Dean Lampman
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Wastewater Wastewater Treatment Study Material Quiz on Class C Wastewater Treatment Plant Operator Questions, created by Dean Lampman on 29/12/2017.

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Class C Wastewater Treatment Plant Operator Questions

Question 1 of 45

1

pH is the measure of

Select one of the following:

  • Amount of an acid

  • Intensity of basic or acidic condition of a liquid

  • Acidity

  • Alkalinity

Explanation

Question 2 of 45

1

The second stage of anaerobic digestion is called

Select one of the following:

  • Acid formation

  • Stabilization

  • Methane formation

  • Pathogenic formation

Explanation

Question 3 of 45

1

One liter of elemental liquid chlorine can evaporate and produce how many liters of chlorine gas

Select one of the following:

  • 100

  • 250

  • 457

  • 567

Explanation

Question 4 of 45

1

Chlorine gas is how many times heavier than air?

Select one of the following:

  • 1 times

  • 2.5 times

  • 7 times

  • 25 times

Explanation

Question 5 of 45

1

PLANT PROBLEM: Plant effluent coliform count fails to meet required standards for disinfection. Chlorine residual is normal. Disinfection supplies are not a problem.

Select one of the following:

  • Capacity of chlorinator too low

  • Too little solids in effluent

  • Contact time too short

  • Chlorine demand too high

Explanation

Question 6 of 45

1

The most important adjustments to the activated sludge process are made by adjusting

Select one of the following:

  • Aeration, pH, and RAS

  • Aeration, pH and WAS

  • RAS, WAS and aeration

  • pH, RAS and WAS

Explanation

Question 7 of 45

1

Problem: Classic sludge bulking occurring in the final clarifier of a conventional activated sludge plant. Indicators include solids pouring over the weirs, excessive floc observed at the surface, and a homogenous sludge blanket appearing throughout the clarifier. Sludge in settling test settles slowly leaving a cloudy supernatant. What is the MOST probable cause?

Select one of the following:

  • Over-oxidized sludge

  • Hydraulic washout

  • Young sludge

  • SVI too low

Explanation

Question 8 of 45

1

PROBLEM: Operational data is given below for a primary clarifier:
Influent flow: 2.5 mgd
Primary tank volume: 41,310 cubic feet

Select one of the following:

  • 0.3 hours

  • 3.0 hours

  • 13.0 hours

  • 16.8 hours

Explanation

Question 9 of 45

1

As the operator of a primary clarifier, you notice black and odorous septic wastewater leaving the clarifier. What is the probable cause?

Select one of the following:

  • Withdrawing sludge too frequently

  • Improper sludge removal

  • Excessive I&I entering WWTP

  • Excessive oil and grease entering WWTP

Explanation

Question 10 of 45

1

PROBLEM: Plant fecal coliform counts do not meet State standards. The chlorine supply is not the problem, there is adequate vacuum and chlorine feed. The chlorine contact tank has no solids build-up and the effluent flow is below design. That is the MOST likely cause?

Select one of the following:

  • High chlorine demand from excessive ammonia in effluent

  • High chlorine demand from excessive nitrate in effluent

  • High chlorine demand from excessive nitrite in effluent

  • High chlorine demand from excessive polymer in effluent

Explanation

Question 11 of 45

1

A fixed sample is

Select one of the following:

  • Not broken

  • A sample purposely 'spiked' by the lab technician for QA/QC

  • A series of composite samples

  • A sample preserved in the field upon completion

Explanation

Question 12 of 45

1

According to FDEP Chapter 62-602 FAC, an operator could have his/her license permanently revoked for

Select one of the following:

  • Falsified or misrepresented reports, logs or lab sheets

  • Cheating on an exam

  • Incompetence in operation of a wastewater treatment plant

  • Submitting false data on license application

Explanation

Question 13 of 45

1

PROBLEM: Excessive white, billowing foam in the aeration tank surface.

Select one of the following:

  • pH too high

  • MLSS too low

  • Waste temperature too high

  • WAS too low

Explanation

Question 14 of 45

1

According to Chapter 62-620 FAC, Wastewater Permitting, plant records must be maintained on-site for how many years?

Select one of the following:

  • One year

  • Three years

  • Five years

  • Forever

Explanation

Question 15 of 45

1

What happens in the stabilization (re-aeration) tank in the contact-stabilization process?

Select one of the following:

  • Adsoption of the activated floc

  • Adsorption of waste material by microorganisms

  • Agglomeration of the activated floc

  • Adsorption and digestion of the waste material collected by microorganisms

Explanation

Question 16 of 45

1

PROBLEM: Good settling in the 30 minute settleability test. Excessive floc billowing in the clarifier and washing out. Sludge scrapers and RAS system appear normal. What is the BEST solution to fix the problem?

