chlorination in waterworks operation waterworks operations i wqt 111 chlorination
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Chlorination in Waterworks Operation
Chlorination in Waterworks Operation
Waterworks Operations IWQT 111
Chlorination
Waterworks Operations IWQT 111
Chlorination
http://www.c3.org/chlorine_knowledge_center/history.html
http://www.wrb.state.ri.us/programs/eo/historydrinkingwater.htm
http://ewr.cee.vt.edu/environmental/teach/wtprimer/chlorine/chlorine.html
Week Objectives Week Objectives
1. Comprehend “the basics” of chlorine chemistry
2. Understand the advantages and disadvantages of chlorine
3. Understand the history of chlorine via a timeline
4. Understand Breakpoint Chlorination Curve
5. Calculate C•T values
1. Comprehend “the basics” of chlorine chemistry
2. Understand the advantages and disadvantages of chlorine
3. Understand the history of chlorine via a timeline
4. Understand Breakpoint Chlorination Curve
5. Calculate C•T values
Reading assignment: Water Treatment , Chapter 7: DisinfectionReading assignment: Water Treatment , Chapter 7: Disinfection
Key WordsKey WordsChlorine Residual- Measurable chlorine remaining after the
demand is satisfied.
Chlorine Demand- The amount of chlorine destroyed by reaction with Fe, Mn, turbidity, organics, and microorganisms in the water.
Free Chlorine Residual- point past breakpoint where
HOCl (hypochlorous acid) and OCL- (hypochlorite ion) form.
25 times more powerful than combined chlorine for disinfection
Combined residual chlorine: chlorine combined with organics or ammonia.
• NH2Cl (monochloramine) and
• NH(Cl)2 (dichloramine)
• N(Cl)3 (nitrogen trichloride)
Chlorine Residual- Measurable chlorine remaining after the demand is satisfied.
Chlorine Demand- The amount of chlorine destroyed by reaction with Fe, Mn, turbidity, organics, and microorganisms in the water.
Free Chlorine Residual- point past breakpoint where
HOCl (hypochlorous acid) and OCL- (hypochlorite ion) form.
25 times more powerful than combined chlorine for disinfection
Combined residual chlorine: chlorine combined with organics or ammonia.
• NH2Cl (monochloramine) and
• NH(Cl)2 (dichloramine)
• N(Cl)3 (nitrogen trichloride)
Key WordsKey WordsBreakpoint chlorination: The point at which near complete
oxidation of nitrogen compounds are reached . Any point beyond breakpoint is mostly free chlorine (HOCL and OCL-)
C•T (concentration and contact time): Effectiveness of chlorination is dependant on chlorine concentration and contact time.
Sterilization: The destruction of all living things in a sample
Disinfection: The removal or inactivation of disease causing (pathogenic) organisms
Chlorine Demand= Chlorine Dose- Chlorine Residual
Breakpoint chlorination: The point at which near complete oxidation of nitrogen compounds are reached . Any point beyond breakpoint is mostly free chlorine (HOCL and OCL-)
C•T (concentration and contact time): Effectiveness of chlorination is dependant on chlorine concentration and contact time.
Sterilization: The destruction of all living things in a sample
Disinfection: The removal or inactivation of disease causing (pathogenic) organisms
Chlorine Demand= Chlorine Dose- Chlorine Residual
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
0%
79%
0%
21%
0%
1. Digestion
2. Disinfection
3. Dilution
4. Sterilization
5. Disposal
1. Digestion
2. Disinfection
3. Dilution
4. Sterilization
5. Disposal
Proper disinfection kills all organisms?
Proper disinfection kills all organisms?
Tru
e
Fal
se
91%
9%
1. True
2. False
1. True
2. False
Chlorine applied minus ____ equals chlorine residual
Chlorine applied minus ____ equals chlorine residual
Chlo
rine
dose
Chlo
rine
dem
an...
Com
bined
chlo
r...
Fre
e ch
lorin
e
Tota
l chlo
rine
6%
88%
6%0%0%
1. Chlorine dose
2. Chlorine demand
3. Combined chlorine
4. Free chlorine
5. Total chlorine
1. Chlorine dose
2. Chlorine demand
3. Combined chlorine
4. Free chlorine
5. Total chlorine
CL2 Demand= Cl2 Dose- Cl2 Residual?CL2 Demand= Cl2 Dose- Cl2 Residual?
Tru
e
Fal
se
7%
93%
1. True
2. False
1. True
2. False
A low chlorine dose w/ longer the contact time can have the same
disinfecting power as a high chlorine dose with a short detention time?
A low chlorine dose w/ longer the contact time can have the same
disinfecting power as a high chlorine dose with a short detention time?
Tru
e
Fal
se
0%
100%
1. True
2. False
1. True
2. False
The amount of chlorine destroyed by reaction with Fe, Mn, turbidity,
organics, and microorganisms in the water?
The amount of chlorine destroyed by reaction with Fe, Mn, turbidity,
organics, and microorganisms in the water?
Fre
e Chlo
rine
Resid
ual
Chlo
rine
Deman
d
Chlo
rine
Resid
ual
11% 6%
83%1. Free Chlorine Residual
2. Chlorine Demand
3. Chlorine Residual
1. Free Chlorine Residual
2. Chlorine Demand
3. Chlorine Residual
Measurable chlorine remaining after the demand is
satisfied.
Measurable chlorine remaining after the demand is
satisfied.
Chlo
rine
Deman
d
Chlo
rine
Resid
ual
100%
0%
1. Chlorine Demand
2. Chlorine Residual
1. Chlorine Demand
2. Chlorine Residual
HOCL?HOCL?
Hyp
ochlo
rous
acid
Hyp
ochlo
rite
ion
Dic
hlora
min
e
89%
0%11%
1. Hypochlorous acid
2. Hypochlorite ion
3. Dichloramine
1. Hypochlorous acid
2. Hypochlorite ion
3. Dichloramine
HOCL?HOCL?
Com
mon a
t pH <
6
Most
power
ful/e
ffect
...
All
of the
above
0%
95%
5%
1. Common at pH < 6
2. Most powerful/effective disinfectant
3. All of the above
1. Common at pH < 6
2. Most powerful/effective disinfectant
3. All of the above
NH2ClNH2Cl
Mono
chlo
ram
ine
Com
bined
Res
idua
l ...
Not a
s ef
fect
ive
as a
...
All
of the
above
6%
89%
6%0%
1. Monochloramine
2. Combined Residual Chlorine
3. Not as effective as a disinfectant as hypochlorus acid
4. All of the above
1. Monochloramine
2. Combined Residual Chlorine
3. Not as effective as a disinfectant as hypochlorus acid
4. All of the above
Sterilization only removes pathogenic organism from a
water sample?
Sterilization only removes pathogenic organism from a
water sample?
Tru
e
Fal
se
100%
0%
1. True
2. False
1. True
2. False
Chlorine AdvantagesChlorine Advantages1.Chlorine provides a strong residual in the
distribution system.
2.Chlorine can be easily converted to chloramines which also provide a strong residual and do not produce by-products.
