ELC mid-term Flashcards by Kristin Phasey

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

O. Reg 170/03

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A certified operator receives training and certification under what regulation?

O. Reg 128/04

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

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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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

True

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Failure to comply with regulations can lead to what consequences?

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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Threats to source water

4 vulnerable areas in the CWA

Surface water intake protection zone

Wellhead protection area

Highly vulnerable aquifer

Significant groundwater recharge area

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The minimum alarm standard for free chlorine residual

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

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

0.25 mg/L

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The minimum and maximum free chlorine residual in a distribution sample

Maximum alarm standard is N/A

Minimum is 0.05 mg/L

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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 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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What is the Purpose of the coagulation process?

the rapid dispersion of coagulation to destabilize particles

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Adverse results of drinking water tests

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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Components of a free chlorine residual

Hypochlorous acid

Hypochlorite ion

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The minimum treatment required for a groundwater source

2-log removal/inactivation of viruses

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

ozone

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What disinfectants can be used for secondary disinfection?

Chlorine Gas
sodium hypochlorite
calcium hypochlorite
chlorine dioxide
chloramination

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Define Turbidity

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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True Colour vs Apparent Colour

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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factors affecting disinfection process

Dosage
temperature
mixing
pH
contact time
concentration of microorganisms
type of chemical

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Some common sources for taste/odour

algae
dissolved gases
dichloramines
minerals/other compounds

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drawbacks encountered when flushing

low water pressure
discoloured water
no water

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define alkalinity

the buffers against sudden changes in pH.

Necessary during coagulation process

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

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

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

4 feet

1.2 m

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

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

the breakpoint in chlorination is what exactly?

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

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

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

The difference between clearwells, standpipes and elevated tanks?

Clearwells store treated water for continuous operation Standpipes and elevated tanks are used for both storage, and pressure

the MAX, MIN and NORMAL pressures in the distribution system

NORMAL 40-80 psi MIN 20 psi MAX 100 psi

3 Factors that reduce shelf life of Sodium Hypochlorite

Concentration light heat

Pressure is defined as

Force per unit area

What is head loss?

pressure loss due to friction

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

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

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

Thrust is:

The force of water when it changes to a direction

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

Disinfection Bi-Products (DBP)

True or False Colloids usually have a negative electrical charge

True Why they do not attract and settle out without coagulant

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

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

what are the operational guidelines for pH in drinking water?

6.5-8.5

The regulations/guidelines that define GUDI

O.Reg 170/03 contains a checklist to identify groundwater sources

Multi-Barrier Approach What are the 5 barriers?

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

The CT Concept

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

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

Chemically assisted filtration, followed by disinfection (or equivalent) 99 % (2-Log) inactivation of Cryptosporidium 99. 9 % (3-log) inactivation of Giardia 99. 99 % (4 log) inactivation of viruses

3 Reasons for Secondary Disinfection

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

What chemicals can be used for secondary disinfection?

Chlorine Chlorine Dioxide monochloramine (only)

True or False Disinfection efficiency increases with the pH

False Lower ph is more efficiently treated

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

Non-GUDI | GUDI, only with chemically assisted filtration

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

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

Major Steps in Conventional Surface Water Treatment Process

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

Single level Intake vs. Multi level intake

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

The purpose of Tube Settlers

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

Purpose of storage facilities

``` Pressure Reduce size of transmission mains Firefighting Industrial requirements Balance fluctuating demands ```

Purpose of elevated tanks

Maintain pressure | Eliminate need for continuous pumping

Standpipes are storage tanks located where?

On ground level Providing low pressure Taller than diameter

What is a surge tank?

Controls water hammer | Absorbs sudden a pressure to provide air brakes

Preventing ice damage in water storage tanks can be done how

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

Types of piping

``` Cast iron Asbestos-cement Plastic-PVC Steel Concrete Others- ```

How often are storage tanks cleaned and drained?

Inspected annually and cleaned every 3 years

Larger diameter pipes are usually made of

Concrete

3 types of plastic pipes

PVC Hdpe PB

Tapping machines

Used to drill or thread holes into a pipe surface "Wet tapping" Ensure cutter bit is fully withdrawn

The most accurate way to detect leaks in distribution system

Sound rods

Unidirectional flushing

Flow of water in a single direction

Frozen lines are thawed how?

Electrical thawing Hot water Thawing using a steam generator "Steam Jennie"

Types of corrosion

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

Chlorine Demand =

Dosage-residual

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.

Head loss increase in turbidity the filter run time

4 different zones of a sedimentation tank

inlet zone settling zone sludge zone outlet zone

What is the recommended concentration of flouride in drinking water?

0.5-0.8 mg/L

3 chemicals typically used for fluoridation

sodium flouride hydrofluosilicid acid sodium silicofluoride

Common Chemical used as a coagulant in water treatment

Alum Aluminum Sulphate Al2(SO4)3

psi x ____ = kPa | kPa / ____ = pis

6.895

1m head = how much kPa?

9.804 kPa

Friction loss depends upon what factors

``` velocity pipe diameter length degree of roughness fittings/valves ```

Pressure lost due to friction

headloss

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

Cavitation

2 types of shoring

Timber shoring | Hydraulic aluminum shoring

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

True

Indicator organisms are used for what

To determine whether or not pathogens are present in raw water

True or false E. coli is always an indication of fecal contamination

True

True or false Sodium hypochlorite lowers pH

False... It increases ph

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

Zebra mussels

Direct filtration is basically conventional treatment with no ____________

Clarification Non gudi

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

Coagulation

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

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

Water is densest at what temperature?

4 degrees

Filtration removes up to __ percent of turbidity in water

95 percent

Back washing methods

Surface wash Air scour

During filter ripening period, you perform what practice

Filter-waste

Examine filter media condition includes checking for

Algae, mud balls, proper gradation

What is gac?

Adsorption Granulated activated carbon

Chemical oxidation using compounds like potassium permanganate assist with what?

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

NTU

Nephelometric turbidity units

Regulated turbidity limits

1 NTU

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

Chlorination

Alum is used in winter months True or false

True

Reg 170 talks about when and how, 169 lists chemical standards

True

128/04

Training and certification

Well legislation

908

Drinking water systems are regulated under

170/03

True or false Any indication water isn't properly disinfected according to opddwo is considered an adverse effect

True

Chlorine to ammonia ratio

4.5:1

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

True

The most effective for no chorine residual

Hypochlourous acid

True or false Sodium hypochlorite increases the pH of water as is corrosive

True

The most important dbps

Thms

Pump curves and values require what information to determine values?

Capacity Total head Power Efficiency

ELC mid-term Flashcards

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