Select one of the following:

  • Lower aeration tank effluent weirs

  • Increase RAS

  • Add chlorine to RAS

  • Reduce clarifier hydraulic loading rates.

Explanation

Question 17 of 45

1

PROBLEM: Classic sludge bulking occurring in the final clarifier of a conventional activated sludge plant. Indicators include solids pouring over the weirs, excessive floc observed at the surface, and a homogenous sludge blanket appearing throughout the clarifier. Sludge in settling test settles slowly leaving a cloudy supernatant. What is the necessary check to confirm the cause?

Select one of the following:

  • Weir over flow rate

  • Determine effluent suspended solids concentration

  • Calculate the sludge age

  • DO in the aeration tank

Explanation

Question 18 of 45

1

In a well operated activated sludge plant, when the RAS rate is decreased but the WAS rate remains constant, the expected conditions would be

Select one of the following:

  • MLSS decreases, F/M Ration increases, MCRT decreases

  • MLSS decreases, F/M Ration decreases, MCRT increases

  • MLSS increases, F/M Ration increases, MCRT decreases

  • MLSS increases, F/M Ration decreases, MCRT increases

Explanation

Question 19 of 45

1

The first step in anaerobic digestion is called

Select one of the following:

  • Acid formation

  • Stabilization

  • Methane formation

  • Alkalinity formation

Explanation

Question 20 of 45

1

A screenings dumpster is full at the headworks of the treatment plant. The dumpster is 6 ft tall, 10 ft long and 8 ft wide. How many cubic yards of screenings myst be disposed of.

Select one of the following:

  • 17.8

  • 129.6

  • 480.0

  • 575.0

Explanation

Question 21 of 45

1

The two main gases formed in the anaerobic digestion process are

Select one of the following:

  • Nitrogen and oxygen

  • Methane and oxygen

  • Methane and water

  • Methane and carbon dioxide

Explanation

Question 22 of 45

1

In an activated sludge plant, if the DO in the aeration tank suddenly decreases and the aerators are not the problem, what is the most probable cause

Select one of the following:

  • F/M Ratio decreased

  • Increased organic load into tank

  • Denitrification occuring

  • MCRT too long

Explanation

Question 23 of 45

1

How many fusible plugs can be found on a one-ton chlorine container?

Select one of the following:

  • 1

  • 2

  • 6

  • There are no fusible plugs on a one-ton container

Explanation

Question 24 of 45

1

A fire has started in the maintenance shop due to an ignition of petroleum oil. Which type of fire extinguisher should not be used to fight the fire?

Select one of the following:

  • CO2

  • Purple K

  • Pressurized water

  • Dry chemical

Explanation

Question 25 of 45

1

Mixing dry granular chlorine with petroleum products will

Select one of the following:

  • Create anhydrous chlorine dioxide

  • Create an explosive device

  • Create hydrogen dioxide

  • Create a white cloud

Explanation

Question 26 of 45

1

A confined space is defined as having a space large enough to bodily enter and perform work, has limited entry and egress and is _______________ ?

Select one of the following:

  • Not designed for continuous occupancy

  • Designed for state exam prep classes

  • Not designed to perform strenuous computer calculations

  • Designed as a long term hurricane and tornado shelter

Explanation

Question 27 of 45

1

What is the dosage of chlorine, in mg/L, if the flow being treated is 85,000 gpd and 3 pounds of chlorine are used per day?

Select one of the following:

  • 0.42 mg/L

  • 1.4 mg/L

  • 2.3 mg/L

  • 4.2 mg/L

Explanation

Question 28 of 45

1

When properly adjusted, the rope packing on a centrifugal pump is designed to leak how much?

Select one of the following:

  • One drip per second

  • One drip per hour

  • A steady, pencil sized stream should flow at all times

  • There should be NO leaks from a rope packing

Explanation

Question 29 of 45

1

In a lab, a dilute acid solution must be prepared for titration in the alkalinity test. The proper procedure for making the weak acid is to:

Select one of the following:

  • Add the water slowly to the concentrated acid to begin dilution

  • Add the water quickly to the acid to begin dilution

  • Add the acid directly to the sample without dilution

  • Add the acid slowly to the dilution water

Explanation

Question 30 of 45

1

What is the removal efficiency of the solids contact/trickling filter process if the influent TSS is 439 mg/L and the plant effluent TSS is 4.0 mg/L?

Select one of the following:

  • 4%

  • 40%

  • 89%

  • 99%

Explanation

Question 31 of 45

1

As an operator of a gravity thickener, you notice floating sludge rising throughout the thickener. All of the following may be a cause for the problem EXCEPT

Select one of the following:

  • Sludge decomposing in the tank

  • Sludge collection mechanism is off

  • Insufficient sludge removal

  • Sludge blanket too low

Explanation

Question 32 of 45

1

PROBLEM: Upon arriving at the package treatment plant serving a small community, you find a uniform sludge blanket rising throughout the clarifier. A settlettling sludge leaving a clear supernatant. MLSS test results are normal, but a calculation of the SVI shows a high sludge volume indability test reveals a very slow seex. What is the MOST likely cause of the high sludge blanket ?

