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ELC Drinking Water Operator Course SSFC > ELC mid-term > Flashcards

ELC mid-term Flashcards

To study for ELC drinking water examination, in preparation for required certification as an Entry-level Drinking Water Operator

0
Q

This regulation describes which water systems need certified operators to conduct certain regulatory tasks

A

O. Reg 170/03

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1
Q

A certified operator receives training and certification under what regulation?

A

O. Reg 128/04

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2
Q

What are the responsibilities required by certified operators under the SDWA?

A

Sampling and testing of water
Make adjustments
Examine within 72 hours the test results
Take appropriate action in response to alarms
Perform combined chlorine residual, free chlorine residual, turbidity and fluoride testing
Perform regular checks on water treatment to confirm functioning

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3
Q

True or false

Except for large municipal residential systems, checks for turbidity and chlorine residual for the other 4 types of systems above can be conducted by persons other than certified operator water quality analyst if certain conditions are met

A

True

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4
Q

Failure to comply with regulations can lead to what consequences?

A

Provincially issued orders
A charge with an offence to failure to comply
Financial penalties up to 7 million for an individual, or 10 million for a corporation
Interim operation authorities can be appointed

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5
Q

Threats to source water

4 vulnerable areas in the CWA

A

Surface water intake protection zone

Wellhead protection area

Highly vulnerable aquifer

Significant groundwater recharge area

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6
Q

The minimum alarm standard for free chlorine residual

A

0.1 mg/L less than the free chlorine residual that is required to achieve primary disinfection

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7
Q

The minimum alarm standard for free chlorine residual and total chlorine residual (for the purpose of determining combined chlorine residual) in a distribution sample

A

0.25 mg/L

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8
Q

The minimum and maximum free chlorine residual in a distribution sample

A

Maximum alarm standard is N/A

Minimum is 0.05 mg/L

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10
Q

A drinking water system not using chlorination or chloramination as their primary disinfection,

must have one of the two following features installed in the system

A

A feature that ensures no water is directed to users

A feature that causes an alarm to sound in the building where disinfection occurs/ at location where person is present

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10
Q

What is the Purpose of the coagulation process?

A

the rapid dispersion of coagulation to destabilize particles

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11
Q

Adverse results of drinking water tests

A
  • Presence of bacteria
  • A result exceeding standards outlined in 169/03
  • Presence of pesticide not listed in 169/03
  • Chlorine residuals below minimum values
  • Filter effluent turbidity >1.0 NTU
  • Sodium >20mg/L
  • Exceeding an MAC for any health-related parameter
  • Fluoride >1.5 mg/L
  • Any observation indicating improper disinfection
  • Test results from continuous monitoring equipment
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12
Q

Components of a free chlorine residual

A

Hypochlorous acid

Hypochlorite ion

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13
Q

The minimum treatment required for a groundwater source

A

2-log removal/inactivation of viruses

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14
Q

The electrical treatment of 02 or dry air can generate what onsite?

A

03

ozone

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15
Q

What disinfectants can be used for secondary disinfection?

A 
Chlorine Gas
sodium hypochlorite
calcium hypochlorite
chlorine dioxide
chloramination
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16
Q

Define Turbidity

A

The cloudy appearance of water that is caused by colloids and suspended particles. Turbity is the interaction of light upon these particles.

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17
Q

True Colour vs Apparent Colour

A

True colour is the colour of water after turbidity has been removed, while apparent colour is measured in an unfiltered sample.

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18
Q

factors affecting disinfection process

A 
Dosage
temperature
mixing
pH
contact time
concentration of microorganisms
type of chemical
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19
Q

Some common sources for taste/odour

A

algae
dissolved gases
dichloramines
minerals/other compounds

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20
Q

drawbacks encountered when flushing

A

low water pressure
discoloured water
no water

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21
Q

define alkalinity

A

the buffers against sudden changes in pH.

Necessary during coagulation process

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22
Q

4 types of backflow prevention devices used to prevent backflow of non-drinking water into system

A

Vacuum breaker
Double check Detector Assembly
Pressure zone valve
2x diameter Air gap

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23
Q

Shoring must be used in a trench if it is more than _______m/ft deep

A

4 feet

1.2 m

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24
Q

What is chloramination? what type of residual is monitored during this disinfection process?

A

the addition of ammonia to chlorinated water to form monochloramines, which are a persistent residual.

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25
Q

the breakpoint in chlorination is what exactly?

A

The point in disinfection at which chlororganices and chloramines are partly destroyed and a free available residual is formed

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26
Q

O. Reg 169/03 (1,2,3)

A

The limits on health based parameters that can be present in drinking water.

