Plumbing School Year 3 Module 3
The contact time is determined by several factors:
--The type and amount of contamination in the system --The concentration of chlorine used --The pH level of the water --The temperature of the water
A water conditioner should be installed if the iron content tests higher than
0.2 ppm
Staining of plumbing fixtures may be caused by iron concentration as low as
0.3 ppm
Treat the water supply system if testing reveals sulfur content greater than
1 ppm
Water should be treated if its turbidity is greater than
10 ppm
The approximate amount of water that a gallon of bleach at a solution of 1 parts per million can disinfect is
10,000 gallons
A gallon of chlorine bleach at a solution of only 1 ppm will treat about
10,000 gallons of water
While chlorination will kill bacteria with an exposure of 30 minutes, the pasteurization process uses heated water to kill harmful organisms in as little as
15 seconds
Untreated water passes through a heat exchanger, where it is heated to about
150 degrees Farenheit
A pump draws the water into an electric heating chamber. There, the temperature of the water is raised to
161 degrees F for at least 15 seconds
In a pasteurization system, in order to kill organisms in the water, the electric heating chamber raises the temperature of the water to
161 degrees F for at least 15 seconds
The amount of hardness in one grain is
17.1 ppm
Commercial laundry bleach has
19 percent sodium hypochlorite
Most residential pasteurized systems disinfect water at a slow hourly rate typically
20-24 gallons per hour
If using a solution of at least 50 parts per million of chlorine, you let the system stand for
24 hours
When disinfecting a water supply system once the system has been completely installed, a solution of at least 200 ppm of chlorine can be used if the system is allowed to stand for
3 hours
Calcium hypochlorite is available in power and tablet form and contains anywhere from
30 percent to 75 percent chlorine
One gallon of domestic laundry bleach has a sodium hypochlorite content of
5.25 percent
A gallon of domestic laundry bleach contains
5.25 percent sodium hypochlorite
A gallon of chlorine bleach at a solution of 5 ppm will treat about
50,000 gallons of water
The percentage of impurities removed from water by distillation systems
99%
Oxidizing agent
A chemical that is used for oxidation and is made up largely of oxygen
Alum
A chemical used for coagulation. It consists of aluminum and sulfur
Chlorinator
A device that distributes chlorine in a water supply system
K value
A mathematical variable used to determine contact time based on the highest pH level and lowest temperature of the water in a water supply system
Grains per gallon
A measure of the hardness of water. One grain equals 17.1 ppm of hardness
Turbidity unit
A measurement of the percentage of light that can pass through a sample of water
Precipitate
A particle created by coagulation that settles out of the water.
Ion exchange
A technique used in water softeners to remove hardness by neutralizing the electrical charge of the mineral atoms.
Adsorption
A type of absorption that happens only on the surface of an object
Point-of-use (POU) unit
A water conditioner that is located at an individual fixture
Point-of-entry (POE) unit
A water conditioner that is located near the entry point of a water supply
Ion
An atom with a positive or negative electrical charge
Solenoid valve
An electronically operated plunger used to divert the flow of water in a water conditioner.
Contamination
An impairment of potable water quality that creates a hazard to public health
Pollution
An impairment of the potable water quality that does not create a hazard to public health but affects the water's taste and appearance
Floc
Another term for precipitate
____________________ removes iron and sulfur from water
Chlorine
Water conditioner
Device used to remove harmful organisms and materials from water.
Pasteurization
Heating water to kill harmful organisms in it.
When calculating the contact time for chlorinating a water system to disinfect it, a plumber must determine the system's
K value
Time=
K value/concentration in ppm
Diatomaceous earth
Soil consisting of the microscopic skeletons of plants that are all locked together
Contact time
The amount of time that a chlorine solution must remain in a water supply system in order to disinfect it, as determined by the type and amount of contamination in the system, the concentration of chlorine used, the pH (acidity or alkalinity) level of the water, and the temperature of the water.
Coagulation
The bonding that occurs between contaminants in the water and chemicals introduced to eliminate them.
