Water Treatment Processes and Ozone Treatment of the

Source

Water Treatment Processes and Ozone Treatment of the

Source

WQT 131Water Works Operation III

Water Treatment

Chapter 1 Water Treatment ProcessesChapter 2 Treatment of Water at the Source

OZONE

Lecture 1

WQT 131Water Works Operation III

Water Treatment

Chapter 1 Water Treatment ProcessesChapter 2 Treatment of Water at the Source

OZONE

Lecture 1

Week 1 Objectives Week 1 Objectives

1. Understand common water treatment processes

2. Understand ways to control biological growth and maintain clean water at the source

3. OZONE

1. Understand common water treatment processes

2. Understand ways to control biological growth and maintain clean water at the source

3. OZONE

Reading assignment: AWWA 2003. Water Treatment, Principles and Practices of Water Supply Operation, Third Edition, American Waterworks Association, ISBN 1-58321-230-2

Chapter 1 Water Treatment ProcessesChapter 2 Treatment of Water at the SourceChapter 7 Disinfection and OZONE FACT SHEET

Reading assignment: AWWA 2003. Water Treatment, Principles and Practices of Water Supply Operation, Third Edition, American Waterworks Association, ISBN 1-58321-230-2

Chapter 1 Water Treatment ProcessesChapter 2 Treatment of Water at the SourceChapter 7 Disinfection and OZONE FACT SHEET

Key WordsKey Words• Disinfectants: kill unwanted microorganisms in water.

• Algaecides: chemicals that kill blue or green algae, when added to water.

• Coagulants: used to remove clay, organic matter, small suspended particles, iron, and manganese from water

• Surface Water Systems: Treatment and use of surface water to supply industries and domestic residences.

• Groundwater Systems: Groundwater extracted for the sole purpose of supply.

• Disinfectants: kill unwanted microorganisms in water.

• Algaecides: chemicals that kill blue or green algae, when added to water.

• Coagulants: used to remove clay, organic matter, small suspended particles, iron, and manganese from water

• Surface Water Systems: Treatment and use of surface water to supply industries and domestic residences.

• Groundwater Systems: Groundwater extracted for the sole purpose of supply.

The destruction of the larger portion of microorganisms with

the probability that all pathogens are killed is called ?

The destruction of the larger portion of microorganisms with

the probability that all pathogens are killed is called ?

Dig

estio

n

Dis

infe

ctio

n

Dilu

tion

Ste

riliz

atio

n

Dis

posal

20% 20% 20%20%20%

1. Digestion

2. Disinfection

3. Dilution

4. Sterilization

5. Disposal

1. Digestion

2. Disinfection

3. Dilution

4. Sterilization

5. Disposal

CH 1 Water Treatment Processes

CH 1 Water Treatment Processes

WQT 131Water Works Operation III

Water Treatment

Chapter 1 Water Treatment Processes

WQT 131Water Works Operation III

Water Treatment

Chapter 1 Water Treatment Processes

Surface Water SystemsSurface Water Systems• Surface water sources are open to contamination from human and animal waste and other pollution.

•Must comply with the Federal Surface Water Treatment Rule (SWTR) and include filtration, disinfection, operating, monitoring, and reporting requirements.

•Water is always treated prior to distribution

•Treatment for microorganisms, low turbidity, and must have a minimum disinfectant residual.

• Surface water sources are open to contamination from human and animal waste and other pollution.

•Must comply with the Federal Surface Water Treatment Rule (SWTR) and include filtration, disinfection, operating, monitoring, and reporting requirements.

•Water is always treated prior to distribution

•Treatment for microorganisms, low turbidity, and must have a minimum disinfectant residual.

Source waters include these two broad categories

Source waters include these two broad categories

25% 25%25%25%a. Surface water and ground water

b. Reservoirs and wells

c. Reservoirs and ground water

d. Flowing water and stagnant water

a. Surface water and ground water

b. Reservoirs and wells

c. Reservoirs and ground water

d. Flowing water and stagnant water

The formation of layers of different temperature in a

body of water is called what?

The formation of layers of different temperature in a

body of water is called what?

