B test material - TCEQ Class B Surface Water
What is the most important factor affecting the useful life of service lines? - correct answer It is
the ability of the material to resist internal and external corrosion
When does Suction Head exist? - correct answer Suction head exists when the source of supply
is above the centerline of the pump.
What is Net positive Suction Head (NPSH) - correct answer NPSH is the pressure under which
water enters the eye of the impeller in a centrifugal pump. Insufficient NPSH is the main cause
of pump cavitation
Explain and expand on Chlorine Dioxide (what it reacts with, oxidizes, etc) - correct answer
Chlorine Dioxide is a gas used in small quantities to disinfect water. It does not 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? - correct answer 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? - correct answer 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? - correct answer 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
,B test material - TCEQ Class B Surface Water
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 protected from corrosion? - correct answer
Corrosion protection for above ground tanks and piping is prevented by: 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? - correct answer 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? - correct answer 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? - correct answer 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? - correct answer The amount of chlorine used up to completely react
with the water and its suspended or dissolve material
What is chlorine residual? - correct answer When all the demand of the water is met any
additional chlorine produces a chlorine residual
,B test material - TCEQ Class B Surface Water
What is chlorine dosage? - correct answer Demand plus residual is the chlorine dosage. Chlorine
Dosage = Demand + Residual
What determines rate of disinfection? - correct answer 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? - correct answer 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? - correct answer 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 chlorine? - correct answer Dissolved solids are
oxidized on contact further reinforcing the importance of contact time.
No residual is formed until reducing agents are destroyed. What are examples of reducing
agents? - correct answer Manganese, iron, turbidity, organic matter, ammonia, or nitrates
What the 4 stages of the Chlorine Demand Curve chart? - correct answer Stage 1: No residual is
formed because inorganic demand destroys the 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.
, B test material - TCEQ Class B Surface Water
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 combined chlorine (chloramines/chlorine-
ammonia) systems? - correct answer Free chlorine is more powerful than combined chlorine,
but combined chlorine lasts longer.
- 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.
What is the minimum chlorine residual at the far reaches of the system for both free and
combined? - correct answer Free chlorine residual = .2mg/L
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 storage? - correct answer - secure the ton
cylinders in a horizontal position and move with a lifting bar and hoist. Never roll them
- 150lbs cylinders shall be chained to rigid support and keep capped unless in use.
What is the most important factor affecting the useful life of service lines? - correct answer It is
the ability of the material to resist internal and external corrosion
When does Suction Head exist? - correct answer Suction head exists when the source of supply
is above the centerline of the pump.
What is Net positive Suction Head (NPSH) - correct answer NPSH is the pressure under which
water enters the eye of the impeller in a centrifugal pump. Insufficient NPSH is the main cause
of pump cavitation
Explain and expand on Chlorine Dioxide (what it reacts with, oxidizes, etc) - correct answer
Chlorine Dioxide is a gas used in small quantities to disinfect water. It does not 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? - correct answer 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? - correct answer 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? - correct answer 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
,B test material - TCEQ Class B Surface Water
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 protected from corrosion? - correct answer
Corrosion protection for above ground tanks and piping is prevented by: 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? - correct answer 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? - correct answer 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? - correct answer 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? - correct answer The amount of chlorine used up to completely react
with the water and its suspended or dissolve material
What is chlorine residual? - correct answer When all the demand of the water is met any
additional chlorine produces a chlorine residual
,B test material - TCEQ Class B Surface Water
What is chlorine dosage? - correct answer Demand plus residual is the chlorine dosage. Chlorine
Dosage = Demand + Residual
What determines rate of disinfection? - correct answer 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? - correct answer 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? - correct answer 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 chlorine? - correct answer Dissolved solids are
oxidized on contact further reinforcing the importance of contact time.
No residual is formed until reducing agents are destroyed. What are examples of reducing
agents? - correct answer Manganese, iron, turbidity, organic matter, ammonia, or nitrates
What the 4 stages of the Chlorine Demand Curve chart? - correct answer Stage 1: No residual is
formed because inorganic demand destroys the 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.
, B test material - TCEQ Class B Surface Water
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 combined chlorine (chloramines/chlorine-
ammonia) systems? - correct answer Free chlorine is more powerful than combined chlorine,
but combined chlorine lasts longer.
- 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.
What is the minimum chlorine residual at the far reaches of the system for both free and
combined? - correct answer Free chlorine residual = .2mg/L
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 storage? - correct answer - secure the ton
cylinders in a horizontal position and move with a lifting bar and hoist. Never roll them
- 150lbs cylinders shall be chained to rigid support and keep capped unless in use.