3.Chlorine is easy to apply. Can use it in liquid, solid, or gas form
4.Chlorine is a relatively inexpensive disinfecting agent.
5.Chlorine is effective at low concentrations.
1.Chlorine provides a strong residual in the distribution system.
2.Chlorine can be easily converted to chloramines which also provide a strong residual and do not produce by-products.
3.Chlorine is easy to apply. Can use it in liquid, solid, or gas form
4.Chlorine is a relatively inexpensive disinfecting agent.
5.Chlorine is effective at low concentrations.
Chlorine DisadvantagesChlorine Disadvantages1.When chlorine reacts with organic material its'
concentration is reduced and trihalomethanes(THM's), haloacetic acids (HAA5), chlorite (when chlorine dioxide is used) and bromate (when ozone is used) are disinfection-by-products (DBP's). These compounds are carcinogenic.
2.Chlorine provides poor Cryptosporidium and Giardia control.
3.Effectiveness varies depending on turbidity, [ammonia], pH, etc.
4.Chlorine is a dangerous and potentially fatal chemical if used improperly
1.When chlorine reacts with organic material its' concentration is reduced and trihalomethanes(THM's), haloacetic acids (HAA5), chlorite (when chlorine dioxide is used) and bromate (when ozone is used) are disinfection-by-products (DBP's). These compounds are carcinogenic.
2.Chlorine provides poor Cryptosporidium and Giardia control.
3.Effectiveness varies depending on turbidity, [ammonia], pH, etc.
4.Chlorine is a dangerous and potentially fatal chemical if used improperly
According to the Stage 1 Disinfectant/Disinfection
Byproducts Rule which of the following are considered
haloacetic acids (HAA5) DPBs disinfectant byproducts?
According to the Stage 1 Disinfectant/Disinfection
Byproducts Rule which of the following are considered
haloacetic acids (HAA5) DPBs disinfectant byproducts?
Mono
chlo
roac
et...
Dic
hloro
acet
ic...
Mono
brom
oacet
i...
All
of the
abo...
0%
92%
4%4%
1. Monochloroacetic acid
2. Dichloroacetic acid
3. Monobromoacetic acid
4. All of the above
1. Monochloroacetic acid
2. Dichloroacetic acid
3. Monobromoacetic acid
4. All of the above
An advantage of chlorine is that it can be a liquid, solid, or a
gas?
An advantage of chlorine is that it can be a liquid, solid, or a
gas?
Tru
e
Fal
se
0%
100%1. True
2. False
1. True
2. False
Chlorine can completely remove Giardia and Cryptosporidium
from water?
Chlorine can completely remove Giardia and Cryptosporidium
from water?
Tru
e
Fal
se
100%
0%
1. True
2. False
1. True
2. False
Chlorine Disinfection TimelineChlorine Disinfection Timeline500 BC- Boiling of water recommended by Hippocrates
1879- Chlorine was applied as a disinfectant for the first time (England).
1893-First time chlorine applied on a plant scale basis (Hamburg, Germany).
1903- First time chlorine gas was used as a disinfectant in drinking water (Middlekerke, Belgium).
1908- The first full scale chlorine installation at a drinking water plant in the United States was initiated in this year.
(Bubbly Creek Filter Plant in Chicago)
500 BC- Boiling of water recommended by Hippocrates
1879- Chlorine was applied as a disinfectant for the first time (England).
1893-First time chlorine applied on a plant scale basis (Hamburg, Germany).
1903- First time chlorine gas was used as a disinfectant in drinking water (Middlekerke, Belgium).
1908- The first full scale chlorine installation at a drinking water plant in the United States was initiated in this year.
(Bubbly Creek Filter Plant in Chicago)
Chlorine Chemistry TimelineChlorine Chemistry Timeline1744- S.W. Scheele, a Swedish chemist, discovers chlorine.
1810-Chlorine was identified as a chemical element by Davey and called Chlorine (chlorous) due to its pale yellow/green color
1909 Liquid chlorine bleach becomes available after the Niagara Starch Co. in NY develops a production method.
1914-Wallace and Tiernan develop chlorine gas feed equipment
1914 CR Cox describes experiments with chlorine that are called “double chlorination” (Discovered breakpoint)
1928 The Olin Corporation begins production of High Test Hypochlorite dubbed “HTH”
1744- S.W. Scheele, a Swedish chemist, discovers chlorine.
1810-Chlorine was identified as a chemical element by Davey and called Chlorine (chlorous) due to its pale yellow/green color
1909 Liquid chlorine bleach becomes available after the Niagara Starch Co. in NY develops a production method.
1914-Wallace and Tiernan develop chlorine gas feed equipment
1914 CR Cox describes experiments with chlorine that are called “double chlorination” (Discovered breakpoint)
1928 The Olin Corporation begins production of High Test Hypochlorite dubbed “HTH”
http://ewr.cee.vt.edu/environmental/teach/wtprimer/chlorine/chlorine.html#History
Chlorination Methods TimelineChlorination Methods Timeline1939- A.E. Griffin explains “Breakpoint Chlorination”1942-Henry Marks invents the amperometric chlorine residual analyzer.
1973-JJ Rook discovers chloroform (trtihalomethane) in drinking water in New Orleans and Corvallis.
1974- the SDWA is passed into law by congress.
1986 -The Surface Water Treatment Rule requires disinfection of all surface water and groundwater under the influence of surface water (GWUISW)
1986- USEPA approves four methods of drinking water disinfection. Disinfection C•T requirements for each disinfectant are established to insure inactivation of Giardia and viruses
-Chlorination, Chloramines, Ozone, UV light
2003- USEPA approves UV disinfection for Crypto
1939- A.E. Griffin explains “Breakpoint Chlorination”1942-Henry Marks invents the amperometric chlorine residual analyzer.
1973-JJ Rook discovers chloroform (trtihalomethane) in drinking water in New Orleans and Corvallis.
1974- the SDWA is passed into law by congress.
1986 -The Surface Water Treatment Rule requires disinfection of all surface water and groundwater under the influence of surface water (GWUISW)
1986- USEPA approves four methods of drinking water disinfection. Disinfection C•T requirements for each disinfectant are established to insure inactivation of Giardia and viruses
-Chlorination, Chloramines, Ozone, UV light
2003- USEPA approves UV disinfection for Crypto
http://ewr.cee.vt.edu/environmental/teach/wtprimer/chlorine/chlorine.html#History
SDWA AmendmentsSDWA AmendmentsDecember 16,1998 promulgatedDisinfection Byproduct Rule (DBPR): Stage 1 DBPR **Stage 2 in the works!**• MCLs for trihalomethanes, haloacetic acids, bromate, and chlorite. • Maximum residual disinfectant level goals (MRDLs) were also finalized for
chlorine, chloramines, and chlorine dioxide.
“Community water systems and non-transient non-community systems, including those serving fewer than 10,000 people, that add a disinfectant to the drinking water during any part of the treatment process.”