Ther

mal

stra

tific

atio

n

Ther

mal

just

ifica

tion

Lim

noptic

laye

ring

Lim

noptic

stra

tific

atio

n

25% 25%25%25%1. Thermal stratification

2. Thermal justification

3. Limnoptic layering

4. Limnoptic stratification

1. Thermal stratification

2. Thermal justification

3. Limnoptic layering

4. Limnoptic stratification

Groundwater in comparison to surface water is generally:

Groundwater in comparison to surface water is generally:

20% 20% 20%20%20%1. Lower in turbidity and higher in mineral content

2. Higher in turbidity and lower in mineral content

3. More susceptible to seasonal changes

4. More susceptible to algal blooms

5. Warmer and is quite soft

1. Lower in turbidity and higher in mineral content

2. Higher in turbidity and lower in mineral content

3. More susceptible to seasonal changes

4. More susceptible to algal blooms

5. Warmer and is quite soft

Water Treatment StepsWater Treatment Steps

1. Pretreatment – At the Source

2. Coagulation and Flocculation

3. Sedimentation

4. Filtration-Sand filters or Ultra Filtration Membranes

5. Disinfection-chlorine, Ozone, UV

6. Corrosion control- caustic soda or lye NaOHSoda ash Na2CO3 Sodium bicarbonate (baking soda) NaHCO3

1. Pretreatment – At the Source

2. Coagulation and Flocculation

3. Sedimentation

4. Filtration-Sand filters or Ultra Filtration Membranes

5. Disinfection-chlorine, Ozone, UV

6. Corrosion control- caustic soda or lye NaOHSoda ash Na2CO3 Sodium bicarbonate (baking soda) NaHCO3

Conventional Treatment Conventional Treatment • Conventional Treatment – Common treatment steps used to remove turbidity from the initial source water.

• Conventional Treatment – Common treatment steps used to remove turbidity from the initial source water.

2. Flocculation2. Flocculation 3. Sedimentation3. Sedimentation 4. Filtration4. Filtration1. Coagulation1. Coagulation

PretreatmentPretreatment

Raw WaterRaw Water

Rapid or flash Mixing

Alum, polymer

Rapid or flash Mixing

Alum, polymer

SlowSlowFastFast

SludgeSludgeWashwaterWashwater

5. Clear Well Disinfection5. Clear Well Disinfection

Distri

bution

Distri

bution

ClearwellBackwash

pumps

ClearwellBackwash

pumps

ChlorinationOzone

UV

ChlorinationOzone

UVAlkalinity

adjustmentAlkalinity

adjustment

The correct order of treatment in a surface water plant is:

The correct order of treatment in a surface water plant is:

a. f

iltra

tion, d

isin

fect

i...

b. s

edim

enta

tion,

floc.

..

c. c

oagula

tion, f

locc

ul...

d. f

locc

ulatio

n, coag

u...

25% 25%25%25%a. filtration, disinfection, softening, and coagulation

b. sedimentation, flocculation, softening, and coagulation

c. coagulation, flocculation, sedimentation, and filtration

d. flocculation, coagulation, filtration, and sedimentation

a. filtration, disinfection, softening, and coagulation

b. sedimentation, flocculation, softening, and coagulation

c. coagulation, flocculation, sedimentation, and filtration

d. flocculation, coagulation, filtration, and sedimentation

Agglomeration of colloidal and finely divided suspended matter

after coagulation by gentle mixing is called what?

Agglomeration of colloidal and finely divided suspended matter

after coagulation by gentle mixing is called what?

Flo

ccula

tion

Sed

imen

tatio

n

Poly

mer

acc

retio

n

Bal

last

ing

25% 25%25%25%1. Flocculation

2. Sedimentation

3. Polymer accretion

4. Ballasting

1. Flocculation

2. Sedimentation

3. Polymer accretion

4. Ballasting

Under normal conditions, coagulation:

Under normal conditions, coagulation:

Occ

urs

in s

econds

Occ

urs

in m

inute

s

Occ

urs

in h

ours

None

of the

abo

ve

25% 25%25%25%1. Occurs in seconds

2. Occurs in minutes

3. Occurs in hours

4. None of the above

1. Occurs in seconds

2. Occurs in minutes

3. Occurs in hours

4. None of the above

The main purpose of coagulation/flocculation is to:

The main purpose of coagulation/flocculation is to:

Rem

ove tu

rbid

ity

Softe

n wat

er

Add o

xygen

to w

ater

Dis

infe

ct w

ater

25% 25%25%25%1. Remove turbidity

2. Soften water

3. Add oxygen to water

4. Disinfect water

1. Remove turbidity

2. Soften water

3. Add oxygen to water

4. Disinfect water

The main purpose of pre-sedimentation is to:

The main purpose of pre-sedimentation is to:

Incr

ease

the

oxyge

n ...

