WTO - Water Treatment Operator Source Water Characteristics Questions and Answers

Question 1

A water treatment plant operator observes a sudden increase in turbidity in the raw water from a river source after a heavy rainfall.
Which of the following is the MOST significant and immediate operational concern related to this change?

Accepted Answer

A reduced effectiveness of the disinfection process.

Answer

A decrease in water temperature affecting chemical reaction rates.

Answer

An increase in dissolved oxygen levels impacting aquatic life.

Answer

A sudden drop in the pH of the source water.

Question 2

Which of the following BEST describes the primary cause of 'hardness' in a source water supply?

Accepted Answer

Dissolved mineral salts, primarily calcium and magnesium.

Answer

High concentrations of sodium and potassium.

Answer

The presence of dissolved organic compounds.

Answer

Low pH and high acidity.

Question 3

A groundwater well is showing consistently high levels of iron and manganese. Which physical characteristics would an operator most likely observe in the water before treatment?

Accepted Answer

Reddish-brown or black staining and a metallic taste.

Answer

A noticeable 'rotten egg' odor.

Answer

High levels of suspended solids and cloudiness.

Answer

A salty taste and high conductivity.

Question 4

What does a high alkalinity measurement in source water indicate about its chemical characteristics?

Accepted Answer

The water is likely to be very soft.

Answer

The water is highly acidic and corrosive.

Answer

The water has a low concentration of dissolved minerals.

Answer

The water has a high capacity to neutralize acids.

Question 5

A water utility is using a surface water reservoir as its source. Which of the following biological contaminants are of greatest concern for requiring filtration and disinfection treatment, especially in surface water?

Accepted Answer

Viruses and protozoa like Giardia and Cryptosporidium.

Answer

Iron bacteria and sulfur-reducing bacteria.

Answer

Algae and aquatic plants.

Answer

Total dissolved solids (TDS).

Question 6

An operator at a plant using river water notices an increase in musty and earthy tastes and odors. Which source water characteristic is the most likely cause?

Accepted Answer

An algal bloom.

Answer

Increased water hardness.

Answer

A drop in water temperature.

Answer

High levels of iron.

A water treatment plant operator observes a sudden increase in turbidity in the raw water from a river source after a heavy rainfall.Which of the following is the MOST significant and immediate operational concern related to this change?

A water treatment plant operator observes a sudden increase in turbidity in the raw water from a river source after a heavy rainfall.
Which of the following is the MOST significant and immediate operational concern related to this change?