Water and wastewater treatment Flashcards
Corrective actions to be taken in response to adverse results can be found in
- Regulation 170/03 (Drinking Water Systems)
- Ontario Water Resources Act (OWRA)
- Regulation 242/05 (Compliance and Enforcement Regulation)
- None of the above
Regulation 170/03 (Drinking Water Systems)
Samples confirmed in the presence-absence test must also be tested for
- Shigella
- Salmonella
- Escherichia coli
- Giardia lamblia
Escherichia coli
How many coliform positive samples are allowed each for water systems that collect less than 40 samples per month?
- 1
- 3
- 4
- 2
1
If a water sample tests positive for coliforms, the system must collect a set of repeat samples within
- 36 hours
- 18 hours
- 48 hours
- 24 hours
24 hours
Water systems are required to achieve at least ____ removal and/or inactivation of viruses between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer.
- 2.5 log
- 3 log
- 4 log
- 2 log
4 log
Which Ontario Act is the main legislation governing drinking water in Ontario?
- Environmental Bill of Rights Act
- Sustainable Water and Sewage Systems Act
- Ontario Water Resources Act
- Safe Drinking Water Act
Safe Drinking Water Act
It is the hardest to kill the organism that causes which of the following illnesses?
- infection hepatitis
- cryptosporidiosis
- typhoid
- cholera
cryptosporidiosis
Giardia lamblia species are
- protozoans
- viruses
- bacteria
- metazoans
protozoans
Which is/are the ideal indicator for pathogens?
- Salmonella species
- Coliform group bacteria
- Gram-negative coccibacilli
- Gram-negative cocci
Coliform group bacteria
What is the main purpose of the Safe Drinking Water Act?
- Sample and test drinking water
- Supervise drinking water systems
- Protect human health
- Certify operators
Protect human health
Convert 4.5 ft to meters.
- 1.4 m
- 15 m
- 3.7 m
- 4.5 m
1.4 m
Convert 32 m² to square feet.
- 3785 ft²
- 345 ft²
- 32 ft²
- 3.0 ft²
345 ft²
Convert 35.1 cfs to gpm. • 18 300 gpm • 15 800 gpm • 17 600 gpm • 14 200 gpm
15 800 gpm
Flow through a channel 5.8 ft wide is 20.3 cfs. If the velocity is 1.4 ft/sec, how deep is the water in the channel? • 2.3 ft • 2.9 ft • 2.5 ft • 2.7 ft
2.5 ft
Determine the circumference of a clarifier, given that the radius is 95 ft. • 600 ft • 500 ft • 300 ft • 400 ft
600 ft
Convert 7.7 million gallons per day (mgd) into cubic feet per second (cfs). • 15 cfs • 10 cfs • 19cfs • 12 cfs
12 cfs
Determine the volume (in gallons) for a pipe completely full of water given the following data: diameter = 1.5 feet, length = 1.09 miles
- 65 000 gal
- 68 000 gal
- 74 000 gal
- 76 000 gal
76 000 gal
Calculate the area of a circular reservoir with a diameter of 411 ft in square feet (ft²). • 125 000 ft² • 133 000 ft² • 112 000 ft² • 108 000 ft²
133 000 ft²
Calculate 81.5% of 316. • 232 • 258 • 219 • 267
258
Convert 68°F to °C. • 37°C • 20°C • 65°C • 45°C
20°C
Which method can be used to control scale and corrosion? • sequestering • chelation • softening • pH and alkalinity adjustment with lime
pH and alkalinity adjustment with lime
The corrosion process can be accelerated by certain bacterial organisms because they produce which chemical?
- N2
- CO2
- CaCO3
- MgCO3
CO2
Loss of pressure due to friction in a pipeline is caused by
• roughness of the inside of the pipe
• difference in elevation from pipe inlet to outlet
• steepness of pipe slope
• diameter of the pipe
roughness of the inside of the pipe
An example of mechanical cleaning of distribution pipes includes • swabbing or pigging • increasing the flow rate • wet tapping • flushing
swabbing or pigging
What is the recommended minimum water pressure in a distribution system at any time, including fire flow conditions? • 30 psi or 207 kPa • 15 psi or 103 kPa • 40 psi or 276 kPa • 20 psi or 138 kPa
20 psi or 138 kPa
What is the pressure (in lb/ft²) 189 ft below a lake's surface is the lake is 386 ft in depth? • 11 789 lb/ft² • 11 791 lb/ft² • 11 793 lb/ft² • 11 800 lb/ft²
11 789 lb/ft²
What is the colour of oxidized iron? • red-brown • dark brown • red • yellow
red-brown
A channel (1.5 m wide) has water flowing to a depth of 0.75 m. What is the daily flow in the channel if the velocity of the water is 0.6 m/s? • 1440 L/min • 0.675 m³/s • 58 320 m³/d • 64 800 L/d
0.675 m³/s
A lake is 107 ft deep. Which is the psi on the bottom? • 45.6 psi • 46.3 psi • 45.2 psi • 44.8 psi
46.3 psi
Most of the carbon dioxide in groundwater originates from • plant respiration • biological oxidation of organic matter • animal respiration • weathering rocks
cadmium
A public water system that uses surface water or grroundwater under direct influence of surface water and provides filtration treatment is required by the primary agency to report an acute violation of the filtered water turbidity if any turbidity measurement collected during the month exceeds • 0.3 NTU • 2.0 NTU • 5.0 NTU • 3.0 NTU
5.0 NTU
Why are zebra mussels important?