Incr

ease

alk

alin

ity in

...

Red

uce

the

oxygen

c...

Red

uce

the

silt

in th

e...

25% 25%25%25%1. Increase the oxygen content of water

2. Increase alkalinity in the water

3. Reduce the oxygen content in the water

4. Reduce the silt in the water

1. Increase the oxygen content of water

2. Increase alkalinity in the water

3. Reduce the oxygen content in the water

4. Reduce the silt in the water

Sedimentation is a process that _________ suspended matter.: Sedimentation is a process that _________ suspended matter.:

Set

tles

Coag

ulate

s

Flo

ccula

tes

Filt

ers

25% 25%25%25%

1. Settles

2. Coagulates

3. Flocculates

4. Filters

1. Settles

2. Coagulates

3. Flocculates

4. Filters

Sedimentation is improved by: Sedimentation is improved by:

Short

circ

uiting

Red

ucin

g the

deten

ti..

Unifo

rm, h

orizont

al, .

..

A s

ludg

e bla

nket t

hat...

25% 25%25%25%

1. Short circuiting

2. Reducing the detention period

3. Uniform, horizontal, low-velocity flow across the basin

4. A sludge blanket that acts as a physical filter for incoming solids

1. Short circuiting

2. Reducing the detention period

3. Uniform, horizontal, low-velocity flow across the basin

4. A sludge blanket that acts as a physical filter for incoming solids

The normal range of detention times used in sedimentation basins in conventional water

treatment plants is about:

The normal range of detention times used in sedimentation basins in conventional water

treatment plants is about:

A d

ay

60

sec.

10

sec.

3-6

hou

rs

25% 25%25%25%1. A day

2. 60 sec.

3. 10 sec.

4. 3-6 hours

1. A day

2. 60 sec.

3. 10 sec.

4. 3-6 hours

In conventional water treatment practices, the final step in the

removal of suspended matter is:

In conventional water treatment practices, the final step in the

removal of suspended matter is:

Chlo

rinat

ion

Flo

ccula

tion

Circ

ulat

ion

Filt

ratio

n

25% 25%25%25%1. Chlorination

2. Flocculation

3. Circulation

4. Filtration

1. Chlorination

2. Flocculation

3. Circulation

4. Filtration

• Chemical Precipitation:

Chemical precipitation= coagulation, flocculation, oxidation. Various salts of aluminum (e.g., alum), iron, manganese, lime and other inorganic or organic chemicals are widely used processes to treat water for the removal of colloidal particles (turbidity) and microbes.

• Chemical Precipitation:

Chemical precipitation= coagulation, flocculation, oxidation. Various salts of aluminum (e.g., alum), iron, manganese, lime and other inorganic or organic chemicals are widely used processes to treat water for the removal of colloidal particles (turbidity) and microbes.

Water Treatment Water Treatment

• Coagulation: Clarification methods that work by using chemicals which effectively "glue" small suspended particles together, so that they settle out of the water or stick to sand or other granules in a granular media filter. Coagulation works by eliminating the natural electrical charge of the suspended particles so they attract and stick to each other. The joining of the particles so that they will form larger settleable particles is called flocculation. (http://en.wikipedia.org/wiki/Water_purification).

• Coagulation: Clarification methods that work by using chemicals which effectively "glue" small suspended particles together, so that they settle out of the water or stick to sand or other granules in a granular media filter. Coagulation works by eliminating the natural electrical charge of the suspended particles so they attract and stick to each other. The joining of the particles so that they will form larger settleable particles is called flocculation. (http://en.wikipedia.org/wiki/Water_purification).

Water Treatment Water Treatment

Which one of the following chemicals would you most likely

use as a coagulant?:

Which one of the following chemicals would you most likely

use as a coagulant?:

Cat

ionic

pol

ymer

Sulfu

ric a

cid

Hyd

roch

loric

aci

d

Sodiu

m h

ydro

xide

25% 25%25%25%1. Cationic polymer

2. Sulfuric acid

3. Hydrochloric acid

4. Sodium hydroxide

1. Cationic polymer

2. Sulfuric acid

3. Hydrochloric acid

4. Sodium hydroxide

Which is the best method to remove sand from water?

Which is the best method to remove sand from water?

