1/29/99

Public Health

 

Water-H2O

Molecule of life-Biological stand point

Universal solvent-transportation

-drinking, cooking, washing, cleaning (ablution)

-industry (hydraulic, steam, coolant), recreation,

-6-8 glasses of water drank a day

-gallon/day for cooking

-1800 gallon/day purified everyday per person

-handout 13

-ch 26 p743-746, table 26.1

-sewage is carry of offensive items and microorganisms

-waste water

 

Sources of water

-fixed amount of water on Earth

-fig

snow caps 2.225%

.303% in ground >1000m

fresh water .009

glaciers.015% saline lakes .007

rivers .0001%

ground moisture .003%

ground water at 1000m .0303%

Aquifer-ogalala--largest fresh water area in US

 

Purification of water

-aeration-method fresh air is blown through the body of water for the purpose of remove dissolved gases, precipitates metallic impurities like Fe, Mn, remove turbidity (odor), microbes lowered in number

-coagulation (flocculation, agglomeration, precipitation)-removal of suspended impurities--decantation

-accomplished by use of chemicals

-sedimentation

-used on large scale municipality

-filtration-universally used

      media-gravel

            sand filters 7 inches thick

      -absorption

      -sieve

-softening of water

      -zeolite filters--replace Ca++ and Mg++ w/ Na+ in water

-disinfection - Chlorination (Na+, K+ hypchlortes) -p747, 748