AWWA Operational Efficiency and Maintenance 4

Question 1

In asset management, what does 'remaining useful life' (RUL) help a utility determine?

Accepted Answer

When an asset should be replaced or rehabilitated to optimize lifecycle costs

Answer

The current replacement cost of an asset

Answer

The annual depreciation rate for accounting purposes

Answer

The original installation date of buried infrastructure

Question 2

What is the function of a surge tank or hydropneumatic tank in a water system?

Accepted Answer

To absorb pressure transients and protect against water hammer

Answer

To provide chemical storage for disinfection

Answer

To boost pressure in low-pressure zones

Answer

To store water for fire suppression purposes only

Question 3

A utility's O&M cost per million gallons delivered has increased steadily over three years. Which analysis would best identify the root cause?

Accepted Answer

Benchmarking against similar utilities and analyzing cost-driver subcategories

Answer

Conducting a master plan update

Answer

Increasing the customer water rates

Answer

Reducing the number of staff in the field

Question 4

What does a corrosion control program primarily aim to prevent in distribution system pipes?

Accepted Answer

Leaching of lead and copper into drinking water and pipe wall deterioration

Answer

Biological regrowth in the distribution system

Answer

Formation of disinfection byproducts

Answer

Pressure loss due to biofilm accumulation

Question 5

Which pumping efficiency improvement measure has the fastest typical payback period for most water utilities?

Accepted Answer

Upgrading to higher-efficiency motors

Answer

Replacing pump impellers to restore design clearances

Answer

Installing new pump stations

Answer

Installing parallel pipelines to reduce head loss

Question 6

When a pressure reducing valve (PRV) fails in the open position, what is the immediate risk?

Accepted Answer

Over-pressurization of the downstream pressure zone

Answer

Loss of pressure in the upstream zone

Answer

Contamination of the water supply

Answer

Increased energy consumption at pump stations

Question 7

What is the recommended maximum velocity in water distribution mains during normal operations to minimize head loss and pipe wear?

Accepted Answer

5 fps (1.5 m/s)

Answer

2 fps (0.6 m/s)

Answer

10 fps (3 m/s)

Answer

15 fps (4.6 m/s)