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27
Q

The difference between clearwells, standpipes and elevated tanks?

A

Clearwells store treated water for continuous operation

Standpipes and elevated tanks are used for both storage, and pressure

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28
Q

the MAX, MIN and NORMAL pressures in the distribution system

A

NORMAL 40-80 psi

MIN 20 psi

MAX 100 psi

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29
Q

3 Factors that reduce shelf life of Sodium Hypochlorite

A

Concentration
light
heat

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30
Q

Pressure is defined as

A

Force per unit area

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31
Q

What is head loss?

A

pressure loss due to friction

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32
Q

Water hammer is:

a) caused by opening/closing valves slowly
b) the formation of bubbles
c) The force of water when it changes to a direction
d) the force caused by sudden change in water velocity

A

d)

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33
Q

True or False

The hydraulic grade line is the line which connects a booster pump to the storage tank

A

False

The Hydraulic Grade Line represents the residual pressure in the water main after taking into account the pressure loss due to friction

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34
Q

Thrust is:

A

The force of water when it changes to a direction

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35
Q

The products created due to the reaction of chlorine or other disinfectants with organic materials present in raw water during treatment

A

Disinfection Bi-Products (DBP)

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36
Q

True or False

Colloids usually have a negative electrical charge

A

True

Why they do not attract and settle out without coagulant

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37
Q

Name one significant impact on the disinfection process when raw water has increased temperature

A

Higher temperature increases potential formation of DBPs
Affects rate of chlorine decay
makes it more different to maintain a chlorine residual

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38
Q

what are the operational guidelines for pH in drinking water?

A

6.5-8.5

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39
Q

The regulations/guidelines that define GUDI

A

O.Reg 170/03

contains a checklist to identify groundwater sources

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40
Q

Multi-Barrier Approach

What are the 5 barriers?

A 
Source water protection
Drinking water treatment
Distribution system security
Automatic control and early warning monitoring
Responses to adverse conditions
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41
Q

The CT Concept

A

CT = Concentration (mg/L) x Time (minutes)

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42
Q

What is the minimum Treatment for Surface Water according to O.Reg 170/03

A

Chemically assisted filtration, followed by disinfection (or equivalent)

99 % (2-Log) inactivation of Cryptosporidium

  1. 9 % (3-log) inactivation of Giardia
  2. 99 % (4 log) inactivation of viruses
43
Q

3 Reasons for Secondary Disinfection

A

1) to maintain a persistent disinfection residual
2) reduce re-growth of bacteria
3) Contol Biofilm formation
4) Serve as an indicator of system integrity

44
Q

What chemicals can be used for secondary disinfection?

A

Chlorine
Chlorine Dioxide
monochloramine
(only)

45
Q

True or False

Disinfection efficiency increases with the pH

A

False

Lower ph is more efficiently treated

46
Q

When is Uv Disinfection acceptable as a primary source of treatment?

A

Non-GUDI

GUDI, only with chemically assisted filtration

47
Q

The Maximum Chlorine Residual at any time and in any location within the distribution system

A

4.0 mg/L (when measured as free chlorine)
3.0 mg/L (when measured as combined chlorine)
.8 mg/L when measured as Chlorine Dioxide

48
Q

Major Steps in Conventional Surface Water Treatment Process

A 
intake/screening
pre-disinfection
coagulation chemical addition
coagulation
flocculation
clarification (ie. sedimentation)
Filtration 
Post disinfection
clearwell storage (contact time)
High lift pumping
49
Q

Single level Intake vs. Multi level intake

A

single level: inexpensive, but subject to seasonal water quality variations (from temperature and nutrient fluctuations)

multi-level: expensive, but water can be taken from depth of best water quality at any time

50
Q

The purpose of Tube Settlers

A

increase settling efficiency by providing a higher ratio of effective surface area per volume

51
Q

Purpose of storage facilities

A 
Pressure
Reduce size of transmission mains
Firefighting
Industrial requirements
Balance fluctuating demands
52
Q

Purpose of elevated tanks

A

Maintain pressure

Eliminate need for continuous pumping

53
Q

Standpipes are storage tanks located where?

A

On ground level
Providing low pressure
Taller than diameter

54
Q

What is a surge tank?

A

Controls water hammer

Absorbs sudden a pressure to provide air brakes

55
Q

Preventing ice damage in water storage tanks can be done how

A

Varying water level 50% every 24 hrs for above ground tanks

25% every 24 hrs for underground reservoirs

Pressurizing distribution system or steam generator will aid in ice removal/prevention

56
Q

Types of piping

A 
Cast iron
Asbestos-cement
Plastic-PVC
Steel
Concrete
Others-
57
Q

How often are storage tanks cleaned and drained?

