TCEQ Class B Surface Water B Test Material | Water Operator Certification Exam Prep
Explain and expand on Chlorine Dioxide (what it reacts Chlorine Dioxide is a gas used in small quantities to disinfect water. It does not
with, oxidizes, etc) react with organics to form THMs and HAAs. It oxidizes phenols, manganese,
iron, sulfurous and organic compounds which aids in the removal of tastes and
odors. It is a very effective bactericide and a superior virocide. It dies not
combine with ammonia. Chlorine Dioxide MRDL is .8 mg/L and monitoring
procedures are the same as for chlorine. The Chlorite MCL is .q mg/L and must
be monitored daily.
What is texas drinking water pH requirements? The texas drinking water requirements require a pH > 7.0 for the water
treatment plant finished water. EPA requires that pH analysis be preformed
within 15 minutes of the sample being caught.
How does pH affect Chlorine activity? When chlorine is added to water it forms hypochlorous acid (HOCL) and
hydrochloric acid (OCL). The hypochlorous acid is the effective disinfectant. At
a pH of 4.0 there is 100% hypochlorous acid. At a pH of 11 there is 100%
hypochlorite ion. At a pH of 7, the hypochlorous acid is at about 80% and the
hypochlorite ion makes up about 20% of the chlorine content. The lower the
pH is more effective chlorine is because you have more hypochlorous acid.
What is meant by water stability? Stable water is defined as water that will neither deposit or dissolve a calcium
carbonate film or scale. Since no water is stable indefinitely, chemical treatment
of water usually is intended to produce water that is slightly scale forming
without being liable to cause stoppages in small lines and services. Bayliss
curve is the simplest determination of stability. The Langelier saturation index is
also used.
What/how are above ground tanks and piping Corrosion protection for above ground tanks and piping is prevented by:
protected from corrosion? cathodic protection, use if protective linings/coatings, eliminating different
types of metals in the distribution system, and treating the water with chemicals
to make it less corrosive
How do you tests fir alkalinity? The two tritiation methods of analysis are a standard acid to titrate a sample.
The end point of the titration is determined by the following: an indicator that
changes color at a certain pH, or potentiometric titration to end - point pH.
Using either of the methods, a measured amount of sample is titrated with a
standard sulfuric acid to a predetermined pH. Nomograph are a graphical form
of determining alkalinity. If the pH, total alkalinity, temperature and total
dissolved solids are known, any or all of the alkalinity forms may be estimated.
What is Turbidity? Turbidity can be described as a measure of the relative clarity of water.
Turbidity is an expression of the optical property that causes light to be
scattered and absorbed rather than transmitted in straight lines through the
sample.
What causes Turbidity? Turbidity is caused by clay, slit, finely divided organic and inorganic material.
Other suspended matter and microscopic organisms can also cause turbidity.
There is one approved method for running turbidity - the Nephelometric
Method (NTU)
What is chlorine Demand? The amount of chlorine used up to completely react with the water and its
suspended or dissolve material
, TCEQ Class B Surface Water B Test Material | Water Operator Certification Exam Prep
What is chlorine residual? When all the demand of the water is met any additional chlorine produces a
chlorine residual
What is chlorine dosage? Demand plus residual is the chlorine dosage. Chlorine Dosage = Demand +
Residual
What determines rate of disinfection? Chlorine concentration and contact time determines the rate and degree of
disinfection. If concentration increases, the time can be reduced; if
concentration is reduced the time must be increased.
How does temperature effect chlorine effectiveness? Chlorine effectiveness is greater at higher temperatures, up to the point that
chlorine volatizes. At low temperature, chlorine is more stable, but disinfection
time increases.
Is removing turbidity important for disinfection? Turbidity must be removed to low levels by sedimentation and filtration to
allow chlorine to contact pathogens.
What happens to dissolved solids on contact with Dissolved solids are oxidized on contact further reinforcing the importance of
chlorine? contact time.
No residual is formed until reducing agents are Manganese, iron, turbidity, organic matter, ammonia, or nitrates
destroyed. What are examples of reducing agents?
What the 4 stages of the Chlorine Demand Curve Stage 1: No residual is formed because inorganic demand destroys the
chart? chlorine. (Flat Line)
Stage 2: Monochloramines are formed as chlorine combines with organics
containing ammonia (rising curve). The chlorine to ammonia weight ratio at this
point is 5:1. Combined and total residual increases, chloro-organics are formed.
Stage 3: Increasing chlorine dosage (failing curve) to a chlorine/ammonia
weight ratio of 7.6:1 destroys chloramines and chloro-organics. Combined
decreases and free chlorine increases.
Stage 4: Enough chlorine is added to reduce all demand. The combined
residual remains the same, but free residual increases with dosage. This stage is
called "breakpoint" chlorination. The chlorine to ammonia ratio of 10:1 satisfies
all demand and disinfects the distribution system. ( second rising curve)
What is the difference between free chlorine and Free chlorine is more powerful than combined chlorine, but combined chlorine
combined chlorine (chloramines/chlorine-ammonia) lasts longer.
systems?
