SAC State water treatment plant operator vol 1
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266 Terms
Intrusion of seawater into groundwater basins results from _
overpumping fresh water
What is the basic objective of the operation of water treatment plants?
Ensure that people drink plenty of water each day to support healthy lifestyles
Increase water use and encourage water-intensive landscaping
Produce safe, aesthetically pleasing drinking water at a reasonable cost
Provide opportunities for professional advancement and salary increases
Produce safe, aesthetically pleasing drinking water at a reasonable cost
What is one characteristic of a community water system?
Regularly serves at least 25 full-time residents
Regularly serves at least 25 people who are not residents
Regularly serves fewer than 25 full-time residents
Regularly serves fewer than 25 of the same individuals
Regularly serves at least 25 full-time residents
Which of the following influence the size of a water treatment plant as well as the number and types of processes it uses?
Expected water rates and projected profits
Impurities in raw water and cost considerations
National average rainfall and snowpack levels
Local landscaping styles and native plant programs
Impurities in raw water and cost considerations
Which plant operating guidelines are routinely monitored by water treatment plant operators?
Equipment cleaning and painting schedules
Flows and water quality indicators
Number and frequency of public tours
Vehicle mileage and fuel usage
Flows and water quality indicators
What is one purpose of clear wells or plant storage reservoirs?
Act as a trigger for ON/OFF cycling of finished water pumps
Allow clarification of water by providing time for particulates to settle out
Allow drawdown when demands are low to perform maintenance
Provide operational storage to average out high and low flow demands
Provide operational storage to average out high and low flow demands
How would you verify the actual raw water flow rate after adjusting the pumping rate to a water treatment plant?
Check reservoir levels
Count the number of pumps in service
Read the raw water flow measuring device
Rework the flow calculations
Read the raw water flow measuring device
How are the initial selection of chemical types and anticipated feed rates for a given application in a water treatment plant usually deter-mined?
Computer modeling
Jar tests
Marble tests
Pilot-plant tests
Pilot-plant tests
What is the best source of information about dangerous chemicals?
Chemical analysis from a certified laboratory
Safety data sheets (SDS)
Trial and error tests
Verbal reports from other operators
Safety data sheets (SDS)
Which of these chemicals is one of the most dangerous common alkalies?
Calcium hydroxide
Caustic soda
Chlorine
Sodium bicarbonate
Which of these chemicals is one of the most dangerous common alkalies?
Calcium hydroxide
Caustic soda
Chlorine
Sodium bicarbonate
Caustic soda
What should you do if an operator is not breathing due to chlorine gas exposure?
Cover victim with a blanket
Flush victim's eyes with water
Perform hands-only or conventional CPR
Provide victim with milk
Perform hands-only or conventional CPR
Water samples taken to measure compliance with water quality standards are usually collected at _
entrance to the distribution system
In a water treatment plant, turbidity is commonly monitored at _, _, _, _, and _
source water, flocculation effluent, sedimentation effluent, and filter effluent
The chlorine cylinder in service has less than 1 day's chlorine supply remaining. Three 150 lb chlorine cylinders are in storage. The plant uses an average of 28 pounds of chlorine per day (lb/d). How many days' supply of chlorine is available?
13 days
14 days
15 days
16 days
16 days
The range of turbidity removal effectiveness is important because of the relationship between turbidity and _
pathogenic organisms
Federal laws include sludge from a water Treatment Plant as a _ waste that requires proper handling and disposal.
Industrial
What should an operator do promptly when a treatment process upset results in the failure to meet a specific drinking water quality standard?
Apply to EPA for a waiver
Notify appropriate local health authorities
Stop operating process
Switch sources of raw water
Notify appropriate local health authorities
If a water treatment plant must be dewatered for emergency repairs, how would you prepare for this event?
Empty all storage reservoirs before repairs
Fill all storage reservoirs by early evening
Rewrite preventive maintenance program documents
Take photos of failed equipment
Fill all storage reservoirs by early evening
What kinds of records are operators required to keep on file for specified time periods for regulatory compliance?