MRDLGs for chlorine (4 mg/L), chloramines (4 mg/L), and chlorine dioxide (0.8 mg/L);
• MCLs for total trihalomethanes - a sum of the four listed above (0.080 mg/L), haloacetic acids (HAA5) (0.060 mg/L)- a sum of the two listed above plus monochloroacetic acid and mono- and dibromoacetic acids), and two inorganic disinfection byproducts (chlorite (1.0 mg/L)) and bromate (0.010 mg/L));
December 16,1998 promulgatedDisinfection Byproduct Rule (DBPR): Stage 1 DBPR **Stage 2 in the works!**• MCLs for trihalomethanes, haloacetic acids, bromate, and chlorite. • Maximum residual disinfectant level goals (MRDLs) were also finalized for
chlorine, chloramines, and chlorine dioxide.
“Community water systems and non-transient non-community systems, including those serving fewer than 10,000 people, that add a disinfectant to the drinking water during any part of the treatment process.”
MRDLGs for chlorine (4 mg/L), chloramines (4 mg/L), and chlorine dioxide (0.8 mg/L);
• MCLs for total trihalomethanes - a sum of the four listed above (0.080 mg/L), haloacetic acids (HAA5) (0.060 mg/L)- a sum of the two listed above plus monochloroacetic acid and mono- and dibromoacetic acids), and two inorganic disinfection byproducts (chlorite (1.0 mg/L)) and bromate (0.010 mg/L));
SDWA AmendmentsSDWA Amendments• May 1996- Information Collection Rule (ICR), occurrence data
for DBPs and precursors, microbials, water quality parameters, and treatment plant parameters.
Used to develop the Stage 2 DBPR and the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR).
• May 1996- Information Collection Rule (ICR), occurrence data for DBPs and precursors, microbials, water quality parameters, and treatment plant parameters.
Used to develop the Stage 2 DBPR and the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR).
Interim Enhanced Surface Water Treatment Rule -Applies to systems serving 10,000 or more people
Long Term 1 Enhanced Surface Water Treatment Rule -strengthen microbial controls for small systems (i.e., those systems serving fewer than 10,000 people.)
January 2002
SDWA AmendmentsSDWA AmendmentsJanuary 5, 2006 Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR).
All public water systems with surface water or groundwater under the influence of surface water.LT2 rule reduce illness linked with the contaminant Cryptosporidium and other disease-causing microorganisms in drinking water. Targets Cryptosporidium treatment requirements to higher risk systems.
•Targeting additional Cryptosporidium treatment requirements to higher risk systems •Requiring provisions to reduce risks from uncovered finished water storage facilities •Providing provisions to ensure that systems maintain microbial protection as they take steps to reduce the formation of disinfection byproduct
Chlorine was first used as a disinfectant in Europe in the late
1800s?
Chlorine was first used as a disinfectant in Europe in the late
1800s?
Tru
e
Fal
se
0%
100%
1. True
2. False
1. True
2. False
Ozone, UV light, Chlorination, and Chloramines are 4 EPA
approved disinfection methods?
Ozone, UV light, Chlorination, and Chloramines are 4 EPA
approved disinfection methods?
Tru
e
Fal
se
0%
100%1. True
2. False
1. True
2. False
Chlorine (Cl2)Chlorine (Cl2)• Widely distributed element• Most important use is bleach• Toxic, noncombustible, yellow-green gas with a
pungent, irritating odor and strong oxidizing effects• 2.5 times as dense as air!• Slightly soluble in water
– Combines with water to form hypochlorous acid (HOCl) and hydrochloric acid (HCl)
• Highly corrosive causes injury when the gas reacts with moisture in the body
• Widely distributed element• Most important use is bleach• Toxic, noncombustible, yellow-green gas with a
pungent, irritating odor and strong oxidizing effects• 2.5 times as dense as air!• Slightly soluble in water
– Combines with water to form hypochlorous acid (HOCl) and hydrochloric acid (HCl)
• Highly corrosive causes injury when the gas reacts with moisture in the body
Chlorine - ToxicityChlorine - Toxicity
• Major route of toxicity is inhalation
• Solutions that generate chlorine can be highly corrosive to skin or GI tract
• Strong oxidizing capability – Produce major tissue damage
• Major route of toxicity is inhalation
• Solutions that generate chlorine can be highly corrosive to skin or GI tract
• Strong oxidizing capability – Produce major tissue damage
Chlorine - ToxicityChlorine - Toxicity• Hypochlorous acid
– Penetrates cells and react with cytoplasmic proteins, enzymes
– Form N-chloro derivatives that destroy cell structure
– Can alter DNA replication of viruses
• Estimated lowest lethal concentration – 30-min exposure is 430 ppm -- 1000 ppm – Fatal within minutes
• Hypochlorous acid – Penetrates cells and react with
cytoplasmic proteins, enzymes– Form N-chloro derivatives that destroy
cell structure– Can alter DNA replication of viruses
• Estimated lowest lethal concentration – 30-min exposure is 430 ppm -- 1000 ppm – Fatal within minutes
Chlorine is a toxic, corrosive, gas?
Chlorine is a toxic, corrosive, gas?
Tru
e
Fal
se
0%
100%1. True
2. False
1. True
2. False
Which of the following is a correct set of characteristics for chlorine as used in disinfection?
Which of the following is a correct set of characteristics for chlorine as used in disinfection?
Chlo
rine
gas
i...
Chlo
rine
gas
i...
Chlo
rine
gas
i...
Chlo
rine
gas
i...
Chlo
rine
gas
i...
0% 0%
96%
0%4%
1. Chlorine gas is colorless, flammable, and heavier than air
2. Chlorine gas is colorless, flammable, and lighter than air
3. Chlorine gas is greenish-yellow (amber) in color, flammable, and lighter than air
4. Chlorine gas in greenish-yellow (amber) in color, toxic, lighter than air, and noncorrosive
5. Chlorine gas is toxic, corrosive, and heavier than air
1. Chlorine gas is colorless, flammable, and heavier than air
2. Chlorine gas is colorless, flammable, and lighter than air
3. Chlorine gas is greenish-yellow (amber) in color, flammable, and lighter than air
4. Chlorine gas in greenish-yellow (amber) in color, toxic, lighter than air, and noncorrosive
5. Chlorine gas is toxic, corrosive, and heavier than air
Protective EquipmentProtective Equipment
• Variety of rubber and plastic materials resist chlorine
• Wear protective clothing appropriate to the type and degree of contamination
• Use air-purifying or supplied-air respiratory equipment
• Chlorine-resistant plastic sheeting and disposable bags useful in preventing spread of contamination
• Variety of rubber and plastic materials resist chlorine
• Wear protective clothing appropriate to the type and degree of contamination
• Use air-purifying or supplied-air respiratory equipment
• Chlorine-resistant plastic sheeting and disposable bags useful in preventing spread of contamination
Protective EquipmentProtective Equipment
Chlorine ChemistryChlorine Chemistry• Chlorine Atom:
Atomic Number 17Atomic Weight 35.45 g
– Molecular Chlorine: Cl2• Yellow-green gas (above 100 ppm)• Chemical Classification
-"Oxidizer“, "Reactive“
********Two SMCL's apply to chlorine: 4 mg/l for Cl2, and 250mg/l for Cl-**New MCL under consideration
• Chlorine Atom:Atomic Number 17Atomic Weight 35.45 g
– Molecular Chlorine: Cl2• Yellow-green gas (above 100 ppm)• Chemical Classification
-"Oxidizer“, "Reactive“
********Two SMCL's apply to chlorine: 4 mg/l for Cl2, and 250mg/l for Cl-**New MCL under consideration
Chlorine Chemistry PropertiesChlorine Chemistry PropertiesDry liquid: 100% gas• Powder: Calcium Hypochlorite- 30, 65, 70% chlorine• Liquid: Sodium Hypochlorite: 5-15% chlorine
Density = 2.5 times as heavy as air, Irritant• Boiling point -29.9 oF• Freezing point -149.76 oF • 1 part of liquid will produce 450 parts of gas
Maximum solubility: 1% at 49.2 oF• Slightly soluble in water• Temperatures below 49.2 will result in chlorine ice• Insoluble in water at 212oF.