Select one of the following:

  • The operator has wasted too much sludge, causing a young sludge condition

  • An extreme rain event washed out the majority of the solids

  • Filamentous bacteria are causing the slow settling

  • An overdose of chlorine has killed the floc forming and filament bacteria

Explanation

Question 33 of 45

1

PROBLEM: Solids are washing out of the secondary clarifier of the activated sludge
plant. Plant personnel increase the return activated sludge (RAS) flow rate,
which slows the problem temporarily, but gets worse after 30 minutes.
What is the cause of the plant problem?

Select one of the following:

  • Increasing the RAS increased the detention time in the clarifier

  • Increasing the RAS decreased the detention time in the clarifier

  • Increasing the RAS increased the detention time in the aeration
    tank

  • Increasing the RAS caused the DO in the aeration tank to increase

Explanation

Question 34 of 45

1

PROBLEM: Solids are washing out of the secondary clarifier of the activated sludge plant. A settleability test shows good settling CAN occur. The MOST likely cause of the problem is:

Select one of the following:

  • High flows are entering the treatment plant

  • The RAS rate is too low

  • Denitrification is occurring in the chlorine contact tank

  • The sludge collector mechanism is rotating clockwise

Explanation

Question 35 of 45

1

PROBLEM: The chlorine residual is falling, and inspection of the 150 lb cylinder and chlorine feed equipment shows ice forming on the chlorine regulator and feed lines. The BEST method to fix the falling chlorine residual is:

Select one of the following:

  • switch over to sodium hypochlorite solution

  • place a second chlorine cylinder on-line

  • roll the cylinder so liquid is feeding instead of gas

  • place a 1500W space heater next to the cylinder to thaw the ice

Explanation

Question 36 of 45

1

The fusible plug on a chlorine cylinder is designed to:

Select one of the following:

  • Melt at 1500 degrees F

  • Prevent a dangerous vacuum from forming in the cylinder

  • Melt at 158-165 degrees F

  • Melt when placed in the direct sunlight

Explanation

Question 37 of 45

1

How many times heavier than air is methane gas?

Select one of the following:

  • 1 time

  • 2.5 times

  • 4.6 times

  • Methane is lighter than air

Explanation

Question 38 of 45

1

The combination of methane and _____________ can be very combustible?

Select one of the following:

  • Carbon monoxide

  • Carbon dioxide

  • Carbon tetrazini

  • Oxygen

Explanation

Question 39 of 45

1

A class C fire extinguisher is safe to use of what type of fire?

Select one of the following:

  • Ordinary paper, wood and trash

  • Flammable fuels

  • Electrical equipment

  • Flammable metals

Explanation

Question 40 of 45

1

F/M Ratio can be BEST be described as:

Select one of the following:

  • The pounds of CBOD applied to a pound of MLVSS

  • The amount of influent TSS applied to the aeration tank

  • The loading of solids to a trickling filter

  • The amount of soluble CBOD fed to an RBC

Explanation

Question 41 of 45

1

According to FDEP chapter 62-601, FAC, a composite sample shall be used for which test?

Select one of the following:

  • Total chlorine residual

  • Effluent CBOD

  • Effluent pH

  • Effluent fecal coliform

Explanation

Question 42 of 45

1

According to FDEP chapter 62-604.550 (a) FAC, a wastewater spill shall be verbally reported to the state warning point no later than:

Select one of the following:

  • 8 hours from discovery

  • 12 hours from discovery

  • 24 hours from discovery

  • 72 hours from discovery

Explanation

Question 43 of 45

1

According to F DEP chapter 62-600.440 (4)(b), basic disinfection is
described as:

Select one of the following:

  • A chlorine residual of 0.5 mg/L for 30 minutes at peak hourly flow

  • A chlorine residual of 1.0 mg/L for 15 minutes at peak hourly flow

  • A chlorine residual of 0.5 mg/L for 15 minutes at peak hourly flow

  • A chlorine residual of 0.5 mg/L for 30 minutes at average daily flow

Explanation

Question 44 of 45

1

According to FDEP chapter 62-600.440 (4)(c) 4, basic level disinfection, any ONE sample may not exceed how many colonies per 100 ml sample?

Select one of the following:

  • 100

  • 200

  • 500

  • 800

Explanation

Question 45 of 45

1

The preservative used for transport of the fecal coliform sample is:

Select one of the following:

  • Ice the sample for no less than 6 hours minimum

  • Ice to 4 degrees C

  • 0.5% nitric acid

  • 0.2% sulfuric acid

Explanation

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