Annual vehicle mileage and maintenance
Breakroom and restroom cleaning schedules
'Timesheets and retirement contribution records
Water quality analysis and customer complaints
Water quality analysis and customer complaints
What is one way of keeping track of how much time and money is spent doing various types of work? Tablectronic timesheets
Operator diaries
Preventive maintenance program
Work order system
Work order system
How can energy requirements for lighting be reduced in a water treatment plant?
Keep lights on in unoccupied spaces
Light all areas of the yard
Turn off lights in unoccupied spaces
Use mercury vapor lamps
Turn off lights in unoccupied spaces
What regulations require that accurate records of water treatment plant operations be maintained?
Americans with Disabilities Act
Freedom of Information Act
Occupational Safety and Health Act
Safe Drinking Water Act
Safe Drinking Water Act
What contributes to most treatment plant accidents?
Application and knowledge of safe procedures
Availability and convenience of safety equipment
Carelessness and negligence
Plant design and construction
Carelessness and negligence
What is the responsibility of water treatment plant operators?
Avoid boil-water orders
Minimize costs of producing drinking water
Produce safe and pleasant drinking water
Successfully pass operator certification examinations
Produce safe and pleasant drinking water
What do most states require for someone to work as a water treatment plant operator?
College diploma
Driver's license
First-aid training
Operator certificate
Operator certificate
A. A condition in which atmospheric or dissolved oxygen (DO) is not present in the aquatic (water) environment.
Anaerobic
B. A condition that occurs in tanks or basins when some of the flowing water entering a tank or basin flows along a nearly direct pathway from the inlet to the outlet.
Short-Circuiting
C. A connection between a drinking (potable) water system and an unapproved water supply.
Cross-Connection
D. A substance that is poisonous to a living organism.
Toxic
E. A group of bacteria found in the intestines of warm-blooded animals (including humans) and in plants, soil, air, and water that indicate the possibility of pathogenic organisms in water.
Coliform
F. Reservoirs and lakes that are rich in nutrients and are very productive in terms of aquatic animal and plant life.
Eutrophic
G. The cloudy appearance of water caused by the presence of suspended and colloidal matter.
Turbidity
H. The gathering of a gas, liquid, or dissolved substance on the surface or interface zone of another material.
Adsorption
I. The vertical distance, height, or energy of water above a reference point.
Head
J. Water that does not contain objectionable pollution, contamination, minerals, or infective agents and is considered satisfactory for drinking.
Potable Water
What is stratification in lakes and reservoirs?
Breezes starting the circulation of surface
Formation of separate layers of temperature, plant life, or animal life
Lake turnover due to temperature changes
Uniform water temperature profile from surface to bottom
Formation of separate layers of temperature, plant life, or animal life
What causes the elevation and slope of water tables and artesian pressure levels to change?
Collection of water into a reservoir
Pollution from agricultural activities
Seasonal variations in the supply of water
Selection of intake structures
Seasonal variations in the supply of water
How extensive should the treatment be for reclaimed water?
Depends on climate conditions at point of use
Depends on potential exposure to the public
Depends on the funds available for treatment
Depends on the NPDES permit
Depends on potential exposure to the public
What are water rights?
Correct methods of treatment
Ownership of water
Permission to discharge water
Permission to use water
Permission to use water
Who should conduct a sanitary survey?
People trained in phone and in-person survey techniques
People trained in public health engineering and the epidemiology of waterborne diseases
People trained in wastewater collection and treatment
People trained in water treatment plant design and construction
People trained in public health engineering and the epidemiology of waterborne diseases
Which of the following water quality problems are not usually related to algal blooms?
Dissolved oxygen depletion
Reduced chlorination efficiency
Reduced water temperature
Taste and odor problems
Reduced water temperature
Under what circumstances are tastes and odors in a domestic water supply most noticeable?
At or above room temperature
In glass containers
In plastic containers
Near freezing
At or above room temperature
What is the impact on water treatment plants from increased organic loadings caused by algal blooms?
High trihalomethane levels
Increased chlorine demand and color
Increased public confidence in water supply
Increased water treatment costs
Increased chlorine demand and color
How can a water agency meet acceptable trihalomethane levels?