Dry liquid: 100% gas• Powder: Calcium Hypochlorite- 30, 65, 70% chlorine• Liquid: Sodium Hypochlorite: 5-15% chlorine
Density = 2.5 times as heavy as air, Irritant• Boiling point -29.9 oF• Freezing point -149.76 oF • 1 part of liquid will produce 450 parts of gas
Maximum solubility: 1% at 49.2 oF• Slightly soluble in water• Temperatures below 49.2 will result in chlorine ice• Insoluble in water at 212oF.
Where should sodium hypochlorite (liquid bleach) be
stored?
Where should sodium hypochlorite (liquid bleach) be
stored?
Away
from
flam
...
Aw
ay fr
om e
qu...
clo
sed
cont
ai...
Nea
r the
chem
i...
6%0%0%
94%1. Away from flammable objects, as it is a fire hazard
2. Away from equipment that is susceptible to corrosion
3. closed containers at room temperature for no longer than 6 months
4. Near the chemical feed pump day tank, to lessen operator handling risks
1. Away from flammable objects, as it is a fire hazard
2. Away from equipment that is susceptible to corrosion
3. closed containers at room temperature for no longer than 6 months
4. Near the chemical feed pump day tank, to lessen operator handling risks
Chlorine as a powder can have purities of 30, 65, and 70%?
Chlorine as a powder can have purities of 30, 65, and 70%?
Tru
e
Fal
se
11%
89%1. True
2. False
1. True
2. False
Sodium hypochlorite is manufactured by the reaction of gaseous or liquid chlorine with a solution of _________ _________
to produce a liquid containing NaOCl.
Sodium hypochlorite is manufactured by the reaction of gaseous or liquid chlorine with a solution of _________ _________
to produce a liquid containing NaOCl.
Sodiu
m h
ydro
xi...
Pota
ssiu
m h
ydr..
.
Pota
ssiu
m b
isu...
Sodiu
m a
zide
86%
0%0%
14%
1. Sodium hydroxide
2. Potassium hydroxide
3. Potassium bisulfite
4. Sodium azide
1. Sodium hydroxide
2. Potassium hydroxide
3. Potassium bisulfite
4. Sodium azide
Which form of hypochlorite is the most dangerous to handle? Which form of hypochlorite is
the most dangerous to handle?
Sodiu
m
Flu
oride
Cal
cium
Chlo
rine
36%
23%
27%
14%
1. Sodium
2. Fluoride
3. Calcium
4. Chlorine
1. Sodium
2. Fluoride
3. Calcium
4. Chlorine
Chlorine gas is _____ times heavier than air
Chlorine gas is _____ times heavier than air
2.5 2. 3.
51.
5
96%
0%0%4%
1. 2.5
2. 2.0
3. 3.5
4. 1.5
1. 2.5
2. 2.0
3. 3.5
4. 1.5
Chlorine ChemistryChlorine ChemistryWhen Cl combines with water it produces hypochlorous acid (HOCl) and hydrochloric acid (HCl).
Cl2 + H2O HOCl + HCl
When Cl combines with water it produces hypochlorous acid (HOCl) and hydrochloric acid (HCl).
Cl2 + H2O HOCl + HCl
hypochlorous acid and hypochlorite (OCL-) ion vary with pH.
Both HOCl and OCl are good disinfecting agents, but un-ionized hypochlorous acid (HOCl) is 100 times more effective than hypochlorite (OCl-)
HOCL is stable below pH 6
hypochlorous acid and hypochlorite (OCL-) ion vary with pH.
Both HOCl and OCl are good disinfecting agents, but un-ionized hypochlorous acid (HOCl) is 100 times more effective than hypochlorite (OCl-)
HOCL is stable below pH 6
http://ewr.cee.vt.edu/environmental/teach/wtprimer/chlorine/chlorine.html
Hypochlorous acid is the most powerful disinfectant associated
with chlorine?
Hypochlorous acid is the most powerful disinfectant associated
with chlorine?
Tru
e
Fal
se
0%
100%1. True
2. False
1. True
2. False
pH Impact on Free ChlorinepH Impact on Free Chlorine
http://ewr.cee.vt.edu/environmental/teach/wtprimer/chlorine/chlorine.html
What compound is first formed when chlorine is applied to
water?
What compound is first formed when chlorine is applied to
water?
Hyp
ochlo
rous
a...
Hyd
roch
loric
a...
Chlo
ram
ines
Fre
e ch
lorin
e ...
75%
4%
17%
4%
1. Hypochlorous acid
2. Hydrochloric acid
3. Chloramines
4. Free chlorine ions
1. Hypochlorous acid
2. Hydrochloric acid
3. Chloramines
4. Free chlorine ions
Chlorine will destroy bacteria most rapidly at what pH?
Chlorine will destroy bacteria most rapidly at what pH?
7.5
8.5
9.5
10.5
100%
0%0%0%
1. 7.5
2. 8.5
3. 9.5
4. 10.5
1. 7.5
2. 8.5
3. 9.5
4. 10.5
Chlorine Chemistry in WaterChlorine Chemistry in Water
1. Start with chlorine gas Cl2 + H2O HOCl + HCl
2. If the pH of the water is greater than 8, the hypochlorus acid (HOCl-) will dissociate (break) to yield hypochlorite ion.
HOCl H+ + OCl– @pH>8
3. pH is less than 7, HOCl will not dissociate.
1. Start with chlorine gas Cl2 + H2O HOCl + HCl
2. If the pH of the water is greater than 8, the hypochlorus acid (HOCl-) will dissociate (break) to yield hypochlorite ion.
HOCl H+ + OCl– @pH>8
3. pH is less than 7, HOCl will not dissociate.
http://ewr.cee.vt.edu/environmental/teach/wtprimer/chlorine/chlorine.html
HOClHOClHOClHOCl @pH<7@pH<7
Free residual hypochlorous acid (HOCl) is more 1000 times more effective than combined residual monochloramine
Free residual hypochlorous acid (HOCl) is more 1000 times more effective than combined residual monochloramine
Which of the following is true about chlorine chemistry?
Which of the following is true about chlorine chemistry?
pH <
7 fa
vors
hyp
oc...
pH >
8 hyp
ochlo
rite
i...