Add li

me

Aer

ate

Pro

vide

a se

ttlin

g tank

Use

zeolit

e so

ftenin

g

25% 25%25%25%1. Add lime

2. Aerate

3. Provide a settling tank

4. Use zeolite softening

1. Add lime

2. Aerate

3. Provide a settling tank

4. Use zeolite softening

Lamella Tubular SettlersLamella Tubular Settlers

Tube settlers are used to:Tube settlers are used to:

Aid

coa

gulatio

n

Impro

ve tu

rbid

ity re

...

Red

uce

flow

sta

bility

Rem

ove h

ardne

ss

25% 25%25%25%1. Aid coagulation

2. Improve turbidity removal

3. Reduce flow stability

4. Remove hardness

1. Aid coagulation

2. Improve turbidity removal

3. Reduce flow stability

4. Remove hardness

What conditions call for the use of plate or tube settlers?:

What conditions call for the use of plate or tube settlers?:

Ext

rem

ely

turb

id w

ater

Hig

h iron a

nd m

anga

...

Zeb

ra m

usse

l infe

stat

ion

Alg

al b

loom

25% 25%25%25%1. Extremely turbid water

2. High iron and manganese

3. Zebra mussel infestation

4. Algal bloom

1. Extremely turbid water

2. High iron and manganese

3. Zebra mussel infestation

4. Algal bloom

• Air Stripping: Air stripping is a full-scale technology in which volatile organics are partitioned from ground water by greatly increasing the surface area of the contaminated water exposed to air. (http://www.frtr.gov/matrix2/section4/4_50.html).

• Air Stripping: Air stripping is a full-scale technology in which volatile organics are partitioned from ground water by greatly increasing the surface area of the contaminated water exposed to air. (http://www.frtr.gov/matrix2/section4/4_50.html).

Water Treatment Water Treatment

Water Treatment Water Treatment

• Ion exchange: Ion exchange is a reversible chemical reaction wherein an ion (an atom or molecule that has lost or gained an electron and thus acquired an electrical charge) from solution is exchanged for a similarly charged ion attached to an immobile solid particle (http://www.remco.com/ix.htm).

• Ion exchange: Ion exchange is a reversible chemical reaction wherein an ion (an atom or molecule that has lost or gained an electron and thus acquired an electrical charge) from solution is exchanged for a similarly charged ion attached to an immobile solid particle (http://www.remco.com/ix.htm).

Water Treatment Water Treatment

• Ultrafiltration (UF) Membrane Processes: Membrane filtration in which hydrostatic pressure forces a liquid against a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane (http://en.wikipedia.org/wiki/Ultrafiltration).

• Ultrafiltration (UF) Membrane Processes: Membrane filtration in which hydrostatic pressure forces a liquid against a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane (http://en.wikipedia.org/wiki/Ultrafiltration).

CH 2 Treatment of Water at the Source

CH 2 Treatment of Water at the Source

WQT 131Water Works Operation III

Water Treatment

Chapter 2 Treatment of Water at the Source

WQT 131Water Works Operation III

Water Treatment

Chapter 2 Treatment of Water at the Source

Aquatic PlantsAquatic Plants

Algae: encompass several groups of relatively simple, eukaryotic, living aquatic organisms that capture light energy through photosynthesis, using it to convert inorganic substances into organic substances. ~17,500 species Blue green, green, diatoms, and pigmented flagellates

Algae: encompass several groups of relatively simple, eukaryotic, living aquatic organisms that capture light energy through photosynthesis, using it to convert inorganic substances into organic substances. ~17,500 species Blue green, green, diatoms, and pigmented flagellates

Aquatic PlantsAquatic PlantsEmergent Plant: shallow water near shoreline (cattails)

Floating Plant: have leaves floating on surface (Water lilies)

Submereged Plant: completely underwater (Coontail)

Emergent Plant: shallow water near shoreline (cattails)

Floating Plant: have leaves floating on surface (Water lilies)

Submereged Plant: completely underwater (Coontail)

Algae ProblemsAlgae Problems

•Taste, Odor, Color-metabolic by products •Toxicity-some species toxic•Filter Clogging-blind the filter•Slime Accumulation:algae=light; bacteria=dark•Corrosion-alter pH•Interference-alter pH, alkalinity, DO, OM•THM-react with Cl2 produce THM

•Taste, Odor, Color-metabolic by products •Toxicity-some species toxic•Filter Clogging-blind the filter•Slime Accumulation:algae=light; bacteria=dark•Corrosion-alter pH•Interference-alter pH, alkalinity, DO, OM•THM-react with Cl2 produce THM

Aquatic Plants ControlAquatic Plants Control

Physical (removal)-harvesting, digging, dewatering, dredging, shading, lining.

