WTO Chemical Feed Systems & Dosing 3

Question 1

What is the primary purpose of a backpressure check valve installed on a chemical injection line?

Accepted Answer

To prevent process water from siphoning back into the chemical feed system

Answer

To regulate the chemical flow rate

Answer

To measure chemical feed pressure

Answer

To blend two chemicals before injection

Question 2

Which chemical is appropriate for neutralizing an acid spill in a water treatment plant chemical storage area?

Accepted Answer

Soda ash (sodium carbonate)

Answer

Sulfuric acid

Answer

Chlorine gas

Answer

Alum

Question 3

A plant must achieve a fluoride dose of 0.7 mg/L at a flow of 4 MGD. How many pounds of fluoride compound must be fed per day?

Accepted Answer

23.35 lbs/day

Answer

18.54 lbs/day

Answer

12.36 lbs/day

Answer

28.00 lbs/day

Question 4

Calcium hypochlorite (Ca(OCl)2) is best described as which type of chemical?

Accepted Answer

A granular or tablet oxidizing disinfectant

Answer

A liquid reducing agent

Answer

A pH-lowering acid

Answer

A coagulation polymer

Question 5

What is the OSHA permissible exposure limit (PEL) for chlorine gas in the workplace?

Accepted Answer

1.0 ppm (ceiling)

Answer

0.5 ppm (ceiling)

Answer

2.5 ppm (TWA)

Answer

5.0 ppm (TWA)

Question 6

Which factor most directly affects the required chemical dose for coagulation in a water treatment plant?

Accepted Answer

Source water turbidity and temperature

Answer

Plant elevation above sea level

Answer

Distribution system pump speed

Answer

Finished water storage tank level

Question 7

What is the primary regulatory purpose of maintaining a chemical feed log in a water treatment plant?

Accepted Answer

To document doses applied, verify compliance, and support regulatory reporting

Answer

To track chemical inventory for purchasing purposes only

Answer

To record equipment serial numbers and warranty dates

Answer

To measure treatment plant energy consumption