FDEP Water treatment C exam

Units that combine coagulation, Flocc, & sedimentation into a single basin are:

Solid contact units

Valves that operate 90 degrees open to shut are:

Eccentric and butterfly

Which of the following methods is best for determining the depth of water in a clearwell:

bubbler

Chlorine expands approximately how many times from liquid to gas?

450

According to the safe water drinking act, the basic definition of public water supply system is any water system that supplies water for human consumption that serves:

15 service connections or over 25 persons for over 60 days a year

Normally calcium and magnesium ions are expressed as ________ when dealing with softening.

CaCo3

The water in the I-95 elevated tank has a temperature of 15 degrees Celsius, the PH is 8.7, pressure gauge is reading 52psi, cl2 residual is 3.8mg/l how many feet is the water tank?

52ft

15ft

38ft

120ft

120ft = (2.31x52)

What is the logarithm of the reciprocal the the hydrogen ion activity?

Acidic solution

Ph

standard solution

molar solution

Ph

What is the detention time in minutes for a basin that is 15th in diameter and 12ft deep and treats a flow of .532 mgd?

48 min.

487 min

42.9 min

27.53 min

42.9 D = volume / flow

Name two reserve flow conditions that cause back-flow in a distribution system.

water hammer and air gap

vacuum breaker and back sihponage

back-pressure and backflow

back-pressure and back siphonage

back-pressure and back siphonage

The nephlometric method of measuring turbidity is based on:

scattering of light

transmission of light

absorption of light

passage of light

scattering of light

what is the definition of the nutrient poor portion of the lake.

eutrophic

ogliotrophic

mesatrophic

hypotrophic

ogliotrophic

what is the definition of the nutrient rich portion of the lake.

eutrophic

ogliotrophic

mesatrophic

hypotrophic

eutrophic

Alkalinity consist predominately in which of the following forms?

Bicarbonate, carbonate, and hydroxide

carbon dioxide and bicarbonate

carbonate and carbon dioxide

carbonate, carbon dioxide, and bicarbonate

Bicarbonate, carbonate, and hydroxide

The highest concentration of hypoclorous acid occurs at what Ph?

5

6

7

8

5

What is the most important test to indicate proper sedimentation?

Ph

turbidity

head loss

chlorine residual

turbidity

Which of these are the stages in correct order for an ion exchange softener?

backwash, brine,rinse,and service

service,brine, backwash, and rinse

service, backwash,brine, and rinse

brine, rinse,backwash, and service

brine, rinse,backwash, and service

The amount of water per foot of the draw-down is commonly refered to as:

specific capacity

safe yield

pumping level

static level

specific capacity

free available residual chlorine has the highest disinfection ability?

True

Sludge produced by a solids-contact clarification unit is recycled through the process to act as a coagulant aid?

True

Always add acid to water, never the reverse.

True

When Iron and copper are joined, iron will protect and copper will corrode

false

water containing very little hardness tends to be more aggressive?

false

Completely empty volumetric pipets by blowing out the small amount remaining in the tip

false

Never pipet chemical reagent solutions or unknown water samples by mouth

true

What is the cause of stratification in lakes and reservoirs ?

Formation of separate layers of temperature, plant , or animal life

Solids-contact process units combine the coagulation, flocculation, and sedimentation processes in a single basin.

True

sludge produced by a solid-contact clarification unit is recycled through the process to act as a coagulant aid.

True

Super-chlorination is followed by dechlorination as part of the treatment for tastes and odors.

true

Federal laws include sludge from a water treatment plant as an industrial waste and require proper handling and disposal.

true

How extensive should the treatment be for reclaimed water?

Depends on potential exposure to the public.

How can Iron, Manganese and Hydrogen Sulfide be controlled in a reservoir?

By preventing dissolved oxygen depletion

What is the best tool for managing watersheds?

Regulatory process

What is the purpose of coagulation and flocculation?

To remove particulate impurities, especially nonsettle-able solids and color

After a jar test is completed, what does a hazy settled water indicate?

Poor coagulation

How can an operator verify the effectiveness of the coagulant chemicals and dosages being applied at the flash mixer?

Jar tests

What happens to the settling rate (settling velocity) of particles in the water when the water temperature drops?

They decrease as the temperature drops

What is the major way which operators can control water treatment processes?

Adjusting chemicals and chemical feed rates

Which task should be performed immediately following dewatering of a sedimentation basin?

Grease and lubricate all gears, sprockets, and mechanical moving parts that have been submerged.

How are filter production(capacity) rates measured?

Filter production(capacity) are measured MGD (Million Gallons per Day)

Why is surface wash used buring backwashing?

To prevent mudballs

What do significant changes in source water turbidity levels, either increase or decreases, require?

Immediate verification of filtration process effectiveness.

Why should a filter be drained if it is going to be out of service for a prolonged period of time?

To avoid algal growth

What are the components of a chlorine residual?

Combined chlorine forms plus free chlorine

Where should the minimum chlorine residual be measured in the distribution system?

the most remote location in the system

How are ORP probes used in the disinfection process?

ORP (Oxidation-reduction potential) probes provide a direct measure of the disinfecting power of the disinfectant

Why are zinc and magnesium commonly used as sacrificial anodes in water tanks or for buried pipes?

They will corrode preferentially to Aluminum and iron

Why should samples for corrosive tests be taken only after post-chlorination?

Because disinfectant chemicals may react with corrosion-control chemicals to either increase or decrease corrosivity

Where are monitoring samples for "the lead and Copper Rule" collected?

At the consumer's tap

What is the secret to successful taste and odor control?

Prevent tastes and odors from ever developing

Taste and odor removal can be divided into which categories?

removal and destruction

Where is powdered activated carbon often applied?

At the flash mixer

Over which water quality indicator do operators have the greatest control?

