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.
,B TEST MATERIAL - TCEQ CLASS B SURFACE WATER EXAM QUESTIONS
AND ANSWERS UPDATED 2024/2025 ALL ANSWERS CORRECT
VERIFIED TO SCORE A+
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.
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)
,B TEST MATERIAL - TCEQ CLASS B SURFACE WATER EXAM QUESTIONS
AND ANSWERS UPDATED 2024/2025 ALL ANSWERS CORRECT
VERIFIED TO SCORE A+
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
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.
, B TEST MATERIAL - TCEQ CLASS B SURFACE WATER EXAM QUESTIONS
AND ANSWERS UPDATED 2024/2025 ALL ANSWERS CORRECT
VERIFIED TO SCORE A+
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)
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.
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