Water Treatment Practice Exam #2
How many stages are in a breakpoint chlorination curve?
4
Under the Surface Water Treatment Rule, what must the reduction of viruses be through filtration and disinfection?
99.99%
What are the two types of aquifers?
Confined and unconfined.
What is adsorption?
Constituents sticking to the surface of a substance
What is the purpose of a packing in a pump?
Control the leakege of water along the pump shaft and prevent air from entering along the shaft when the pump is in a suction lift condition.
Which type of filtration process is approved by the Surface Water Treatment Rule?
Conventional water treatment.
What is the problem with very soft water?
Corrosion
Which of the following is not a type of a coliform test?
DPD
What is a pathogen?
Disease-causing microorganisms.
Where would you most likely see high levels of nitrate in the groundwater supply?
Near agricultural land
What is a typical characteristic of a colloidal particle in raw water?
Negative charge on the surface
What is the reason for adding coagulants at the flash mixer?
Neutralize negative charge on colloids.
Which of the following is true about fusible plugs on a chlorine container?
Never remove it.
Which contaminant causes Blue Baby Syndrome?
Nitrate.
What is the amount of water that can be withdrawn tion an aquifer whitout significant environmental impact?
Safe yield.
Why would a water purveyor switch from chlorine gas to sodium hypochlorite?
Safety
Which of the following is a grab sample?
Sample taken on a one time basis without consideration of flow or time.
What information should be identified on the sampling container?
Sampling location, date, and time.
What is a common problem associated with hardness i water?
Scaling.
What is an example of a non-community, non-transient water
School.
In wich part of the water treatment plant are 99% of the suspended solids removed?
Sedimentation and filtration.
What is a short circuiting in a clarifer?
Shorter settling time in basin.
How is the rate of head loss affected by a more uniform filter media?
Slower
What is rhe purpose of flocculation?
Slowly stir water to bring smaller flocks together to form larger ones.
Which of the following is not true about the Total Coliform Rule?
Smaller systems that collect fewer than 40 samples cannot have coliform positive results inn more than 2 samples per month.
Which chemical is used to raise the pH in water?
Soda ash
Which of the following is not a example of a suspended solid?
Soluble calcium
What might happend if insufficient amount of coagulants were injected into the flash mixer?
Some colloids may repeal each other.
Which entity is responsible for enforcing the drinking water standards?
State
What is the impact of algae to water quality?
Taste and odor problems.
What is the most common water quality complain from costumers?
Taste and odor problems.
What is free chlorine?
The concentration of residual chlorine in water which is present as dissolved gas (CL2), hypochlorous acid (HOCI), and/or hypochlorite ion (OCI).
What is the concentration of chlorine gas?
100%.
Which of the following is true about soluble iron and manganese?
Colorless.
What are the 4 zones in a clarifier?
Inlet, Outlet, Settling, Sludge.
Which of the following is the correct order of treatment for a conventional water treatment plant?
Intake, Coagulation, Flocculation, Sedimentation, Filtration, Disinfection.
When is Brillant Green Bile used to test for coliform?
Multiple Tube Fermentation method.
Which of the following range of pH is considered to be acidic?
0-6
What is a thermocline?
A thin but distinct layer in a reservoir in which temperature changes more rapidly with depth than it does in the layers above or below.
How does PAC remove contaminants feom the water?
Adsorption.
Which of the following is not part of the Surface Water Treatment Rule?
All water systems are allowed to ise disinfection only for surface water sources that meet criteria for water quality and watershed protection.
pH will increaseif the following chemical is added to water.
Ammonia.
What is a sanitary survey?
An analisis to determine all potencial water quality impacts to a proposed well.
What impact doea precipitated manganese have on water?
Blackish water
What is the purpose of surface washing in a filtration unit?
Break-up mudballs.
What is one of the causes of hardness in water?
Calcium.
What is the health effect of consuming water with high levels of lead?
Cardiovascular effects, increased blood pressure and incidence of hypertension.
What is the likely cause of a pinping noise in a pump?
Cavitation
What is formed when free chlorine reacts with ammonia?
Chloramine.
Which of the following will most likely lead to be the lowest concentration of THMs in treated water?o
Chloramines.
Chlorine demands is best describe as which of the following?
Chlorine dosage - chlorine residual.
Which of the following categories does bacterial belong to?
Colloidal
What can be done to minimize the formation of THM?
Eliminate or reduce chlorination before the filters.
What is the term used to describe the upper layer of a stratified reservior?
Epilimnion
What is an example of natual organic matter?
Fallen leaves
What is the source of fecal coliform bacteria?
Feces.
What is considered to be a quick remedy to adress a sudden increase in filtered water turbidity?
Feed a filter-aid chemical to the filter influent.
What is the standard requirement for conventional and direct filtration?
Filtered water must be less than or equal to 0.3 NTU in 95% of monthly measurements.
Which of the following controls the efficiency of removing suspended solids in the sedimentation process?
Flowrate
Why is it harmful to backwash at high velocity?
Flushes some media into the spend backwash water.
What is the main drawback of using sodium hypochlorite to disinfect water?
Formation of THMs.
What occurs on the right side of breakpoint chlorination curve?
Free available residual chlorine being to form.
What is a typical characteristic of chlorine gas?
Greenish yellow color
Which of the following Will least likely impact the formation of flocs during the coagulation and flocculation process?
Hardness.
What would cause a filter to being backwashing?
Head loss
What happens over the course of a filter run time?
Headloss increases.
What is the drawback of using UV for disinfection?
High energy cost.
Which of the following is not used to mix coagulants?
Horizontal paddle wheel.
Why is coliform used as a indicator organism?
It reduce the complexity and cost of analysis.
What is used to evaluate new coagulants or polymers being considered for use at the plant?
Jar Test.
Coliform is most likely to be found in which of the following water supply?
Lake.
What does the addition of carbon dioxide do to the pH of water?
Lowers it.
What is another name for the Multiple Tube Fermentation test?
MPN
Which of the following is not considered free residual chlorine?
Monochloramine
Which of the following is not true about the Total Coliform Rule?
Monthly sampling requirements are not based on population served.
What agency protects the health and safety of industrial employees?
OSHA
What is an unconfined aquifer?
One in which groundwater posseses a free surface open to the atmosphere.
Which of the following impacts the color of source water?
Organics, such as soil and leaves.
Which of the following is an unstable form of disinfection?
Ozonation.
What is an imaginary surface to which ground water rises under hydrostatic pressure in Wells or springs?
Piezometric surface
What is the first priority in water treatment?
Production of safe drinking water.
What is the definition of a public water system?
Public or privately owned water system that has at least 15 service connections, or regularly serves an average of at least 25 people daily at least 60 days per year.
Which pathogen is smallest in size?
Virus.
What is static water level in a well?
Water level when pump is not running.
When is direct filtration used instead of conventional water treatment?
When source water is low in turbidity, color, and coliform.