- combined chlorine requires a 60-minute detention time while free chlorine
requires 10 minutes.
-If combined residual is replaced by a free residual, less taste and odor in the
water usuals occurs.
- if combined residual is used : ph and temperature must be monitored closely
and the residual adjusted accordingly. For example, as the temperature
decreases the combines residual must be increased. Free residual does not
require such monitoring in the 6.0 - 8.0 pH range. Free chlorine residual
concentration is not affected by temperature changes.
, TCEQ Class B Surface Water B Test Material | Water Operator Certification Exam Prep
What is the minimum chlorine residual at the far reaches Free chlorine residual = .2mg/L
of the system for both free and combined?
Chloramine (combined) residual = .5 mg/L
- Surface water systems should not exceed a maximum free chlorine or
chloramine residual of 4 mg/L as a running average. Limiting residuals reduces
disinfection byproducts such as trihalomethanes and haloacetic acids. These
byproducts, consumed over a long period of time, may cause cancer.
What are the proper techniques for chlorine cylinder - secure the ton cylinders in a horizontal position and move with a lifting bar
storage? and hoist. Never roll them
- 150lbs cylinders shall be chained to rigid support and keep capped unless in
use.
- Check all chlorine systems for leaks before putting into service with a 10%
ammonia solution. Household ammonia is not approved. When ammonia
contacts chlorine gas white smoke results.
What are the steps to do before entering a room with a 1: notify other operators and have standby help for possible notification of
chlorine leak? emergency personnel
2: Be trained in emergency procedures and have knowledge of chlorinators,
tools, and ammonia use.
3: Put on a self-contained breathing apparatus (SCBA)
4: wear a safety harness and lifeline
What is the maximum withdrawal rate for 150lbs The maximum sustained gas withdrawal rate for 150lbs cylinders (vacuum
chlorine cylinders? transmission) is 1lbs per day per degree F.
The equivalent rate for ton cylinders (vacuum transmission) is 8 lb per day per
degree F.
Pressure transmission rates are 42 lbs per day for 140lb cylinders and 336 lb
per day for ton containers, based on an air temp of 70 degrees F.
What are chlorine cylinders equipped with to Chlorine cylinders are equipped with a fusible plug designed to melt between
help/prevent gas leaks in extreme temperatures? 158 and 165 f
Is chlorine the most cost effective and best disinfectant Yes
product?
Chlorine is available is what three forms? Gas - 100%
Solution - 5.25 to 15% chlorine (bleach)
Granular (solids) - 65 chlorine (calcium hypochlorite)
Explain and expand on Chlorine Dioxide (what it reacts Chlorine Dioxide is a gas used in small quantities to disinfect water. It does not
with, oxidizes, etc) react with organics to form THMs and HAAs. It oxidizes phenols, manganese,
iron, sulfurous and organic compounds which aids in the removal of tastes and
odors. It is a very effective bactericide and a superior virocide. It dies not
combine with ammonia. Chlorine Dioxide MRDL is .8 mg/L and monitoring
procedures are the same as for chlorine. The Chlorite MCL is .q mg/L and must
be monitored daily.
What is texas drinking water pH requirements? The texas drinking water requirements require a pH > 7.0 for the water
treatment plant finished water. EPA requires that pH analysis be preformed
within 15 minutes of the sample being caught.
How does pH affect Chlorine activity? When chlorine is added to water it forms hypochlorous acid (HOCL) and
hydrochloric acid (OCL). The hypochlorous acid is the effective disinfectant. At
a pH of 4.0 there is 100% hypochlorous acid. At a pH of 11 there is 100%
hypochlorite ion. At a pH of 7, the hypochlorous acid is at about 80% and the
hypochlorite ion makes up about 20% of the chlorine content. The lower the
pH is more effective chlorine is because you have more hypochlorous acid.
What is meant by water stability? Stable water is defined as water that will neither deposit or dissolve a calcium
carbonate film or scale. Since no water is stable indefinitely, chemical treatment
of water usually is intended to produce water that is slightly scale forming
without being liable to cause stoppages in small lines and services. Bayliss
curve is the simplest determination of stability. The Langelier saturation index is
also used.
What/how are above ground tanks and piping Corrosion protection for above ground tanks and piping is prevented by:
protected from corrosion? cathodic protection, use if protective linings/coatings, eliminating different
types of metals in the distribution system, and treating the water with chemicals
to make it less corrosive
How do you tests fir alkalinity? The two tritiation methods of analysis are a standard acid to titrate a sample.
The end point of the titration is determined by the following: an indicator that
changes color at a certain pH, or potentiometric titration to end - point pH.
Using either of the methods, a measured amount of sample is titrated with a
standard sulfuric acid to a predetermined pH. Nomograph are a graphical form
of determining alkalinity. If the pH, total alkalinity, temperature and total
dissolved solids are known, any or all of the alkalinity forms may be estimated.
What is Turbidity? Turbidity can be described as a measure of the relative clarity of water.