• They cannot be consumed by humans.
• They adhere to water intakes and create blockages.
• They release a toxic substance in the distribution system.
• All of the above.
They adhere to water intakes and create blockages.
Which metal, if in contact with cast iron, would become the most active (anode)? • aluminum • cadmium • zinc • mild steel
cadmium
What does GUDI stand for?
• Ground Water Under the Direct Influence
• Good Underground Water Distribution Integration
• General Underground Distribution Interface
• Gudi Padwa is a spring-time festival celebration for some Hindus to celebrate the new year.
Ground Water Under the Direct Influence
How can groundwater become contaminated?
• fuel, solvents, pesticides, and other chemical spills
• leakage from manure storage, septic tanks, and landfills
• leaking underground and aboveground fuel storage tanks
• all of the above
all of the above
Groundwater pH is generally • exactly 7.0 • between 4.0 to 6.0 • between 6.0 to 8.5 • between 8.5 to 9.5
between 6.0 to 8.5
Which type of algae would most likely be found in nutrient-rich waters? • diatoms • blue-green algae • green algae • brown algae
blue-green algae
Which regulation pertains to the construction, operation, maintenance, and abandonment of water wells? • O. Reg. 170/03 • O. Reg. 169/03 • O. Reg. 248/03 • O. Reg. 903/90
O. Reg. 903/90
A benefit of water conservation would be
• reduced demand on supply source
• loss of revenue for the utility
• difficulty dealing with drought conditions
• possible stimulation of water service growth
reduced demand on supply source
What is the minimum treatment process required for a GUDI well?
• only chemically-assisted filtration
• physical filtration and 2-log removal of Crypto, 3-log removal of Giardia, and 4-log removal of viruses
• chemical-assisted filtraition and 2-log removal of Crypto, 3-log removal of Giardia, and 4-log removal of viruses
• only physical filtration
chemical-assisted filtraition and 2-log removal of Crypto, 3-log removal of Giardia, and 4-log removal of viruses
Water that is too soft will cause • Carbonate scale • Soap scum • Water spots • Calcium scale
Water spots
A benefit of water conservation would be
• Reduced demand on supply source
• Difficulty dealing with drought conditions
• Loss of revenue for the utility
• Possible stimulation of water service growth
Reduced demand on supply source
Which chemical will decrease alkalinity? • Silicates • Carbon dioxide • Sodium hydroxide • Sodium bicarbonate
Carbon dioxide
Which are the two principal chemicals that cause water hardness? • Calcium and magnesium • Alminum and iron • Alminum and calcium • Iron and manganese
Calcium and magnesium
At which temperature does the maximum density of water occur? • -0.4°C • 0.4°C • 4.0°C • 0.0°C
4.0°C
Which will increase pH, hardness, and alkalinity? • Sodium hydroxide • Sodium zinc phosphate • Lime • Zinc orthophosphate
Lime
Which water quality complaint is the most common for most utilities? • Stained laundry and plumbing fixtures • Appearance of the water • Illness caused by the water • Taste and odours
Taste and odours
Conductivity (as it pertains to water) is
• The measure of a solution’s ionic strength and an indirect measure of the total dissolved solids
• The measure of the electrical strength, and is directly proportional to the number of free electrons in the water
• The measure of the positive and negative metal ions in water
• The measure of ions in the water, and is directly proportional to the number of free electrons in solution
The measure of ions in the water, and is directly proportional to the number of free electrons in solution
Low values for which water characteristic may require the addition of lime, caustic soda, or sodium bicarbonate? • Water temperature • Alkalinity • Turbidity • pH
Alkalinity
The specific gravity of water is based on using a temperature of • 4.0°C • 25.0°C • 0.0°C • 20.0°C
4.0°C
Acids, bases, and salts lacking carbon are • organic compounds • inorganic compounds • aldehydes • ketones
inorganic compounds
A critical component when sampling for volatile organic compounds is to
• rinse the container before sampling
• ensure the tap is well flamed prior to use
• fill in a light-sensitive container
• ensure that there is no headspace in the sample bottle
ensure that there is no headspace in the sample bottle
When collecting a bacteriological sample, if the operator opens the bottle and drops it on the ground, which of the following statements best describes the action to take:
• the sample bottle may be rinsed and used again
• resample with a new sample bottle
• note the bottle being dropped in the comments section of the COC form
• add sodium thiosulfate and refill the bottle
resample with a new sample bottle
Which type of sample should always be collected for determining the presence of coliform bacteria? • proportional • grab sample • time composite • composite
grab sample
Which chemical is used to remove residual chlorine from water? • NaOCl • Na2SiO3 • Na2S2O3 • Na2SiF6
Na2S2O3
Which of the following is an adverse water indicator?
