WASTEWATER TREATMENT OPERATOR CERTIFICATION

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WASTEWATER TREATMENT OPERATOR CERTIFICATION

TEST #1

Actual Qs and Ans - Expert-Verified Explanation -Guaranteed passing score -80 Questions and Answers

-Format: Multiple-choice / Flashcard

Question 1: If a primary clarifier is placed out of service, then how should a plant with at least two trickling filters operate the system?

• Operate the filters in parallel
• Divert the influent to several trickling filters
• Operate the filters in series
• Maintain existing operation without changing filter arrangement

Answer:

• Operate the filters in series (v.1 pg 191)

Question 2: Which of the following is one of the basic rules of laboratory work?

• Do not leave keys in equipment or vehicles at any time
• Patrol the facilities frequently, and look for suspicious activity or behavior
• never pipet hazardous material with your mouth, even if the pipet has be sterilized
• Lock out and tag out relevant mechanical and electrical equipment before starting any

maintenance activity.

Answer:

• never pipet hazardous material with your mouth, even if the pipet has be sterilized (v.2 pg 493)

Question 3: What could happen if the digester gas is mixed with air (85 to 95% by volume)?

• Cause an explosion
• Improve efficiency of digestion
• The bacteria will become aerobic and increase VSR
• The digester becomes safer to operate due to less toxic gas in the system

Answer:

• Cause an explosion (v.2 pg 158)

Question 4: How often should the sludge at the bottom of a clarifier be pumped?

• Once a week
• Bi-weekly
• Frequently throughout the day
• Once every three days

Answer:

• Frequently throughout the day (v.1 pg 130)

Question 5: What is common practice in an activated sludge process?

• Waste all activated sludge
• Sludge age of 14 days for conventional system
• Recirculate activated sludge (RAS)
• Limiting DO to increase the mircoorganism population

Answer:

• Recirculate activated sludge (RAS) (v.2 pg 20,21)

Question 6: What is equivalent to organic solids?

• Volatile Solids
• Fixed Solids
• Suspended Solids
• Colloids

Answer:

• Volatile Solids (v.1 pg 546)

Question 7: What will the addition of chlorine gas do to the pH of wastewater?

• Moderately increase pH
• pH will not be affected
• Significantly increase the pH
• Decrease the pH

Answer:

• Decrease the pH (v.1 pg 349-350)

Question 8: Which of the following is true about trickling filters?

• It is mostly an anaerobic process
• The three main parts of a trickling filter are media, distribution system, and underdrain
• In computing BOD loading, it is standard practice to include the BOD of the re-circulated

effluent

• Filter ponding is usually due to inadequate organic loading

Answer:

• The three main parts of a trickling filter are media, distribution system, and underdrain (v.1 pg 169)

Question 9: Why should sludge at the bottom of a clarifier be removed in a timely manner?

• To improve the performance of the grit channel
• To maintain a consistent volume of sludge in the drying bed
• To minimize the formation of Chloramines
• To prevent sludge gasification, which causes the sludge to float

Answer:

• To prevent sludge gasification, which causes the sludge to float (v.1 pg 130)

Question 10: What is the purpose of the grit channel?

• Remove dissolved and non-settleable organics
• Remove heavy inorganic wastes
• To allow activated sludge to settle
• Remove substances that float and readily settle from the wastewater as part of primary

treatment

Answer:

• Remove heavy inorganic wastes (v.1 pg 84)

Question 11: What does black sludge at the bottom of a secondary clarifier located downstream of a trickling filter signify?

• Pumping rate is excessive
• Pumping duration is too long
• Detention time is too short
• Sludge has stayed in the secondary clarifier too long

Answer:

• Sludge has stayed in the secondary clarifier too long (v.1 pg 138)