Turbidity

Which chemical is one of the most dangerous of the common alkalies?

Caustic soda (sodium hydroxide) (NaOH)

What should an operator do first when a treatment process upset results in the failure to meet a specific drinking water quality standard?

Notify local health authorities

which piece of laboratory equipment is the most accurate way to measure a volume of liquid?

Pipet

which piece of laboratory equipment is used to titrate a chemical reagent?

Buret

Which style of thermometer will change the most rapidly when removed from the liquid sample?

Total immersion

what is the accepted method used to measure turbidity?

Nephelometric

The size of a water treatment plant as well as the number of specific types of processes it uses depends on which of the following factors?

1. Cost

2. Demand

3. fire protection

4. impurities

5. water quality standards

1,2,3,4,5

which of the following tasks are typical duties for a water treatment operator?

1.collect representative water samples

2.conduct safety inspections

3.maintain plant records

4.make periodic operating checks of plant equipment

5.preform routine maintenance

1,2,3,4,5

What is the probable cause of a drop chlorine level?

increase in chlorine demand

What are the two forms of activated carbon used in water treatment?

PAC & GAC

Following the softening process, the pH is high and the water is _____ with excess caustic alkalinity in either the hydroxide or carbonate form.

Supersaturated

What is split treatment mainly used for?

Remove Magnesium

What is a hypochlorinator ?

Chlorine pumps, chemical feed pumps, or devices used to dispense chlorine solutions made from hypochlorites, such as bleach (sodium hypochlorite) or calcium hypochlorite, into the water being treated.

WHAT ARE TWO METHODS OF FEEDING HYPOCHLORITE?

Eject/inject and direct

which of the following are commonly used coagulation chemicals?

Alum

Hypochlorites

metallic salts

polymers

sodium chlorida

Alum, metallic salts, polymers

Which of the following factors are important when evaluating jar test?

1) The amount of floc formed

2) Clarity of the water above settled floc

3)Clarity of water between floc particles

4)Floc settling rate

5) Sodium chloride

all of the above

Which items are adjusted in the enhanced coagulation process?

1) basic contents

2)coagulation dosage

3)detention time

4)mixing

5)pH

coagulation dosage, pH

Why is short-circuiting undesirable in a sedimentation basin?

Shorter contact times, shorter reaction times, shorter settling times

What kind of changes cause instability in solid-contact units?

coliforms, temperature, turbidity

which water quality indicators should be monitored in the normal operation of the sedimentation process?

temperature, turbidity

How can an operator determine if a filter is not completely clean after backwashing?

initial head loss is too high, next filter run is too low

What precautions should be taken when handling powdered activate carbon(PAC)?

1) follow confined space safety precautions

2) store PAC bags on wooden pallets

3) store PAC away from flammable materials

4) use dust control equipment

5) wear protective clothing

1,2,3,4,5

An alkalinity determination is needed when calculating chemical doses used in what water treatment processes?

1) coagulation

2) filtration

3) flocculation

4) settling

5) softening

1,5

grab sampler

a single sample of water collected at a particular time and place which represents the composition of the water only at a time and place

Short-circuiting

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.

what is the difference between the coagulation and the flocculation processes?

In the coagulation process , chemicals are added to the water being treated that will cause suspended particles to clump together. The chemicals are mixed by a flash or rapid mixer. In the flocculation process, particles gather together to form large by gently stirring or mixing

List the four zones into which a typical sedimentation basin can be divided.

inlet, settling, sludge, outlet

Hard water contains an abundance of

a. sodium

b. iron

c. lead

d. calcium carbonate

calcium carbonate

Groundwaters generally have consistent water quality that include

a. having a higher total dissolved solids content than surface water

b. having a lower mineral content than surface waters

c. having lower pH values than surface waters

d. having a higher amount of bacteria than surface waters

having a higher total dissolved solids content than surface wate

Baffling inside a storage facility may be needed to prevent "hot spots" and

a. straight through flows

b. long contact times with disinfectants

c. high chlorine residuals throughout the facility

d. high temperatures throughout the storage facility

straight through flows

A commonly used method to test for chlorine residual in water is called the _____ method.

a. HTH

b. THM

c. VOC

d. DPD

DPD

When chlorine gas is added to water the pH goes down due to

two acids that form:

hypochlorous acid and hydrochloric acid

Water with a pH of 8.0 is considered to be

basic or alkaline

Which of the following are commonly used coagulation chemicals?

alum and polymers

How can an operator tell if a filter is NOT completely cleaned after backwashing

the initial headloss is on the high side

A high level of ______ in the water can cause the "blue-baby" syndrome

Nitrates

The filtration unit process usually

follows the coagulation/flocculation/sedimentation processes

Filters are generally backwashed when the loss-of-head indicator registers a certain set value, such as 6-ft, or upon a certain time, say 48-hours, or upon a rise in

turbidity

Water hardness is the measure of the concentrations of __________ and __________ dissolved in the water sample.

calcium & magnesium carbonates

Primary drinking water standards are set to protect the public from illnesses as a direct result in drinking water that exceeds maximum set levels. Secondary standards were set to alert the public to

aesthetic issues with drinking water

When underground water is under pressure greater than atmospheric pressure and could rise above the its confining space and above the ground level is referred to as a

artesian effect

The water right to put it to beneficial use of the surface water adjacent to your land is called ____________ water.

riparian

The electrical potential required to transfer electrons from one compound or element to another is commonly referred to as

oxidation-reduction potential (ORP)

pH is decreased by the removal of carbon dioxide

true

what color is chlorine gas?

yellow

what is formed when chlorine reacts with ammonia?

chlorimines

Calcium hypochlorite (Ca(OCl)2)

granular Chlorine , Available Chlorine 40-78%