• colour analyzer in the distribution system has been offline for one hour due to equipment calibration
• customer complaints of a brownish colour in the water
• an indication that water has not been properly disinfected according to the Procedure of Disinfection of Drinking Water in Ontario
• pressure of 20 psi in the distribution system
an indication that water has not been properly disinfected according to the Procedure of Disinfection of Drinking Water in Ontario
What information can be found on an SDS?
• information on how to optimize the chemical’s dosage in the process
• handling and safety information about the chemical
• the MAC for the chemical in drinking water
• the method for including the substance in the facility’s Quality Management System
handling and safety information about the chemical
The ODWQS limit for trihalomethanes in a distribution water sample is based upon
• a running annual average of quarterly samples taken from a distant point in the distribution system
• a sample taken at the treatment plant intake
• a sample taken at the clear well
• a single grab sample taken from a distant point in the distribution system
a running annual average of quarterly samples taken from a distant point in the distribution system
Under the Safe Water Drinking Act (2002), adverse results obtained from drinking water treatment samples must be immediately reported. Which of the following must be notified immediately when an adverse water indicator has been identified?
• ORO and MOH
• MOH and supervisor
• MOH and MOECC and the owner of the system
• supervisor and MOECC
MOH and MOECC and the owner of the system
According to O. Reg. 170/03, a raw water sample for a large municipal residential system must be sampled for
• HPC and free chlorine
• E. coli and free chlorine
• E. coli and total coliforms
• total chlorine, free chlorine, and turbidity
E. coli and total coliforms
When a chlorine cylinder or container is charged, a new gasket should be used • every time • after 2 uses • after 3 uses • after 4 uses
every time
Chlorine storage rooms should
• have sealed walls and doors that open inwards
• be fitted with chlorine-resistant power exhaust fans ducted out at ceiling level
• have a window in the door so an operator can look into the form to detect any abnormal conditions
• have lights and fans on the inside and wired to the same switch
have a window in the door so an operator can look iinto the form to detect any abnormal conditions
What colour is liquid chlorine? • amber • yellow • dark green • light brown
amber
Which chemical could cause pink water problems? • bromine • iodine • potassium permanganate • chloramines
potassium permanganate
Which of the following shows the correct relative strengths of chlorine species as disinfectants? • OCl > HOCl > NH2Cl > HCl • HCl > HOCl > OCl > NH2Cl • NH2Cl > HCl > HOCl > OCl • HOCl > OCl > NH2Cl > HCl
HOCl > OCl > NH2Cl > HCl
What type of chlorine gas feeder is most commonly used? • combination pressure and vacuum • vacuum • combination water and pressure • pressure
vacuum
What is the primary drawback for facilities that use UV light to disinfect water?
• There is potential for the light bulbs to be coated with light-obscuring material, preventing the UV light from killing microorganisms.
• Dissolved colloids can shield microorganisms from the UV light.
• It has the potential to produce trihalomethanes.
• It does not inactivate all microorganisms.
There is potential for the light bulbs to be coated with light-obscuring material, preventing the UV light from killing microorganisms.
Which disinfect would work best against Cryptosporidium? • hypochlorous acid • chlorine dioxide • dichloramine • ozone
ozone
CTs are based on
• Concentration of chlorine, contact time, pH, and water impurities
• Concentration of chlorine, contact time, alkalinity, pH, and temperature
• Concentration of chlorine, contact time, and pH
• Concentration of chlorine, contact time, pH, and temperature
Concentration of chlorine, contact time, pH, and temperature
Chlorine is advantageous over chloramines in that chlorine • has a long history of use • is a much stronger oxidant • has a persistant residual • has simple feeding strategies
is a much stronger oxidant
Dissolved air flotation is particularly good for removing • inorganics • algae • manganese and iron • sulfides
sulfides
What is the most effective disinfectant for inactivating bacteria? • hypochlorous acid • hypochlorite ion • chloramines • bromine
hypochlorous acid
If the percentage of chlorine delivered to a water treatment plant in liquid form is 12.5% chlorine, which chemical is most likely being used? • sodium hypochlorite • calcium hypochlorite • chlorine dioxide • chlorine
sodium hypochlorite
Which high rate process uses microsand? • Actiflo process • superpulsators • tube settlers • dissolved air flotation
Actiflo process
What is the most important reason to reduce turbidity?
• to remove pathogens
• to reduce corrosion
• to reduce taste and odour problems
• to determine the efficiency of coagulation and flocculation
to remove pathogens
