg odor even at very low concentrations.

Question 3

Which form of iron passes through a standard sediment filter without being captured?

Accepted Answer

Ferrous iron (dissolved)

Answer

Ferrous (dissolved) iron remains in solution and cannot be filtered until it is oxidized to ferric (particulate) form.

Question 4

What is the EPA secondary maximum contaminant level (SMCL) for manganese in drinking water?

Accepted Answer

0.05 mg/L

Answer

The EPA SMCL for manganese is 0.05 mg/L; exceeding this causes black staining and undesirable taste.

Question 5

Which oxidation method is most commonly used to convert dissolved ferrous iron to filterable ferric iron?

Accepted Answer

Aeration

Answer

Aeration exposes water to oxygen, converting soluble ferrous iron into insoluble ferric iron that can then be filtered.

(CWS) Certified Water Specialist Practice Test