HOCL is
100
tim
es m
o..
All
of the
above
100%
0%0%0%
1. pH < 7 favors hypochlorous acid
2. pH >8 hypochlorite ions form which can still disinfectant
3. HOCL is 100 times more powerful then OCL-
4. All of the above
1. pH < 7 favors hypochlorous acid
2. pH >8 hypochlorite ions form which can still disinfectant
3. HOCL is 100 times more powerful then OCL-
4. All of the above
HOCL is 1,000 times more powerful then monochloramine?
HOCL is 1,000 times more powerful then monochloramine?
Tru
e
Fal
se
6%
94%
1. True
2. False
1. True
2. False
Basic Chlorine CompoundsBasic Chlorine Compounds
Chlorine Demand: chlorine reacted with – Clay, silt, iron, manganese, bacteria
Combined Chlorine ResidualsChloramines: chlorine reacted with
– Inorganic ammonia compounds (NH3)– Organic nitrogen proteins (amino acids)– Less DBP– Weak against virus and protozoa
Chlorine Demand: chlorine reacted with – Clay, silt, iron, manganese, bacteria
Combined Chlorine ResidualsChloramines: chlorine reacted with
– Inorganic ammonia compounds (NH3)– Organic nitrogen proteins (amino acids)– Less DBP– Weak against virus and protozoa
Chlorine demand is satisfied at the point when
Chlorine demand is satisfied at the point when
The
reac
tion
o...
Fre
e ch
lorin
e ...
An o
dor o
f chl
...
Chlo
rine
reac
h...
96%
0%0%4%
1. The reaction of chlorine with organic and inorganic materials stops
2. Free chlorine residuals reach 2.5 mg/L
3. An odor of chlorine is present
4. Chlorine reaches the last tap
1. The reaction of chlorine with organic and inorganic materials stops
2. Free chlorine residuals reach 2.5 mg/L
3. An odor of chlorine is present
4. Chlorine reaches the last tap
Cl:NH3 and pH Impact in WaterCl:NH3 and pH Impact in Water
http://ewr.cee.vt.edu/environmental/teach/wtprimer/chlorine/chlorine.html
1. If ammonia (NH3) is present in water, the hypochlorus acid (HOCL) will react to form one kind of chloramine depending on the pH, temperature, and reaction time.
1. If ammonia (NH3) is present in water, the hypochlorus acid (HOCL) will react to form one kind of chloramine depending on the pH, temperature, and reaction time.
2. Monochloramine and dichloramine are formed at pH 4.5 - 8.5
3. Monochloramine is most common @pH>7.5; Cl2:NH3 <5:1
4. pH 4-5-7.5, Cl:NH3 > 5:1 -Monochloramine converts to dichloramines
5. pH < 4.5, Cl2:NH3 ~15:1 -Trichloramine which produces a very foul odor.
2. Monochloramine and dichloramine are formed at pH 4.5 - 8.5
3. Monochloramine is most common @pH>7.5; Cl2:NH3 <5:1
4. pH 4-5-7.5, Cl:NH3 > 5:1 -Monochloramine converts to dichloramines
5. pH < 4.5, Cl2:NH3 ~15:1 -Trichloramine which produces a very foul odor.
Chlorine-Ammonia (chloramines)Chlorine-Ammonia (chloramines)
http://ewr.cee.vt.edu/environmental/teach/wtprimer/chlorine/chlorine.html
1. Rates of formation of mono and dichloramine.2. pH3. Temperature4. Time5. Cl:NH3 ratio
Fact: High Cl:NH3 ratio, low temp & pH favor dichloramine
Combined Available Chlorine- chlorine existing in the water in chemical combination with ammonia-nitrogen or organic nitrogen
1. Rates of formation of mono and dichloramine.2. pH3. Temperature4. Time5. Cl:NH3 ratio
Fact: High Cl:NH3 ratio, low temp & pH favor dichloramine
Combined Available Chlorine- chlorine existing in the water in chemical combination with ammonia-nitrogen or organic nitrogen
Chlorine- Ammonia reactions are governed by:Chlorine- Ammonia reactions are governed by:
Chloramines in WaterChloramines in Water
http://ewr.cee.vt.edu/environmental/teach/wtprimer/chlorine/chlorine.html
3. pH 4.5-8.5; pH 8.0-8.5 Monochloramine: NH3 + HOCl NH2Cl + H2O
2. pH 4.5-8.5; pH 4.5-8.0 Dichloramine: NH2Cl + 2HOCl NHCl2 + 2H2O
4. pH <4.5Trichloramine: NHCl2 + 3HOCl NHCl3 + 3H2O
3. pH 4.5-8.5; pH 8.0-8.5 Monochloramine: NH3 + HOCl NH2Cl + H2O
2. pH 4.5-8.5; pH 4.5-8.0 Dichloramine: NH2Cl + 2HOCl NHCl2 + 2H2O
4. pH <4.5Trichloramine: NHCl2 + 3HOCl NHCl3 + 3H2O
•Chloramines are an effective disinfectant against bacteria but not against viruses.
•Add more chlorine to the wastewater to prevent the formation of chloramines and form stronger disinfectants.
•Chloramines are an effective disinfectant against bacteria but not against viruses.
•Add more chlorine to the wastewater to prevent the formation of chloramines and form stronger disinfectants.
ChloraminesChloramines
Add the Extra Free Chlorine (HOCL)
Add the Extra Free Chlorine (HOCL)
http://ewr.cee.vt.edu/environmental/teach/wtprimer/chlorine/chlorine.html
5. Additional free chlorine (HOCL or OCL-) reacts with chloramine to produce hydrogen ion, water , and nitrogen gas which will come out of solution.
In the case of the monochloramine, the following reaction occurs:
2NH2Cl + HOCl N2 + 6HCl + H2O
Added free chlorine reduces the concentration of chloramines in the disinfection process. Instead the chlorine that is added is allowed to form the stronger disinfectant, hypochlorus acid.
5. Additional free chlorine (HOCL or OCL-) reacts with chloramine to produce hydrogen ion, water , and nitrogen gas which will come out of solution.
In the case of the monochloramine, the following reaction occurs:
2NH2Cl + HOCl N2 + 6HCl + H2O
Added free chlorine reduces the concentration of chloramines in the disinfection process. Instead the chlorine that is added is allowed to form the stronger disinfectant, hypochlorus acid.
If abundant (15 times) Cl is around and the pH < 4.5
Trichloramine is the most likely chloramine to form?
If abundant (15 times) Cl is around and the pH < 4.5
Trichloramine is the most likely chloramine to form?
Tru
e
Fal
se
10%
90%1. True
2. False
1. True
2. False
Which of the following impact chloramine disinfection?
