Water Flashcards
Humans consume an average of __ to __ lbs of water per day
3 to 5 lbs per day
The ocean contains nearly ______ % of all our water
97%
The _____ powers the hydrological cycle
sun
What is thermal stratification
the change in temperature of water at different depths in a body of water. it occurs because colder water is more dense.
name the three sections of thermal stratification from top to bottom
epilimnion -upper layer
thermocline
hypolimnion - lower layer
in winter what layers exist in thermal stratification?
ice exists above the water layer
name the three ages of lakes
oligotrophic - young
mesotrophic - middle
eutrophic - old or mature lake
a lake is considered “dead” when it has been depleted of _________
oxygen
why are plants important to a lake?
because they provide oxygen
What is eutrophication
a lake condition of algal blooms due to over enrichment of nutrients such as phosphates and nitrates.
can be natural or manmade
if left untreated manmade eutrophication can result in a ______ lake because the algae depletes the ______
dead
oxygen
What chemical can be used to control algae
copper sulfate CuSO4 can be used but in limited concentrations so it doesn’t kill fish and other aquatic life
what two chemicals can be used to prevent evaporation from lakes
hexadecanol and octadecanol
they are non toxic
so why don’t we convert ocean water into drinking water?
because it’s too costly due to the high salinity and minerals in the water
what are some types of surface waters
spring
pond
swamp
stream
what is an aquifer?
an underground layer of water with permeable rock or other materials through which a well can be drilled
what is the water table
the area of the start of the zone of saturation
What three things should be considered in the construction of the well
expensive
depth of water table
type of construction
why do higher water tables have less potable water?
because the water did not have enough time to naturally filtrate through the soil
What are the 3 types of wells
case driven well
bored well
dug well
case driven well
best quality
bottom of casing is perforated to allow water in
used with a submergible pump that is lowered into the water source
bored well
an auger is used to drill into the earth
dug well
manual dug by man or machine. lined with concrete, bricks, tile or clay pipes.
not deep
what is a rainwater cistern
a tank with a simple filter of sand/gravel to filter rain water.
used for non drinking purposes
What are weep holes?
holes in tanks so that if water freezes it can escape out of the tank to prevent tank damage from expansion
what is the hydraulic gradient?
the movement of water downward by earths gravitational pull
What is an injection well
a way to dispose of contaminated water into an isolated well. Typically it’s a well into limestone or sandstone.
not allowed anymore. most are closed?
What is an unconfined aquifer
water confined by both upper and lower impermeable layers (typically clay)
usually not vulnerable to contamination
What is an unconfined aquifer
only confined by a lower impermeable layer
What is the purpose of the well casing
prevents the collapse of the bore hole
keeps surface and subsurface pollutants from entering the water source
provides a column to store water for positive well upmp
houses the pump and discharge pipe
What are the two types of casing
blank casing - pvc or steel depending on soil
screened casing - slotted, louvered - to keep sand and gravel out but allow water in
What is an annular seal
a cement or bentonite filling around the open space left around the outside of the well casing.
to prevent contamination
What are two types of pumps used in wells
vertical turbine pump (pump motor is on the surface)
submersible pump (more common)
What percent of Americans are on private wells/drinking water
15%
The recycling of water is known as _________
the hydrologic cycle
Water weights ______ lbs/gallon
8.34
_______ gallons of water are in 1 cubic foot volumne
7.48
What are some gases that can be found in water?
CO2
Oxygen
Hydrogen Sulfide
Methane
CO2 in water
corrosion, especially in steam and condensate lines
treatment: aeration, deaeration, neutralize with alkalies
Oxygen gas in water
O2
corrosion of water lines, heat exchange equipment
treatment: deaeration, sodium sulfite, corrosion inhibitors
Hydrogen Sulfide gas in water
H2S
Rotten Egg odor, Corrosion
treatment: aeration, chlorination, highly basic anion exchange
What is hard water
Water that has a high dissolved mineral content. Typically has a lot of salts and bicarbonates.
Mainly calcium and magnesium
What is the benefit of hard water and the drawbacks of it?
good cleanser for the human circulatory system.
cons: hard water neutralizes soap and makes it hard to lather. stains sinks and bathing areas and calcifies pipes due to electrolysis.
What are some areas with hard water and why?
limestone areas such as Colorado river, Arizona.
south Carolina has the softest water.
calcium concentration must exceed ____ mg/l to be labeled as hard water
100 mg/l
What are the two main ways to soften water?
lime soda process
magnesium soda ash process
Water softening is achieved by increased the ______ concentration which precipitates the calcium and magnesium minerals out of the water
sodium
lime soda process to soften water
quicklime - CaO and H2O is mixedhe slurry is added to the water and calcium ions are precipitated out as insoluble calcium carbonate CaCO3
can’t be done at home
magnesium soda ash process is also called
aka zeolite or ion exchange method
excessively soft water can pull ________ out of the pipes such as ______ and ______ and into the water
pulls metallic ions
such as copper and lead from the pipes into the water
What are some radioactive materials that can get into water? how did they get into the water?
name 3
from mining wastes and improper haz waste disposal
radium
strontium 90
uranium
What is the MCL for strontium 90 a radioactive nuclide?
8 pCi/L
What is the MCL for combined Radium (226 and 228)
5 pCi/L
What is the MCL for Uranium?
20 pCi/L
Which two elements found in water are most known for causing stains
iron and manganese
What are the secondary standards?
limits for other elements in water that may not pose a health risk but my adversely affect the appearance, test, or odor of drinking water
What are the some of the elements addressed in secondary drinking water standards
iron zinc turbidity color odor manganese TDS Sulfates Chlorides
What is the acceptable limit for Iron
.3 mg/L
1 mg/L = ____ ppm
1 they are the same
What are the metals that are monitored in public drinking water?
There are 12
arsenic, barium, cadmium, chromium, lead, copper, mercury, selenium, nickel, thallium, antimony, and beryllium
Copper in water - what are the effects? What is the MCL
mcl is 1 mg/L
can lead to liver damage