Biological-crayfish, snails, fish

Chemical-algaecides, herbicides

Physical (removal)-harvesting, digging, dewatering, dredging, shading, lining.

Biological-crayfish, snails, fish

Chemical-algaecides, herbicides

AlgaecidesAlgaecidesEx: Copper sulfate, iron salts, rosin amine salts and benzalkonium chloride

Algaecides are effective against algae, but are not very usable for algal blooms. Kill all present algae, but they do not remove the toxins that are released by the algae prior to death.

Ex: Copper sulfate, iron salts, rosin amine salts and benzalkonium chloride

Algaecides are effective against algae, but are not very usable for algal blooms. Kill all present algae, but they do not remove the toxins that are released by the algae prior to death.

Copper SulfateCopper Sulfate

Copper sulfate application

•*pH, *Alkalinity, Temp, Suspended Solids, Organic Content

•1.3 mg/L EPA DWS at the tap

•Not all algae killed by CUSO4

•Ideal: pH 8-9 and CaCO3 50 mg/L

•Safe dosage to fish: 0.5 mg/L, Trout Sensitive at 0.14 mg/L

•Pesticide regulated by EPA under Federal Insecticide, Fungicide, and Rodenticide act (FIFRA)

Copper sulfate application

•*pH, *Alkalinity, Temp, Suspended Solids, Organic Content

•1.3 mg/L EPA DWS at the tap

•Not all algae killed by CUSO4

•Ideal: pH 8-9 and CaCO3 50 mg/L

•Safe dosage to fish: 0.5 mg/L, Trout Sensitive at 0.14 mg/L

•Pesticide regulated by EPA under Federal Insecticide, Fungicide, and Rodenticide act (FIFRA)

Copper SulfateCopper Sulfate

Copper sulfate application

•Turns water greyish white, apply every 10-14 days•Tow bag or spray

Copper sulfate application

•Turns water greyish white, apply every 10-14 days•Tow bag or spray

Copper sulfate is used primarily to:

Copper sulfate is used primarily to:

des

troy

algae

pre

cipi

tate

cal

cium

c...

hel

p pr

even

t cor

rosi

on

lower

pH

25% 25%25%25%1. destroy algae

2. precipitate calcium carbonate

3. help prevent corrosion

4. lower pH

1. destroy algae

2. precipitate calcium carbonate

3. help prevent corrosion

4. lower pH

Potassium PermanganatePotassium Permanganate

Potassium Permanganate application

•Oxidizes iron which is needed for photosynthesis=plants die

•Tow bag or spray

•Strong Oxidizer

Potassium Permanganate application

•Oxidizes iron which is needed for photosynthesis=plants die

•Tow bag or spray

•Strong Oxidizer

In water treatment, potassium permanganate is used

primarily as:

In water treatment, potassium permanganate is used

primarily as:

An o

xidan

t

A d

isin

fect

ant

A tr

acin

g Age

nt

A c

orros

ion in

hibito

r

A c

oagul

ant

20% 20% 20%20%20%1. An oxidant

2. A disinfectant

3. A tracing Agent

4. A corrosion inhibitor

5. A coagulant

1. An oxidant

2. A disinfectant

3. A tracing Agent

4. A corrosion inhibitor

5. A coagulant

Powdered Activated CarbonPowdered Activated Carbon

Powdered Activated Carbon •Block sunlight thus no photosynthesis=plants die

Pond Covers

•Block sunlight

Powdered Activated Carbon •Block sunlight thus no photosynthesis=plants die

Pond Covers

•Block sunlight

CH 7 Disinfection OzoneCH 7 Disinfection Ozone

WQT 131Water Works Operation III

Water Treatment

Chapter 7 Disinfection OzoneOZONE FACT SHEET

WQT 131Water Works Operation III

Water Treatment

Chapter 7 Disinfection OzoneOZONE FACT SHEET

Water Treatment DisinfectantsWater Treatment Disinfectants Ozone Ozone

Ozone (O3)Ozone (O3)Factoids• Colorless gas (thunderstorm smell)• Greenhouse gas• Highly unstable• STRONGEST OXIDANT!!• Corrosive!

Factoids• Colorless gas (thunderstorm smell)• Greenhouse gas• Highly unstable• STRONGEST OXIDANT!!• Corrosive!