Change disinfection methods
Decrease detention time
Increase disinfection chemicals
Prechlorinate the influent
Change disinfection methods
Reservoir water quality management programs can control or eliminate what types of water quality problems?
Excessive turbidity
Frequency and intensity of algal blooms
Insufficient disinfection
Precipitation of iron and manganese
Frequency and intensity of algal blooms
How can iron, manganese, and hydrogen sulfide problems be controlled in a reservoir?
By controlling algal productivity
By improving the fishery habitat
By preventing dissolved oxygen depletion
By regulating recreational activities
By preventing dissolved oxygen depletion
How can the recreational values of a reservoir be improved by proper reservoir management?
Increase in agricultural use
Increase in chemical residuals
Reduction of access points
Reduction of algal problems
Reduction of algal problems
What is the best tool for managing watersheds?
Political process
Public hearings
Regulatory process
Voluntary compliance
Regulatory process
How can water quality problems caused by septic tank leaching systems be solved?
Increase nutrient loads to reservoirs
Install more septic tanks
Locate leaching fields within watersheds
Replace septic tanks with sewer systems
Replace septic tanks with sewer systems
The volume of a reservoir is estimated to be 9.8 acre-feet. The desired dose of copper is 0.5 mg/L and the copper content of the copper sulfate to be used is 25 percent. How many pounds of copper sulfate will be needed?
53 lb
54 lb
55 lb
56 lb
53 lb
What is destratification of a lake or reservoir?
Elimination of separate layers by algal blooms
Natural turnover during seasonal changes
Vertical mixing to eliminate separate layers of temperature, plant life, or animal life
Wind blowing across the water surface causing mixing
Vertical mixing to eliminate separate layers of temperature, plant life, or animal life
Why might complete destratification of a reservoir be undesirable?
Water may become too cold for fish
Water may become too cold for recreation
Water may become too warm for algal control
Water may become too warm for domestic use
Water may become too warm for domestic use
What water quality indicators should be monitored in domestic water supply reservoirs that develop anaerobic zones?
Biochemical oxygen demand (BOD) and turbidity
Hardness, pH, and color
Hydrogen sulfide, iron, and manganese
Total dissolved solids (IDS) and dissolved oxygen (DO)
Hydrogen sulfide, iron, and manganese
How can the entrance of silt into the intake system be minimized?
Locate intake at low point
Locate intake away from low point
Locate intake in shallow water
Locate intake near wetlands
Locate intake away from low point
What is the major advantage of multilevel intake systems in domestic water reservoirs?
Access to water with different characteristics at different depths
Decreased cost and maintenance requirements
Limited access to water during drought conditions
Little control over quality of water released downstream
Access to water with different characteristics at different depths
What is the purpose of coagulation and flocculation?
To control corrosion
To kill disease-causing organisms
To remove leaves, sticks, fish, and other debris
To remove particulate impurities
To remove particulate impurities
What is coagulation?
Clumping together of fine particles into larger particles with chemicals
Gathering together of particles by gentle stirring
Settling out particles by reducing water velocity
Solidifying large particles by evaporation
Clumping together of fine particles into larger particles with chemicals
What is flocculation?
Clumping together of fine particles into larger particles with chemicals
Gathering together of particles by gentle stirring
Settling out of particles by reducing water velocity
Solidifying large particles by evaporation
Gathering together of particles by gentle stirring
How long should the coagulation reaction last?
A few days
A few hours
A few minutes
A few seconds
A few seconds
Why are coagulant aids used?
To add density and toughness to flocs
To increase the speed of the chemical reaction
To reduce the costs of coagulants
To separate floatables from floc
To add density and toughness to flocs
What is the most commonly used coagulation chemical?
Alum
Hypochlorites
Metallic salts
Polymers
Alum
How can an operator verify the effectiveness of the coagulant chemicals and dosages being applied at the flash mixer?
Determine finished water chlorine demand
Measure raw and finished water temperatures
Measure source water turbidity levels
Perform a series of jar tests
Perform a series of jar tests
What is the disadvantage of mechanical mixers in coagulation?
Higher electricity use than other methods
Less reliable than other methods.