Which of the following impact chloramine disinfection?
pH
Tem
perat
ure
Tim
e
All
of the
above
0%
100%
0%0%
1. pH
2. Temperature
3. Time
4. All of the above
1. pH
2. Temperature
3. Time
4. All of the above
Ammonium nitrogen and chlorine
Ammonium nitrogen and chlorine
Taste and Odor ProblemsTaste and Odor Problems
• Free (HOCL) 20 mg/L
• Monochloramine 5 mg/L
• Dichloramine .8 mg/L
• Trichloramine .02 mg/L
• Free (HOCL) 20 mg/L
• Monochloramine 5 mg/L
• Dichloramine .8 mg/L
• Trichloramine .02 mg/L
Chlorine Chemistry SummaryChlorine Chemistry SummaryCl2 + H2O HCl + HOClChlorine Hydrochloric Hypochlorous
Ca(OCl)2 (aqueous) Ca2+ +2 OCl-
Calcium Hypochlorite Hypochlorite
NaOCl2 (aqueous) Na+ + OCl-
Sodium Hypochlorite Hypochlorite
HOCl H+ + OCl-
Hypochlorous Hypochlorite
HOCl + NH3 NH2Cl + H2OHypochlorous Ammonia Chloramine
Cl2 + H2O HCl + HOClChlorine Hydrochloric Hypochlorous
Ca(OCl)2 (aqueous) Ca2+ +2 OCl-
Calcium Hypochlorite Hypochlorite
NaOCl2 (aqueous) Na+ + OCl-
Sodium Hypochlorite Hypochlorite
HOCl H+ + OCl-
Hypochlorous Hypochlorite
HOCl + NH3 NH2Cl + H2OHypochlorous Ammonia Chloramine
Chlorine Residual AnalysisChlorine Residual Analysis• Starch Iodide Titration: common in wastewater
• Amperometric Titration: common in wastewater with cloudy or turbidity problems
• DPD colorometric- common in water and wastewater. Measures free residual or combined residual.
• Starch Iodide Titration: common in wastewater
• Amperometric Titration: common in wastewater with cloudy or turbidity problems
• DPD colorometric- common in water and wastewater. Measures free residual or combined residual.
Chlorine residual may be determined using the reagent:
Chlorine residual may be determined using the reagent:
Die
thyl
-p-p
hen...
Eth
ylen
e dia
mi..
.
Poly
chlo
rinat
e...
Sodiu
m th
iosu
l...
100%
0%0%0%
1. Diethyl-p-phenylene diamine
2. Ethylene diamine tetraacetic acid
3. Polychlorinated biphenyls
4. Sodium thiosulfate
1. Diethyl-p-phenylene diamine
2. Ethylene diamine tetraacetic acid
3. Polychlorinated biphenyls
4. Sodium thiosulfate
Which of the following methods is not used to determine chlorine
residual?
Which of the following methods is not used to determine chlorine
residual?
Photo
met
ric
Iodo
met
ric
Titr
imet
ric
Am
perom
etric
70%
25%
5%0%
1. Photometric
2. Iodometric
3. Titrimetric
4. Amperometric
1. Photometric
2. Iodometric
3. Titrimetric
4. Amperometric
A chlorine demand test will show the:
A chlorine demand test will show the:
Saf
e am
ount o
f...
Num
ber o
f lbs
...
Am
ount of c
hlo...
Am
ount of c
hlo...
0% 0%
100%
0%
1. Safe amount of chlorine that may be fed without killing people
2. Number of lbs required to kill 100% of coliforms
3. Amount of chlorine required to give a desired residual after a given time
4. Amount of chlorine required to satisfy the biochemical oxygen demand
1. Safe amount of chlorine that may be fed without killing people
2. Number of lbs required to kill 100% of coliforms
3. Amount of chlorine required to give a desired residual after a given time
4. Amount of chlorine required to satisfy the biochemical oxygen demand
Breakpoint ChlorinationBreakpoint ChlorinationBreakpoint chlorination: The point at which near complete oxidation of nitrogen
compounds are reached . Any point beyond breakpoint is mostly free chlorine (HOCL and OCL-)
A. Amount of chlorine required
Theory: 7.6 to 15 times the ammonia nitrogen content of the water
Practice: up to 25 times the ammonia nitrogen content
B. Beyond breakpoint
90% free residual chlorine (HOCL and OCL-)
10% combined chlorine
C. Why must breakpoint chlorination be reached?• Necessary for the production of free residual chlorine (HOCL and OCL -)• Reduces taste and odors• Reduces chloramines
Breakpoint chlorination: The point at which near complete oxidation of nitrogen compounds are reached . Any point beyond breakpoint is mostly free chlorine (HOCL and OCL-)
A. Amount of chlorine required
Theory: 7.6 to 15 times the ammonia nitrogen content of the water
Practice: up to 25 times the ammonia nitrogen content
B. Beyond breakpoint
90% free residual chlorine (HOCL and OCL-)
10% combined chlorine
C. Why must breakpoint chlorination be reached?• Necessary for the production of free residual chlorine (HOCL and OCL -)• Reduces taste and odors• Reduces chloramines
What is the process of adding chlorine to water until the chlorine demand has been
satisfied called?
What is the process of adding chlorine to water until the chlorine demand has been
satisfied called?
Conta
ct ti
me
Rel
ique
fact
ion
Hyp
ochlo
rinat
i...
Bre
akpoi
nt chl..
.
0%
100%
0%0%
1. Contact time
2. Reliquefaction
3. Hypochlorination
4. Breakpoint chlorination
1. Contact time
2. Reliquefaction
3. Hypochlorination
4. Breakpoint chlorination
Breakpoint ChlorinationBreakpoint ChlorinationZone I: Chlorine is destroyed by reducing agents such as iron,
manganese, clay and silt. Chlorine reduced to chloride
Zone II: Chlorine comes into contact with organics and ammonia. Chloroorganics and chloramines are formed.
Zone III: Chloroorganics and chloramines are partially destroyed. Chloramines are broken down and converted to nitrogen gas which leaves the system
Zone IV: Breakpoint. Beyond this point, free available residual is formed. Some chloroorganics still remain as combined residual.
Chlorine demand is difference between applied chlorine and the free chlorine residual at any two points on the breakpoint curve.
Zone I: Chlorine is destroyed by reducing agents such as iron, manganese, clay and silt. Chlorine reduced to chloride
Zone II: Chlorine comes into contact with organics and ammonia. Chloroorganics and chloramines are formed.
Zone III: Chloroorganics and chloramines are partially destroyed. Chloramines are broken down and converted to nitrogen gas which leaves the system
Zone IV: Breakpoint. Beyond this point, free available residual is formed. Some chloroorganics still remain as combined residual.
Chlorine demand is difference between applied chlorine and the free chlorine residual at any two points on the breakpoint curve.
In Zone 1 most of the chlorine dose gets used by chlorine
demand ?
In Zone 1 most of the chlorine dose gets used by chlorine
demand ?
Tru
e
Fal
se
0%
100%1. True
2. False
1. True
2. False
In Zone II chlorine reacts with ammonia to form combined
chlorine ?
In Zone II chlorine reacts with ammonia to form combined
chlorine ?
Tru
e
Fal
se
22%
78%1. True
2. False
1. True
2. False
In Zone III some combined chlorine gets broken down to
nitrogen gas ?
In Zone III some combined chlorine gets broken down to
nitrogen gas ?
Tru
e
Fal
se
0%
100%1. True
2. False
1. True
2. False
At Breakpoint chlorine added becomes free available chlorine?
