B TEST MATERIAL - TCEQ CLASS B SURFACE WATER EXAM QUESTIONS
AND ANSWERS UPDATED 2024/2025 ALL ANSWERS CORRECT
VERIFIED TO SCORE A+
What is the most important factor affecting the useful life of service lines? - CORRECT
ANSWERS It is the ability of the material to resist internal and external corrosion
When does Suction Head exist? - CORRECT ANSWERS Suction head exists when the
source of supply is above the centerline of the pump.
What is Net positive Suction Head (NPSH) - CORRECT ANSWERS 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
ANSWERS 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 ANSWERS 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 ANSWERS 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 ANSWERS 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.
,B TEST MATERIAL - TCEQ CLASS B SURFACE WATER EXAM QUESTIONS
AND ANSWERS UPDATED 2024/2025 ALL ANSWERS CORRECT
VERIFIED TO SCORE A+
What/how are above ground tanks and piping protected from corrosion? - CORRECT
ANSWERS 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 ANSWERS 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 ANSWERS 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 ANSWERS 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 ANSWERS The amount of chlorine used up to
completely react with the water and its suspended or dissolve material
What is chlorine residual? - CORRECT ANSWERS When all the demand of the water is
met any additional chlorine produces a chlorine residual
What is chlorine dosage? - CORRECT ANSWERS Demand plus residual is the chlorine
dosage. Chlorine Dosage = Demand + Residual
,B TEST MATERIAL - TCEQ CLASS B SURFACE WATER EXAM QUESTIONS
AND ANSWERS UPDATED 2024/2025 ALL ANSWERS CORRECT
VERIFIED TO SCORE A+
What determines rate of disinfection? - CORRECT ANSWERS 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 ANSWERS 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 ANSWERS 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 ANSWERS
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 ANSWERS Manganese, iron, turbidity, organic matter,
ammonia, or nitrates
What the 4 stages of the Chlorine Demand Curve chart? - CORRECT ANSWERS 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.
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)
, B TEST MATERIAL - TCEQ CLASS B SURFACE WATER EXAM QUESTIONS
AND ANSWERS UPDATED 2024/2025 ALL ANSWERS CORRECT
VERIFIED TO SCORE A+
What is the difference between free chlorine and combined chlorine
(chloramines/chlorine-ammonia) systems? - CORRECT ANSWERS 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 ANSWERS 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 ANSWERS -
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.
- 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.
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