Turbidity is an expression of the optical property that causes light to be
scattered and absorbed rather than transmitted in straight lines through the
sample.
What causes Turbidity? Turbidity is caused by clay, slit, finely divided organic and inorganic material.
Other suspended matter and microscopic organisms can also cause turbidity.
There is one approved method for running turbidity - the Nephelometric
Method (NTU)
What is chlorine Demand? The amount of chlorine used up to completely react with the water and its
suspended or dissolve material
, TCEQ Class B Surface Water B Test Material | Water Operator Certification Exam Prep
What is chlorine residual? When all the demand of the water is met any additional chlorine produces a
chlorine residual
What is chlorine dosage? Demand plus residual is the chlorine dosage. Chlorine Dosage = Demand +
Residual
What determines rate of disinfection? Chlorine concentration and contact time determines the rate and degree of
disinfection. If concentration increases, the time can be reduced; if
concentration is reduced the time must be increased.
How does temperature effect chlorine effectiveness? Chlorine effectiveness is greater at higher temperatures, up to the point that
chlorine volatizes. At low temperature, chlorine is more stable, but disinfection
time increases.
Is removing turbidity important for disinfection? Turbidity must be removed to low levels by sedimentation and filtration to
allow chlorine to contact pathogens.
What happens to dissolved solids on contact with Dissolved solids are oxidized on contact further reinforcing the importance of
chlorine? contact time.
No residual is formed until reducing agents are Manganese, iron, turbidity, organic matter, ammonia, or nitrates
destroyed. What are examples of reducing agents?
What the 4 stages of the Chlorine Demand Curve Stage 1: No residual is formed because inorganic demand destroys the
chart? chlorine. (Flat Line)
Stage 2: Monochloramines are formed as chlorine combines with organics
containing ammonia (rising curve). The chlorine to ammonia weight ratio at this
point is 5:1. Combined and total residual increases, chloro-organics are formed.
Stage 3: Increasing chlorine dosage (failing curve) to a chlorine/ammonia
weight ratio of 7.6:1 destroys chloramines and chloro-organics. Combined
decreases and free chlorine increases.
Stage 4: Enough chlorine is added to reduce all demand. The combined
residual remains the same, but free residual increases with dosage. This stage is
called "breakpoint" chlorination. The chlorine to ammonia ratio of 10:1 satisfies
all demand and disinfects the distribution system. ( second rising curve)
What is the difference between free chlorine and Free chlorine is more powerful than combined chlorine, but combined chlorine
combined chlorine (chloramines/chlorine-ammonia) lasts longer.
systems?
- combined chlorine requires a 60-minute detention time while free chlorine
requires 10 minutes.
-If combined residual is replaced by a free residual, less taste and odor in the
water usuals occurs.
- if combined residual is used : ph and temperature must be monitored closely
and the residual adjusted accordingly. For example, as the temperature
decreases the combines residual must be increased. Free residual does not
require such monitoring in the 6.0 - 8.0 pH range. Free chlorine residual
concentration is not affected by temperature changes.
, TCEQ Class B Surface Water B Test Material | Water Operator Certification Exam Prep
What is the minimum chlorine residual at the far reaches Free chlorine residual = .2mg/L
of the system for both free and combined?
Chloramine (combined) residual = .5 mg/L
- Surface water systems should not exceed a maximum free chlorine or
chloramine residual of 4 mg/L as a running average. Limiting residuals reduces
disinfection byproducts such as trihalomethanes and haloacetic acids. These
byproducts, consumed over a long period of time, may cause cancer.
What are the proper techniques for chlorine cylinder - secure the ton cylinders in a horizontal position and move with a lifting bar
storage? and hoist. Never roll them
- 150lbs cylinders shall be chained to rigid support and keep capped unless in
use.
- Check all chlorine systems for leaks before putting into service with a 10%
ammonia solution. Household ammonia is not approved. When ammonia
contacts chlorine gas white smoke results.
What are the steps to do before entering a room with a 1: notify other operators and have standby help for possible notification of
chlorine leak? emergency personnel
2: Be trained in emergency procedures and have knowledge of chlorinators,
tools, and ammonia use.
3: Put on a self-contained breathing apparatus (SCBA)
4: wear a safety harness and lifeline
What is the maximum withdrawal rate for 150lbs The maximum sustained gas withdrawal rate for 150lbs cylinders (vacuum
chlorine cylinders? transmission) is 1lbs per day per degree F.
The equivalent rate for ton cylinders (vacuum transmission) is 8 lb per day per
degree F.
Pressure transmission rates are 42 lbs per day for 140lb cylinders and 336 lb
per day for ton containers, based on an air temp of 70 degrees F.
What are chlorine cylinders equipped with to Chlorine cylinders are equipped with a fusible plug designed to melt between
help/prevent gas leaks in extreme temperatures? 158 and 165 f
Is chlorine the most cost effective and best disinfectant Yes
product?
Chlorine is available is what three forms? Gas - 100%
Solution - 5.25 to 15% chlorine (bleach)
Granular (solids) - 65 chlorine (calcium hypochlorite)
