Water Treatment and Quality

Question 1

fresh water

Answer 1

water that is not salty. Most of this fresh water is in the form of polar ice

Question 2

ground water

Answer 2

water that seeps through the ground below the surface. Not accessible because it is in remote locations or too far below Earth’s surface.

Question 3

surface water

Answer 3

( lakes, rivers, reservoirs etc) is a tiny fraction of Earth’s water

Question 4

• what is meant by water quality

Answer 4

• Water quality describes the condition of the water, including chemical, physical, and biological characteristics, usually with respect to its suitability for a particular purpose such as drinking or swimming
• is affected by substances that have dissolved in it. Many ions that are in water are found from more than one category of sources

Question 5

harmful substances found in water (natural and from 
human activities)

Answer 5

• rain and snow contain dissolved gases from the atmosphere
• CO2 gas dissolves in water resulting in dilute solution of carbonic acid (dissolves compounds in soil and rocks)
• arsenic (found naturally but long term exposure can cause cancer), calcium and magnesium (cause hard water)

Question 6

• Beneficial substances found in water (natural and from 
human activities)

Answer 6

• Fluoride?

Question 7

• Beneficial substances found in water (natural and from 
human activities)

Answer 7

• Fluoride, calcium, iron,

Question 8

• How do good and bad substances get into the water supply

Answer 8

run-off, point sources and non-point sources.

Question 9

point source

Answer 9

pollution has a single source with specific location (leaking oil or pulp mill)

Question 10

Non-point source

Answer 10

does not come from a single, easily defined location such as pesticides and fertilizers. Can be combinations of thousands of different sources

Question 11

soft water

Answer 11

water that contains small concentrations of ions that form insoluble compounds with soap

Question 12

permanent hardness

Answer 12

can’t be removed by boiling, only by chemical methods but water can be turned basic by this. Use ion-exchange water softeners to stop basic water from forming

Question 13

• Ion exchange water softeners

Answer 13

CHECK IF YOU NEED TO KNOW

Question 14

desalination

Answer 14

CHECK IF YOU NEED TO KNOW- the process of obtaining fresh water from salt water
- potable water: water that is safe to drink

Question 15

reverse osmosis

Answer 15

CHECK IF YOU NEED TO KNOW- process of using high pressure to force water from a concentrated solution through a semi-permeable membrane to get a less concentrated solution
- there are aso reverse osmosis desalination plants

Question 16

hard water

Answer 16

it is hard to form a lather with soap. - another sign of hard water is calcium carbonate (called lime scale) that build up inside water pipes, kettles and humidifiers. Vinegar helps to remove this.

Question 17

temporary hardness

Answer 17

can be removed by boiling the water