At Breakpoint chlorine added becomes free available chlorine?
Tru
e
Fal
se
0%
100%1. True
2. False
1. True
2. False
Disinfection with chlorine may cause the formation of these
compounds. They are a result of chlorine binding to naturally
occurring organic matter.
Disinfection with chlorine may cause the formation of these
compounds. They are a result of chlorine binding to naturally
occurring organic matter.
Trih
alom
ethan
e...
Tric
hlora
min
es
CFCs
Chlo
roal
kali
s...
54%
0%0%
46%
1. Trihalomethanes
2. Trichloramines
3. CFCs
4. Chloroalkali salts
1. Trihalomethanes
2. Trichloramines
3. CFCs
4. Chloroalkali salts
DPB (TRIHALOMETHANES)DPB (TRIHALOMETHANES)• THM: Carcinogenic byproduct of a reaction with chlorine. Form when
free chlorine comes into contact with organic compounds. ID by EPA in 1974.
A. Four most common THMs MCLS• Chloroform 0 mg/L• Bromodichloromethane 0 mg/L• Dibromochloromethane 0.06 mg/L• Bromoform 0 mg/L
C. DPB• Trihalomethanes, haloacetonitriles, chlorinated acetic acids,
chlorophenolds,
• THM: Carcinogenic byproduct of a reaction with chlorine. Form when free chlorine comes into contact with organic compounds. ID by EPA in 1974.
A. Four most common THMs MCLS• Chloroform 0 mg/L• Bromodichloromethane 0 mg/L• Dibromochloromethane 0.06 mg/L• Bromoform 0 mg/L
C. DPB• Trihalomethanes, haloacetonitriles, chlorinated acetic acids,
chlorophenolds,
Bromoform is a type of trihalomethane?
Bromoform is a type of trihalomethane?
Tru
e
Fal
se
0%
100%1. True
2. False
1. True
2. False
TRIHALOMETHANESTRIHALOMETHANES
•Chloroform•Bromodichloromethane•Bromoform
•MCL=0.08 mg/L
•Chloroform•Bromodichloromethane•Bromoform
•MCL=0.08 mg/L CC
XX
XX
XX
HH
X= Cl, Br, or I X= Cl, Br, or I
HCX3HCX3
DPB (TRIHALOMETHANES)DPB (TRIHALOMETHANES)D. Water treatment processes that can be used to control THMs.• Aeration• Feed oxidation chemicals instead of pre chlorination • Coagulation, flocculation, sedimentation, and filtration• Water softening processes (Ion exchange)• Powdered activated carbon.
E. Substitute Oxidants for Pre-chlorinations
• Ozone O3 Potassium permangante KMnO4
• Hydrogen peroxide H2O2 hypochlorous acid HOCl
• Hypobromous Acid HOBr Bromine Br
• Hypoiodous acid HOIChlorine Dioxide ClO2
• Iodine I2 Oxygen O2
D. Water treatment processes that can be used to control THMs.• Aeration• Feed oxidation chemicals instead of pre chlorination • Coagulation, flocculation, sedimentation, and filtration• Water softening processes (Ion exchange)• Powdered activated carbon.
E. Substitute Oxidants for Pre-chlorinations
• Ozone O3 Potassium permangante KMnO4
• Hydrogen peroxide H2O2 hypochlorous acid HOCl
• Hypobromous Acid HOBr Bromine Br
• Hypoiodous acid HOIChlorine Dioxide ClO2
• Iodine I2 Oxygen O2
You can aerate or add oxygen to water before chlorination to cut
THMS?
You can aerate or add oxygen to water before chlorination to cut
THMS?
Tru
e
Fal
se
6%
94%
1. True
2. False
1. True
2. False
Chlorine EffectivenessChlorine EffectivenessThese are all important:
1.pH
2.Temperature
3.Chlorine Demand:
4.suspended solids/nitrite/organics/
reduced chemicals
5. Contact time
6. Concentration
7. Mixing Intensity
8. Type of residual
These are all important:
1.pH
2.Temperature
3.Chlorine Demand:
4.suspended solids/nitrite/organics/
reduced chemicals
5. Contact time
6. Concentration
7. Mixing Intensity
8. Type of residual
Chlorine EffectivenessChlorine Effectiveness1. pH (low pH =better disinfection) • want pH < 7.5=more hypochlorus acid
2. Temperature (warm temp=better disinfect)• chlorine disinfection power doubles every 10 degrees.
3. Chlorine Demand (Low Chlorine demand=better disinfect)
• Fe+3, Mn+4, HS and turbidity cause chlorine demand
4. Suspended solids/nitrite/organics/
reduced chemicals
1. pH (low pH =better disinfection) • want pH < 7.5=more hypochlorus acid
2. Temperature (warm temp=better disinfect)• chlorine disinfection power doubles every 10 degrees.
3. Chlorine Demand (Low Chlorine demand=better disinfect)
• Fe+3, Mn+4, HS and turbidity cause chlorine demand
4. Suspended solids/nitrite/organics/
reduced chemicals
As water temperatures decrease, the disinfecting action of
chlorine
As water temperatures decrease, the disinfecting action of
chlorine
Dec
reas
es
Incr
ease
s
Rem
ains
the
sam
e
94%
0%6%
1. Decreases
2. Increases
3. Remains the same
1. Decreases
2. Increases
3. Remains the same
In the application of chlorine for disinfection, which of the
following is not normally an operational consideration?
In the application of chlorine for disinfection, which of the
following is not normally an operational consideration?
Mix
ing
Conta
ct ti
me
Dis
solv
ed o
xyg...
pH
None
of the
se ..
.
14%
0%
32%
0%
55%
1. Mixing
2. Contact time
3. Dissolved oxygen
4. pH
5. None of these answers are correct
1. Mixing
2. Contact time
3. Dissolved oxygen
4. pH
5. None of these answers are correct
pH > 8 favors hypochlorite ion which is a more powerful
disinfectant than hypochlorous acid?
pH > 8 favors hypochlorite ion which is a more powerful
disinfectant than hypochlorous acid?
Tru
e
Fal
se
93%
7%
1. True
2. False
1. True
2. False
Chlorine disinfection power doubles every 10 degrees?Chlorine disinfection power doubles every 10 degrees?
Tru
e
Fal
se
7%
93%
1. True
2. False
1. True
2. False
Low chlorine demand is better for disinfection?
Low chlorine demand is better for disinfection?
Tru
e
Fal
se
0%
100%1. True
2. False
1. True
2. False
Chlorine EffectivenessChlorine Effectiveness5. Contact time (longer contact = better disinfection)• Varies depending on tank dimensions
6. Concentration (higher concentration=better disinfection)• OPTIMIZE THE DISINFECTION PROCESS
7. Mixing Intensity (Rapid Mixing=better disinfection)• Rapidly disperse chlorine better kill rate
8. Disinfection CT (higher actual CT=better disinfection)• As disinfection CT increases by 50, effective kill
increases 10 times (EPA set guidelines)
5. Contact time (longer contact = better disinfection)• Varies depending on tank dimensions
6. Concentration (higher concentration=better disinfection)• OPTIMIZE THE DISINFECTION PROCESS
7. Mixing Intensity (Rapid Mixing=better disinfection)• Rapidly disperse chlorine better kill rate
8. Disinfection CT (higher actual CT=better disinfection)• As disinfection CT increases by 50, effective kill
increases 10 times (EPA set guidelines)
Longer contact time is better for disinfection?
