Energy and Utilities Water and Wastewater Utilities 2

Question 1

What does 'BOD' stand for in wastewater treatment?

Accepted Answer

Biochemical Oxygen Demand

Answer

Biochemical Oxygen Demand (BOD) measures the amount of dissolved oxygen microbes consume when decomposing organic matter in water.

Question 2

What is 'primary treatment' in a conventional wastewater treatment plant?

Accepted Answer

Physical removal of settleable solids and floating material by screening and sedimentation

Answer

Primary treatment uses physical processes — bar screens, grit chambers, and primary clarifiers — to remove large solids and floatable material from wastewater.

Question 3

What does NPDES stand for in the context of US water regulation?

Accepted Answer

National Pollution Discharge Elimination System

Answer

The National Pollutant Discharge Elimination System (NPDES) is the EPA permit program under the Clean Water Act that controls water pollution by regulating point source discharges.

Question 4

What is 'water loss' or 'non-revenue water' in distribution system management?

Accepted Answer

Water that enters the distribution system but is not billed to customers due to leaks, theft, or metering errors

Answer

Non-revenue water is the difference between water input to the distribution system and water billed to customers, including physical losses from leaks and apparent losses from theft.

Question 5

What is the purpose of a 'water hammer' arrestor in plumbing systems?

Accepted Answer

Absorbing pressure surges from rapid valve closure to protect pipes

Answer

Water hammer arrestors use a sealed air chamber or spring piston to absorb the hydraulic shock wave created when flowing water is suddenly stopped.

Energy and Utilities Practice Test

Energy and Utilities Practice Test

Energy and Utilities Water and Wastewater Utilities 2