C Exam Practice Questions And Correct

Groundwater Treatment Operator Class C Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of a groundwater treatment plant?
• To store water for later use
• To remove contaminants from groundwater to make it safe for

drinking

• To generate electricity
• To supply water for industrial use only

Rationale: Groundwater treatment plants are designed to remove

physical, chemical, and biological contaminants to provide safe drinking water. 1 / 4

• Which of the following is a common disinfectant used in groundwater

treatment?

• Ammonia
• Chloramine
• Chlorine
• Fluoride

Rationale: Chlorine is widely used for disinfection because it

effectively kills bacteria and viruses.

• The most common method to remove iron and manganese from

groundwater is:

• Filtration only
• Oxidation followed by filtration
• Sedimentation only
• Coagulation

Rationale: Iron and manganese are typically oxidized to form

insoluble particles that can then be filtered out.

• What is the typical pH range for groundwater?

A. 3–5

B. 5–6

C. 6.5–8.5

D. 9–11

Rationale: Natural groundwater generally has a neutral to slightly

alkaline pH, which is safe for consumption. 2 / 4

• Which type of filter is commonly used in small groundwater treatment

plants?

• Pressure sand filter
• Rapid sand filter
• Membrane filter only
• Slow sand filter

Rationale: Rapid sand filters are commonly used due to their

efficiency in removing suspended solids.

• What is the primary purpose of aeration in groundwater treatment?
• To increase pH
• To remove dissolved gases like hydrogen sulfide and to oxidize

iron and manganese

• To remove bacteria
• To soften water

Rationale: Aeration introduces oxygen, which helps remove gases

and oxidizes metals for easier removal.

7. Turbidity in water is caused by:

• Dissolved salts
• Suspended particles such as silt, clay, or organic matter
• Microorganisms only
• pH variations

Rationale: Turbidity results from suspended particles that scatter

light and make water appear cloudy. 3 / 4

• What is the safe residual chlorine concentration in drinking water

distribution systems?

• 0.01–0.05 mg/L
• 0.2–0.5 mg/L
• 0.2–2.0 mg/L
• 5–10 mg/L

Rationale: Maintaining chlorine residual within this range ensures

continued disinfection without affecting taste significantly.

• How does a cartridge filter remove particles from water?
• By chemical reaction
• By physical straining
• By biological activity
• By oxidation

Rationale: Cartridge filters physically trap particles as water passes

through the filter media.

• The term “groundwater under the influence of surface water”

refers to water that:

• Has a high mineral content
• Has characteristics influenced by surface water, possibly requiring

treatment

• Is free from contamination
• Is highly acidic
• / 4