Longer contact time is better for disinfection?
Tru
e
Fal
se
0%
100%1. True
2. False
1. True
2. False
In general high dose concentrations = better
disinfection?
In general high dose concentrations = better
disinfection?
Tru
e
Fal
se
13%
87%1. True
2. False
1. True
2. False
Slow mixing favors better disinfection?
Slow mixing favors better disinfection?
Tru
e
Fal
se
85%
15%
1. True
2. False
1. True
2. False
SDWASDWA
99.9% removal of Giardia Lamblia cysts
99.99% removal of Enteric Viruses
Disinfection CTs have been established
Free chlorine
Chloramine
Chlorine dioxide
Ozone
99.9% removal of Giardia Lamblia cysts
99.99% removal of Enteric Viruses
Disinfection CTs have been established
Free chlorine
Chloramine
Chlorine dioxide
Ozone
LogLogUnderstanding “log removal” requirements of the Long Term 1 Enhanced Surface Water Treatment RuleFirst a definition and some examples:Logarithm10: The exponent of the power to which 10 must be raised to equal a given number.
Examples:• 102 is equal to 100, the log10 of 100 is 2• 103 is equal to 1000, the log10 of 1000 is 3• 102.65 is equal to 446.7, the log10 of 446.7 is 2.65
Log inactivation: A simplified method for expressing the degreeto which microorganisms are removed from water. The removalpercentage is expressed as the log to the base 10.
Examples:If 100 Giardia cysts are inactivated so that only 1 remains, what is the percent removal of the microorganism?(100 - 1) x 100 = 99% or 2 log inactivation100
Understanding “log removal” requirements of the Long Term 1 Enhanced Surface Water Treatment RuleFirst a definition and some examples:Logarithm10: The exponent of the power to which 10 must be raised to equal a given number.
Examples:• 102 is equal to 100, the log10 of 100 is 2• 103 is equal to 1000, the log10 of 1000 is 3• 102.65 is equal to 446.7, the log10 of 446.7 is 2.65
Log inactivation: A simplified method for expressing the degreeto which microorganisms are removed from water. The removalpercentage is expressed as the log to the base 10.
Examples:If 100 Giardia cysts are inactivated so that only 1 remains, what is the percent removal of the microorganism?(100 - 1) x 100 = 99% or 2 log inactivation100
Inactivation of Waterborne Pathogens By DisinfectionThe EPA has approved 4 chemical oxidizers for drinking
water
Disinfection:1. Free Chlorine, (HOCl and OCl-)2. Chloramine, (NH2Cl)3. Chlorine dioxide, (ClO2)4. Ozone (O3)
Each of these disinfectants has a proven capability to kill orinactivate waterborne pathogens, including viruses and
protozoa cysts. The disinfection power of these chemicals is dramatically different.
Inactivation of Waterborne Pathogens By DisinfectionThe EPA has approved 4 chemical oxidizers for drinking
water
Disinfection:1. Free Chlorine, (HOCl and OCl-)2. Chloramine, (NH2Cl)3. Chlorine dioxide, (ClO2)4. Ozone (O3)
Each of these disinfectants has a proven capability to kill orinactivate waterborne pathogens, including viruses and
protozoa cysts. The disinfection power of these chemicals is dramatically different. Disinfection C•TDisinfection C•T
EPA APPROVED METHODSEPA APPROVED METHODS
Four EPA Approved disinfectant chemicals are Free Chlorine, (HOCl and OCl-)
Chloramine, (NH2Cl)Chlorine dioxide, (ClO2)
Ozone (O3)?
Four EPA Approved disinfectant chemicals are Free Chlorine, (HOCl and OCl-)
Chloramine, (NH2Cl)Chlorine dioxide, (ClO2)
Ozone (O3)?
Tru
e
Fal
se
0%
100%
1. True
2. False
1. True
2. False
Disinfection C•T Requirements Disinfection C•T Requirements
Chlorine residual concentrations (mg/L)
Contact Time (min)
Water Temperature
Water pH
Disinfection power= [residual chlorine] • time of its contact
Chlorine residual concentrations (mg/L)
Contact Time (min)
Water Temperature
Water pH
Disinfection power= [residual chlorine] • time of its contact
Disinfection C•T CalculationDisinfection C•T CalculationC•T= [disinfection concentration mg/L] • contact time (min)
C•T units= mg/L• min or mg •min/L
Required C•TCTrequired is # established by EPA to provide log inactivation. Based on Giardia
cysts. Look up in charts
Actual C•TCTactual is # established by multiplying actual chlorine residual by hydraulic
detention time and baffle factor.
C•T= [disinfection concentration mg/L] • contact time (min)
C•T units= mg/L• min or mg •min/L
Required C•TCTrequired is # established by EPA to provide log inactivation. Based on Giardia
cysts. Look up in charts
Actual C•TCTactual is # established by multiplying actual chlorine residual by hydraulic
detention time and baffle factor.
Disinfection C•T CalculationDisinfection C•T Calculation
C•T actual =[Residual chlorine]•hydraulic detention time•baffle factor (table)
Hydraulic detention time = volume/flow rate
C•Tact/ CTreq= ratio must be > or = to 1.
C•Tact/ CTreq>1.0
C•T actual =[Residual chlorine]•hydraulic detention time•baffle factor (table)
Hydraulic detention time = volume/flow rate
C•Tact/ CTreq= ratio must be > or = to 1.
C•Tact/ CTreq>1.0
Disinfection C•T RulesDisinfection C•T Rules1.Chlorine residuals used for C•T
calculations are measured after contact, but before first customer.
2. Contact times are determined by calculating the hydraulic detention time (HDT) as water flows through pipes and tanks. Based on highest flow of day.
1.Chlorine residuals used for C•T calculations are measured after contact, but before first customer.
2. Contact times are determined by calculating the hydraulic detention time (HDT) as water flows through pipes and tanks. Based on highest flow of day.
Disinfection C•T RulesDisinfection C•T Rules
3. Water flowing through pipes provides contact times that are equal to the calculated HDT. Circular or rectangular tanks used for contact time are given only partial credit due to short circuiting.
3. Water flowing through pipes provides contact times that are equal to the calculated HDT. Circular or rectangular tanks used for contact time are given only partial credit due to short circuiting.
The objective stated in the syllabus to have an overview of chlorine
chemistry and the chlorination process, were met ?
The objective stated in the syllabus to have an overview of chlorine
chemistry and the chlorination process, were met ?
Stro
ngly A
gree
Agre
e
Dis
agre
e
Stro
ngly D
isag
ree
0% 0%0%0%
1. Strongly Agree
2. Agree
3. Disagree
4. Strongly Disagree
1. Strongly Agree
2. Agree
3. Disagree
4. Strongly Disagree