More expensive to purchase than other equipment
Slower mixing than other methods
Higher electricity use than other methods
What is the purpose of the flocculation process?
To create floc of good size, density, and toughness
To disinfect floc with chemicals such as metallic salts
To remove floc through sedimentation and fil- tration
To reverse the clumping that occurred during coagulation
To create floc of good size, density, and toughness
How are the proper type and amount of coagulant chemicals determined?
By conducting jar tests at least daily
By reading labels and safety data sheets (SDS)
By spot checking samples at designated sam- pling sites
By timing the total transit time through the treatment plant
By conducting jar tests at least daily
How can poor process performance be spotted early so that corrective measures can be taken?
Adjust mixer speed often to determine process changes
Monitor water quality throughout the water treatment process
Sample one water quality indicator at one point in the process
Rely on turbidity of filtered water as an indication of overall process performance
Monitor water quality throughout the water treatment process
What is the detention time (minutes) in a rectangular flocculation basin when the flow is 0.9 Mgal/d? The basin is 24 feet long, 12 feet wide, and 8 feet deep.
27 min
28 min
29 min
30 min
28 min
What is the basic purpose of the jar test?
Determine whether chemicals from suppliers meet specifications
Duplicate plant detention times and mixing and settling conditions in the laboratory
Prepare water for taste and odor trials with consumers
Test newly developed chemicals for use in treatment plants
Duplicate plant detention times and mixing and settling conditions in the laboratory
After a jar test is completed, what does a hazy settled water indicate?
Poor coagulation
Poor flocculation
Poor mixing
Poor turbidity
Poor coagulation
Which of the following factors are not important when evaluating jar test results?
Amount of floc formed
Clarity of water between floc particles
Floc settling rate
Paddle construction
Paddle construction
Determine the setting on a dry alum feeder in pounds per day when the flow is 1.2 Mgal/d. Jar tests indicate that the best alum dose is 9 mg/L.
88 lb/day
90 lb/day
92 1b/day
102 1b/day
90 lb/day
What is a desirable floc appearance?
Bluish tint
Milky appearance
Popcorn flake
Tiny alum floc
Popcorn flake
A water treatment plant used 24 pounds of cationic polymer to treat 1.4 million gallons of water during a 24-hour period. What is the polymer dosage in mg/L?
1.8 mg/L
2.0 mg/L
2.1 mg/L
2.3 mg/L
2.1 mg/L
Why should operators keep polymer powders off of floors?
They become extremely slippery when wet
They become tripping hazards when hardened
They become unsightly when dispersed
They become very sticky when stepped on
They become extremely slippery when wet
Liquid polymer is supplied to a water treatment plant as a 15 percent solution. How many gallons (gal) of liquid polymer should be mixed in a barrel with water to produce 100 gallons (gal) of 0,5 percent polymer solution?
0.03 gal
0.33 gal
33 gal
3.3 gal
3.3 gal
Which items are adjusted in the enhanced coagulation process?
Detention time and mixing
Dissolved oxygen and turbidity
pH and coagulant dosage
Total suspended solids and temperature
pH and coagulant dosage
What is the purpose of the hydrocyclones in ballasted flocculation?
To separate the dissolved solids from the water
To separate the floc from the coagulant
To separate the microsand from the sludge
To separate the sludge from the slurry
To separate the microsand from the sludge
A ballasted flocculation process has two hydro-cvclones in operation (two trains) with an influent flow of 4,000 pm and a microsand slurry recirculation rate of 300 gpm. Six V samples from the train produced the following volumes of settled microsand: 30 ml, 25 ml, 25 mL, 40 mL, 30 mL, and 30 mL. The six vol-unes of samples collected in the cone averaged 2.000 mL. Calculate Cm the microsand concentration in the tanks, in grams of microsand per liter (g/L).
1.9 g/L
2.3 g/L
2.8 g/L
3.8 g/L
3.8 g/L
Why should operators maintain a diluted feed solution in ballasted flocculation?
To maximize hydrocyclone process efficiency
To maximize inlet pressure to the hydrocyclone
To minimize microsand losses from the hydrocyclone
To minimize roping discharges at the hydrocyclone apex
To minimize microsand losses from the hydrocyclone
What is the first step in optimizing a ballasted flocculation process?