Ozone (O3)Ozone (O3)Water Industry• Discovered in 1783 Van Marcum• First Ozonator = 1857• Commercial Ozonator =1893• Widely used in Europe (France)• Start with air, oxygen, or even liquid oxygen

Water Industry• Discovered in 1783 Van Marcum• First Ozonator = 1857• Commercial Ozonator =1893• Widely used in Europe (France)• Start with air, oxygen, or even liquid oxygen

Ozone (O3)Ozone (O3)How is it produced?How is it produced?

•Start with air, oxygen, or even liquid oxygen

•The higher the purity of air/oxygen the better the quality of ozone!

•Low moisture and dry air

•Bubbled into a ozone contactor

•Start with air, oxygen, or even liquid oxygen

•The higher the purity of air/oxygen the better the quality of ozone!

•Low moisture and dry air

•Bubbled into a ozone contactor

Ozone (O3)Ozone (O3)How is it produced?How is it produced?

Liquid oxygen goes to oxygen gasLiquid oxygen goes to oxygen gas

oxygen gas gets ruptured by high volt arc into free oxygen radical which combines with oxygen gas to form ozone

oxygen gas gets ruptured by high volt arc into free oxygen radical which combines with oxygen gas to form ozone

Ozone (O3)Ozone (O3)How does it work?• Kills by oxidation

• reacts with components of cell wall: phospholipids

• Causes cell leakage and lysis of glycoprotein

• Breaks H bonds in DNA

How does it work?• Kills by oxidation

• reacts with components of cell wall: phospholipids

• Causes cell leakage and lysis of glycoprotein

• Breaks H bonds in DNA

Ozone ProductionOzone Production• Corona-discharge method is used at WRWTP. A 15,000 volt

arc ruptures the O2 into two free oxygen radicals.

• The oxygen atoms want to be stable so the atoms recombine into a combination of oxygen gas (90%) and ozone or O3 (10%).

• Ozone production is very energy intensive and creates a lot of heat.

• Calcium thiosulfate is added as a catalyst to decrease the half life of the ozone (to deozonate or remove it).

• Corona-discharge method is used at WRWTP. A 15,000 volt arc ruptures the O2 into two free oxygen radicals.

• The oxygen atoms want to be stable so the atoms recombine into a combination of oxygen gas (90%) and ozone or O3 (10%).

• Ozone production is very energy intensive and creates a lot of heat.

• Calcium thiosulfate is added as a catalyst to decrease the half life of the ozone (to deozonate or remove it).

Ozone (O3)Ozone (O3)Advantages

• No chemicals• No taste, color, or odor problems• Takes care of algae, organics, Fe, and Mn in water• No toxic residual!• Increases dissolved oxygen levels• No ammonia demand at pH > 9• Instantaneous disinfection= low contact time• No DBP or THM• Effective disinfection over wide range of pH and Temp

Advantages

• No chemicals• No taste, color, or odor problems• Takes care of algae, organics, Fe, and Mn in water• No toxic residual!• Increases dissolved oxygen levels• No ammonia demand at pH > 9• Instantaneous disinfection= low contact time• No DBP or THM• Effective disinfection over wide range of pH and Temp

Ozone (O3)Ozone (O3)

• Higher initial capitol cost then chlorine or UV!• Ozone exposure=serious hazard (0.1 mg/L work area)• On site generation• Some ozone byproducts (aldehydes and ketones)• Can react with bromide • No residual so you still need chlorine• Short half life• Corrosive (need calcium thiosulfate)• Equipment malfunctions• Lots of electricity• Short lived/no residual still may need chlorine

• Higher initial capitol cost then chlorine or UV!• Ozone exposure=serious hazard (0.1 mg/L work area)• On site generation• Some ozone byproducts (aldehydes and ketones)• Can react with bromide • No residual so you still need chlorine• Short half life• Corrosive (need calcium thiosulfate)• Equipment malfunctions• Lots of electricity• Short lived/no residual still may need chlorine

DisadvantagesDisadvantages

Tonight's Lecture Objectives: To understand basic water

treatment processes and using ozone for disinfection has been

met?

Tonight's Lecture Objectives: To understand basic water

treatment processes and using ozone for disinfection has been

met?

Stro

ngly Agree

Agree

Neutra

l

Disa

gree

Stro

ngly Disa

gree

78%

22%

0%0%0%

1. Strongly Agree

2. Agree

3. Neutral

4. Disagree

5. Strongly Disagree

1. Strongly Agree

2. Agree

3. Neutral

4. Disagree

5. Strongly Disagree