T2 Prac 2 Flashcards
What is a pathogen?
Disease-causing microorganism
What is the impact of algae to water quality?
Taste and odor problems
What is the concentration of chlorine gas?
100%
What is not used to mix coagulants?
Horizontal paddle wheel
What is considered to be a quick remedy to address a sudden increase in filtered turbidity?
Feed a filter-aid chemical to the filter influent
What is the likely cause of a pinging noise in a pump?
Cavitation
What controls the efficiency of removing suspended solids in the sedimentation process?
Flowrate
What is a sanitary survey?
An analysis to determine all potential water quality impacts to a proposed well
What category does bacteria belong to?
Colloidal
Under the Surface Water Treatment Rule, what must the reduction of viruses be through filtration and disinfection?
99.99%
What is not considered free residual chlorine?
Monochloramine
Why is coliform used as an indicator organism?
It reduces the complexity and cost of analysis
What is an example of a non-community, non-transient water system?
School
What is the purpose of a packing in a pump?
Control the leakage of water along the pump shaft and prevent air from entering along the shaft when the pump is in a suction lift condition.
What does the addition of carbon dioxide do to the pH of water?
Lowers it
What is an unconfined aquifer?
One in which groundwater possess a free surface open to the atmosphere
What is the static water level in a well?
Water level when pump is not running
What would least likely impact the formation of flocs during the coagulation and flocculation process?
Hardness
What is formed when free chlorine reacts with ammonia?
Chloramine
Which contaminant causes Blue Baby Syndrome?
Nitrate
What is free chlorine?
The concentration of residual chlorine in water which is present as dissolved gas (Cl²), hypochlorous acid (HOCl), and/or hypochlorite ion (OCI-)
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.
What agency protects the health and safety of industrial employees?
OHSA
What is the first priority in water treatment?
Production of safe drinking water
What is the health effect of consuming water with high levels of lead?
Cardiovascular effects, increased blood pressure and incidence of hypertension
What is an imaginary surface to which groundwater rises under hydrostatic pressure in wells or springs?
Piezomectric surface
What is used to evaluate new coagulants or polymers being considered for use at the plant?
Jar test
What are the 4 zones of a clarifier?
Inlet, outlet, settling, sludge
Which types of filtration process is approved by the Surface Water Treatment Rule?
Conventional water treatment
What impacts the color of source water?
Organics, such as soil and leaves
Coliform is most likely to be found in which water supply?
Lake
What is the amount of water that can be withdrawn from an aquifer without significant environmental impact?
Safe yield
pH will increase with what chemical added to water?
Ammonia
What is an unstable form of disinfection?
Ozonation
How many stages are in a breakpoint chlorination curve?
4
Chlorine demand is best described as?
Chlorine dose - chlorine residual
What is an example of a natural organic matter?
Fallen leaves
What is a typical characteristic of colloidal particle in raw water?
Negative charge on the surface
What is short circuiting in a clarifier?
Shorter settling time in basin
What would cause a filter to begin backwashing?
Head loss
What is the purpose of surface washing in a filtration unit?
Break-up mudballs
Where would you most likely see high levels of nitrate in the groundwater supply?
Near agricultural land
What is adsorption?
Constituents sticking to the surface of a substance
In which part of the water treatment plant are 99% of the suspended solids removed?
Sedimentation and filtration
What will most likely lead to the lowest concentration of THMs in treated water?
Chloramines
What is not true about Total Coliform Rule?
Smaller systems that collect fewer than 40 samples can not have coliform positive results in more than 2 samples per month
What is true about fusible plugs on a chlorine container?
Never remove it
What is the most common water quality complaint from customers?
Taste and odor problems
What information should be identified on the sampling container?
Sampling location, date, and time
What is the standard requirement for conventional and direct filtration?
Filtered water must be less than or equal to .3 NTU in 95% of monthly measurements
What is the main drawback of using sodium hypochlorite to disinfect water?
Formation of THMs
What is one the causes of hardness in water?
Calcium
Which chemical is used to raise the pH in water?
Soda ash
What is the purpose of flocculation?
Slowly stir water to bring smaller flocs together to form larger ones
What range of pH is considered to be acidic?
0-6
What is the term used to describe the upper layer of a stratified reservoir?
Epilmnion
What is another name for the Multiple Tube Fermentation Test?
MPN
What impact does precipitated manganese have on water?
Blackish water
What is not part of the Surface Water Treatment Rule?
All water systems are allowed to use disinfection only for surface water sources that meet criteria for water quality and watershed protection
What is a typical characteristic of chlorine gas?
Greenish yellow color
What is not true about the Total Coliform Rule?
Monthly sampling requirements are not based on population served
What can be done to minimize the formation of THM?
Eliminate or reduce chlorination before the filters
What is the source of fecal coliform bacteria?
Feces
What is the drawback of using UV for disinfection?
High energy cost
What are two types of aquifers?
Confined and unconfined
What is a common problem associated with hardness in water?
Scaling
What is the problem with very soft water?
Corrosion
Why is it harmful to backwash at a high velocity?
Flushes some media into spent backwash water
What occurs on the right side of the breakpoint chlorination curve?
Free available residual chlorine begin to form
How does PAC remove contaminants from the water?
Adsorption
Which entity is responsible for enforcing the drinking water standards?
State
How is the rate of head loss affected by a more uniform filter media?
Slower
What is true about soluble iron and manganese?
Colorless
What is the reason for adding coagulants at the flash mixer?
Neutralize negative charge on colloids
Why would a water purveyor switch from chlorine gas to sodium hypochlorite?
Safety
Which pathogen is smallest in size?
Virus
What is not an example of a suspended solid?
Soluble calcium
What is not a type of a coliform test?
DPD
Definition of a public water system
Publicly 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
When is Brilliant Green Bile used to test for coliform?
Multiple Tube Fermentation method
What is the correct order of treatment for a conventional water treatment plant?
Intake, Coagulation, Flocculation, Sedimentation, Filtration, Disinfection
What might happen if insufficient amount of coagulants were injected into the flash mixer?
Some colloids may repel each other
What is a grab sample?
Sample taken on a one time basis without consideration of flow or time
What happens over the course of a filter run time?
Headloss increases
When is direct filtration used instead of conventional water treatment?
When source water is low in turbidity, color, and coliform
