Primary Treatment Practice Questions for Washington Level I

1. Question 1

   What is the main purpose of a **primary clarifier**?

   1. Keep incoming solids suspended by continuous mixing
   2. Allow settleable solids to sink for removal
   3. Add oxygen for microorganisms to treat wastewater
   4. Separate biological solids after aeration
   Show the answer

   Answer: B. Allow settleable solids to sink for removal

   A primary clarifier slows wastewater so readily settleable solids sink and can be removed as primary sludge.

2. Question 2

   What is the main purpose of primary clarification?

   1. To remove settleable and floatable solids
   2. To convert ammonia into nitrate
   3. To destroy organisms with ultraviolet light
   4. To dry sludge before disposal
   Show the answer

   Answer: A. To remove settleable and floatable solids

   Primary clarification separates solids that settle to the bottom and material that floats to the surface.

Operator Master has 2 Level I primary treatment questions, free, with an explanation after every answer.

• Plant Operations53 questions
• Math and Calculations10 questions
• Pumps and Hydraulics8 questions
• Secondary Clarification5 questions
• Biological Treatment4 questions
• Headworks and Screening4 questions
• Grit Removal2 questions
• Laboratory2 questions