TCEQ-Class-B-Surface-Water-B-test-material--Exam-with-
Questions-and-Correct-Answers
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-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
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.-
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-
Questions-and-Correct-Answers
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-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
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.-
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-