Optimize the coagulant dose
Optimize the microsand feed solution
Optimize the pH
Optimize the polymer dose
Optimize the coagulant dose
What is one purpose of presedimentation facilities?
Avoid need for sedimentation basins
Increase the concentration of suspended solids
Prevent solids settling out before sedimentation
Reduce the solids-removal load at the water treatment plant
Reduce the solids-removal load at the water treatment plant
What size particles can be removed from water by sedimentation?
0.3-0.7 microns
2-8 microns
Greater than 10 microns
Smaller than 10 microns
Greater than 10 microns
What property of alum attracts negatively charged particles?
Ease of creating alloys
Large particle size
Negative charge
Positive charge
Positive charge
What happens to the settling rate (settling velocity) of particles in water when the water temperature drops?
Decreases
Depends on weather
Increases
Stays constant
Decreases
What is the largest portion of the sedimentation basin?
Inlet zone
Outlet zone
Settling zone
Sludge zone
Settling zone
Calculate the theoretical detention time for a rectangular sedimentation basin in hours. The basin is 80 feet long, 30 feet wide, 10 feet deep, and treats a flow of 1.8 MGD.
0.24 hours
2.4 hours
24 hours
240 hours
2.4 hours
What is the major means by which operators can control water treatment processes?
Adiusting chemicals and chemical feed rates
Controlling sedimentation process
Controlling water temperatures
Modifying demands for water
Adiusting chemicals and chemical feed rates
Estimate the surface loading rate in gallons per minute per square foot for a rectangular sedimentation basin 20 feet wide and 40 feet long when the flow is 0.5 MGD.
0.21 gpm/ft2
0.43 gpm/ft2
0.64 gpm/ft2
0.86 gpm/ft2
0.43 gpm/ft2
Determine the mean flow velocity in feet per minute (ft/min) for a rectangular sedimentation basin with a flow of 2.0 MGD. The basin is 75 feet long and 25 feet wide with a depth of 14 feet.
0.18 ft/min
0.36 ft/min
0.48 ft/min
0.53 ft/min
0.53 ft/min
Determine the weir loading rate in gallons per minute per foot (gpm/ft) of weir for a rectangular sedimentation basin with a flow rate of 2.0 MGD. Four effluent launders 10.5 feet (ft) long with V.notch weirs on both sides of the launder extend into the basin from the outlet end.
16.5 gpm/ft
19.4 gpm/ft
23.2 gpm/ft
33.1 gpm/ft
16.5 gpm/ft
_ combine the coagulation, floccula- tion, and sedimentation processes in a single basin.
solids-contact process units
Sludge produced by a solids-contact clarification unit is recycled through the process to act as a _
coagulant aid
Changes in which process variables cause instabil-it in solids-contact units?
DO, chlorine demand, and pH
Color, alkalinity, and pesticides
Flow, temperature, and turbidity
Taste, odor, and microbial content
Flow, temperature, and turbidity
What does the volume over volume test result tell an operator about the solids-contact unit?
Chemical feeder setting
Clarity of supernatant
Percentage of slurry
Speed of the recirculation device
Percentage of slurry
If the raw water at a treatment plant needs a lime dose of 10.5 mg/L, determine the setting on the lime feeder in pounds per day (1b/d) when the flow is 1.5 MGD
126 lb/d
131 lb/d
154 lb/d
175 l6/d
131 lb/d
What is the primary factor in determining the frequency of sludge removal?
Rate of chemical feed
Rate of flow
Rate of sludge buildup
Rate of weir loading
Rate of sludge buildup
Low-turbidity source waters may not require _
sedimentation
Which water quality indicators should be monitored in the normal operation of the sedimentation process?
Chlorine residual and coliforms
Suspended solids and dissolved oxygen
Taste, odor, and pH
Temperature and turbidity
Temperature and turbidity
In solids-contact clarifiers, what should an operator do if the sludge blanket is of normal density but very close to the surface?
Adjust the chemical dose
Install sight glasses
Prevent short-circuiting
Waste more sludge
Waste more sludge
Note 
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