A

Inspected annually and cleaned every 3 years

58
Q

Larger diameter pipes are usually made of

A

Concrete

59
Q

3 types of plastic pipes

A

PVC
Hdpe
PB

60
Q

Tapping machines

A

Used to drill or thread holes into a pipe surface

“Wet tapping”

Ensure cutter bit is fully withdrawn

61
Q

The most accurate way to detect leaks in distribution system

A

Sound rods

62
Q

Unidirectional flushing

A

Flow of water in a single direction

63
Q

Frozen lines are thawed how?

A

Electrical thawing
Hot water
Thawing using a steam generator
“Steam Jennie”

65
Q

Types of corrosion

A

Internal pipe corrosion- tuberculation

External pipe corrosion- electrical chemical reactions and pinhole leaks or rust on outside of pipe

66
Q

Chlorine Demand =

A

Dosage-residual

67
Q

3 parameters that determine the length of a filter run. Any one of these parameters can determine when a backwash is required in the system.

A

Head loss
increase in turbidity
the filter run time

68
Q

4 different zones of a sedimentation tank

A

inlet zone
settling zone
sludge zone
outlet zone

69
Q

What is the recommended concentration of flouride in drinking water?

A

0.5-0.8 mg/L

70
Q

3 chemicals typically used for fluoridation

A

sodium flouride
hydrofluosilicid acid
sodium silicofluoride

71
Q

Common Chemical used as a coagulant in water treatment

A

Alum
Aluminum Sulphate
Al2(SO4)3

72
Q

psi x ____ = kPa

kPa / ____ = pis

A

6.895

73
Q

1m head = how much kPa?

A

9.804 kPa

74
Q

Friction loss depends upon what factors

A 
velocity
pipe diameter
length
degree of roughness
fittings/valves
75
Q

Pressure lost due to friction

A

headloss

76
Q

Occurs when absolute pressure at the pump drops below the vapour pressure of the liquid

forms vapour bubbles

A

Cavitation

77
Q

2 types of shoring

A

Timber shoring

Hydraulic aluminum shoring

78
Q

True or false

Odwqs for cyanobacterial toxin microcystin-LR is 0.0015 mg/L

A

True

79
Q

Indicator organisms are used for what

A

To determine whether or not pathogens are present in raw water

80
Q

True or false

E. coli is always an indication of fecal contamination

A

True

81
Q

True or false

Sodium hypochlorite lowers pH

A

False… It increases ph

82
Q

Addition of chlorine to an intake system ( sirface water) is usually down to control what?

A

Zebra mussels

83
Q

Direct filtration is basically conventional treatment with no ____________

A

Clarification

Non gudi

84
Q

The destabilization of particles so they can clump together and for floc

A

Coagulation

85
Q

Alkalinity and coagulant for a precipitate that captures particles, therefore…

A

Adjusting alkalinity can be done by adding soda and may mean less coagulant is needed (cheaper)

86
Q

Water is densest at what temperature?

A

4 degrees

87
Q

Filtration removes up to __ percent of turbidity in water

A

95 percent

88
Q

Back washing methods

A

Surface wash

Air scour

89
Q

During filter ripening period, you perform what practice

A

Filter-waste

90
Q

Examine filter media condition includes checking for

A

Algae, mud balls, proper gradation

91
Q

What is gac?

A

Adsorption

Granulated activated carbon

92
Q

Chemical oxidation using compounds like potassium permanganate assist with what?

A

Destruction of organica and the oxidation of inorganic compounds that cause taste and odour

93
Q

NTU

A

Nephelometric turbidity units

94
Q

Regulated turbidity limits

A

1 NTU

95
Q

Secondary disinfection must create a residual and therefore must be done with….

A

Chlorination

96
Q

Alum is used in winter months

True or false

A

True

97
Q

Reg 170 talks about when and how,

169 lists chemical standards

A

True

98
Q

128/04

A

Training and certification

99
Q

Well legislation

A

908

100
Q

Drinking water systems are regulated under

A

170/03

101
Q

True or false

Any indication water isn’t properly disinfected according to opddwo is considered an adverse effect

A

True

102
Q

Chlorine to ammonia ratio

A

4.5:1

103
Q

Monochloramine is a weak primary disinfectant, but provides the best residual

T of F

A

True

104
Q

The most effective for no chorine residual

A

Hypochlourous acid

105
Q

True or false

Sodium hypochlorite increases the pH of water as is corrosive

A

True

106
Q

The most important dbps

A

Thms

107
Q

Pump curves and values require what information to determine values?

A

Capacity
Total head
Power
Efficiency

ELC Drinking Water Operator Course SSFC (1 decks)

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