Backwashing
The cleaning process of a fully automatic water softener
Disinfection
The destruction of harmful organisms in water
Sodium hypochlorite
The liquid form of chlorine, commonly found in laundry bleach
Precipitation
The process of removing contaminants from water by coagulation.
Distillation
The process of removing impurities from water by boiling the water into steam
Calcium hypochlorite
The solid form of chlorine. It comes in powder and tablet form.
Osmosis
The unequal back-and-forth flow of two different solutions as they seek equilibrium.
Chlorination
The use of chlorine to disinfect water
True/False: Calcium hypochlorite may form deposits in pipes.
True
True/False: If a system has iron-or sulfur-rich water, monitor and adjust the system's chlorine use regularly. High levels of alkaline in the water may slow the disinfection process. Cold water will also slow the disinfection process.
True
True/False: Soft water contains sodium chloride. Softened water may pose a health risk to people on strict low-sodium diets.
True
Ultraviolet light
Type of disinfection in which a special lamp heats water as it flows through a chamber
Turbidity in water is commonly treated by using
a diatomaceous earth filter
If the pH of a water sample is 7 or below, the water supply system should be treated for
acidity
Public water utilities use lime in treatment process to remove
acidity
An example of a highly effective adsorbent material is
activated carbon
Most objectionable water tastes and odors, other than metallic flavors and saltiness, can be eliminated by using an
activated carbon filter
Codes require that reverse-osmosis systems drain into the waste system through an
air gap
Fine solid particles can be precipitated out of water by adding
alum
Water contaminated with iron and sulfur is often referred to as
black water
At the end of each workday, all installed pipes should be
capped
Install ___________________________ to remove any residual chlorine taste from the water.
charcoal filters
In a precipitation system, the action of chemicals bonding with contaminants in the water is called
coagulation
In an ultraviolet-light system, the lamp's efficiency will be reduced by
cold water
A commonly used filter in municipal water treatment systems is
diatomaceous earth
Once a water softener is completed, the unit must be
disinfected
In situations where the water supply is from a private well, plumbers must install
disinfection devices
The principle of osmosis is that solutions tend to seek
equilibrium
The process of scouring water to remove particles and chemicals is called
filtration
Water hardness is measured in
grains per gallon
Acidity in the water can react with copper pipes that are
green
Water that contains a high percentage of minerals is called
hard water
Calcium and magnesium salts in water are the cause of
hardness
Distillation systems are effective at eliminating
hardness
After a newly installed water supply system has been flushed and disinfected, water samples should be taken and laboratory-tested for
harmful bacteria
Scale occurs when the chemical structure of calcium, magnesium, or sodium atoms is changed by
heat
An unpleasant smell from water is often due to the presence of
hydrogen sulfide
To treat a salty flavor in the water, the usual method is to
install a reverse osmosis system
A red slippery jelly formed on the side of a toilet tank is caused by
iron-eating bacteria
Iron test kits can also be used to detect
manganese
Calcium carbonate is often used to trap acid in a
neutralizing filter
An activated carbon filter will remove
organic chemicals
In addition to disinfectant properties, chlorine will
remove iron and sulfur
To give coagulants time to work, precipitation systems usually include a
retention tank
Water under high pressure is forced through a membrane in
reverse osmosis systems
In an oxidizing filter, magnesium is used to convert iron in the water into
rust
Mineral salts dissolve in water form a coating inside pipes
scale
Water hardness can be determined by using a
soap solution
Resin pellets in an ion-exchange system are saturated with
sodium
Without clean water,
the quality and span of life are drastically reduced
The two tanks in a typical residential ion-exchange system are
the resin tank and the brine tank
To allow the ultraviolet lamp to reach full intensity before water is admitted to the disinfecting chamber, units are equipped with a
time-delay switch
After pasteurization, the treated water is sent
to a pressure tank
The purpose of the quartz sleeve in UV systems is
to prevent water in the disinfecting chamber from cooling the lamp
The heating coils of a home distillation unit should be cleaned periodically with
vinegar