Exam (elaborations)
AWWA Water Operator Certification Exam Prep Questions and Answers 2024
- Course
- Institution
AWWA Water Operator Certification Exam Prep
[Show more]
Content preview
AWWA Water Operator CertificationExam Prep
What is the most common disinfection by product when adding chlorine to water
containing natural and inorganic matter? - answer Chloroform
What will most probably cause taste and odors, slime, and filter clogging? - answer
Blue-green Algae
Why can rapid sand filters handle higher filtration rates compared to slow sand filters? -
answer Coarser sand
Iron bacteria can interfere with ___________ because the bacteria produce
_____________that prevents the stabilization chemicals from reaching the pipe surface.
- answer stabilization, a slime layer
Hypochlorous acid is favored over hypochlorite ion when the pH is _____________and
the temperature is ___________. - answer low, low
What filter has an unstratified media distribution? - answers low sand filters
What is (are) the combine chlorine residual(s) at pH values ranging from 6.5 to 8.5? -
answer Monochloramine and dichloramine
When iron alone is treated using manganese greensand filters, the chlorine feed rate
should be about _________________. - answer1.0 to 1.2 times the iron concentration
chlorination of water that has high concentrations of natural organic matter will produce
- answerTHMs
When disinfecting with chloramines, when can the ammonia be added to the process? -
answerBefore, same time as, or after the chlorine
What will settle out of the water in a short period of time? - answerVery fine silt
Point-of-use activated carbon filters are most effective for removing
_________________. - answerChlorine
Potassium permanganate is used as an oxidant for control of ____________________.
- answerIron and manganese, organic precursors, and taste and odors
,What must an operator periodically check regarding the cyclone separator system? -
answerStorage bin or hopper to empty of sand and grit
These types of chemicals chemically tie up scale-forming ions and are eventually
ingested by consumers. - answerSequestering agents
An operator should record filter ______________ measurements, condition, and depth
of media on a ________ basis. - answerbed expansion, quarterly
Lime will precipitate noncarbonate hardness from the water, but it also orms
noncarbonate salts that cause noncarbonate hardness. What are these salts? -
answerCaSO4 and CaCl2
What are absolute ratings based on with regard to membranes? - answerLargest pore
opening
How ar manganese greensand beds regenerated? - answerBackwashed with
permanganate solution
The most effective process for removing radon gas, when considering cost and
footprint, would be ____________. - answerpacked tower aeration
What is the primary advantage of placing a properly sized anthracite coal layer over
manganese greensand? - answerLonger filter run times
What factor will cause problems for chlorination? - answerForeign substances
In the lime-soda ash softening process, smaller plants find that ________ is less
expensive to purchase; regardless of the size of the plant, ___________ needs to be
mixed long enough because it dissolves rather slowly. - answercalcium hydroxide, lime
What does the optimal pH establish when applied to iron and manganese oxidation? -
answerDetention time
A water plant using chloramines as a disinfectant has allowed sizable amounts of
turbidity to enter the distribution system. If this occurs over a period of years, what will
occur at the far end of the distribution system? - answerTaste and odor will develop,
Bacterial growth will be supported, and Nitrification
The reduction of color would most likely occur after - answercoagulation, flocculation,
and sedimentation
To eliminate hydrogen sulfide (H2S), the pH of the water should be lowered to
____________ or less before beginning aeration. - answer6.0
Permanganate reactions are largely dependent on ___________. - answerpH
,What are the primary reasons that more small water stems are installing pressure
filters? - answerBecause installation and operating costs are low
Because lime slurries have a _________ and a ___________ in water, calcium
carbonate will ____________ on anything the slurry touches. - answerhigh pH, low
solubility, preciptate
It is recommended that the free chlorine residual at a customer's tap should be at least
________. - answer0.2 mg/L
Microfiltration is considered to be intermediate between ___________ based on pore
size. - answerultrafiltration and multimedia granular filtration
After microscreening, there should be a significant reduction in ______________. -
answerTurbidity
How can the problem of poorly formed floc be solved? - answerUse of coagulant aid
What chemical used in corrosion control gives off large quantities of CO2 when it comes
in contact with an acid? - answerSoda ash
Alum requires _____________ to be present naturally or added fro proper coagulation,
and about _____________ is required for each milligram of alum added per liter. -
answeralkalinity, 0.5 mg/L
A cloudy appearance in the last flocculation chamber is usually caused by
____________. - answerinadequate coagulant dosage
What type of meter is most commonly use for customer metering? - answerPositive-
displacement meters
In general, the size of floc that has been found to be optimal for settling efficiency is
____________________. - answerpinhead-size floc
In a pulsator clarifier, what is the purpose of the pulses and how often are pulses
generated? - answerTo maintain a uniform sludge layer; 40-50 sec
UV application will - answerinhibit bacterial growth and replication
Calcium hypochlorite used in water treatment disinfection ranges in percentage strength
of available chlorine from _______________. - answer65% to 70%
Manganese greensand filters remove iron and manganese by a combination of both
_________. - answerAdsorption and oxidation
, After water has been softened, it is close to pH 11; thus, it needs to be stabilized by a
process known as recarbonation. What small amount of hardness chemical is formed
and what is precipitated in the process? - answerCalcium bicarbonate, magnesium
carbonate
UV is used as a disinfectant because it is effective in the inactivation of _____ and
because it _______. - answerCryptosporidium, does not produce DBPs
A common problem with hypochlorinators is ____________. - answerbroken diaphragm
If algae or slime growth in sedimentation basins are a problem, drain the basin and
apply a solution of _______ per liter of water using a brush to remove the growth. -
answer10g of copper sulfate and 10 g of lime
What two major problems will improperly stabilized softened water cause? -
answerscale deposits or corrosive water
Coagulation and flocculation are _____ processes. - answerChemical and mechanical
The C x T value is calculated using most or part of the treatment plant, some distribution
piping and to the _______. - answerfirst customer
The most important reason to control corrosion and scaling in the distribution system is
to _______. - answerprotect public health
A bacterial slime layer prevents the deposition of _____, and when the slime
occasionally gets sloughed away, the slime carries away _______ and leaves the pipe
surface bare. - answercalcium carbonate, calcium carbonate
What is the major advantage of GAC over anthracite? - answerBetter adsorption of
organics
The success of the conventional treatment design is primarily due to the ___________
process. - answerCoagulation, sedimentation, filtration (All of the above)
How is hardness expressed in the ion exchange process? - answergrains/gal
Manganese will produce _______ water. - answerbrown or black
Air binding is caused by pressure in the filters __________ than atmospheric pressure,
and it can cause _______ flow. - answerlower, resistance to
What filter types would be best for direct filtration? - answermonomedium filters
What are the two broad classes of corrosion in water systems? - answerLocalized
corrosion and uniform corrosion
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller julianah420. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $18.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
72042 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now