Please pass back the news article and the graphic organizer.

Please read the board and note the HOMEWORK CHANGE!!

Thanks!

Welcome!

CLEAN WATER

Have you ever been in a place where you can’t drink the

water?

Pollutant of the Day!

Pathogens

Concerns:Concerns: Improvements:Improvements:

2.6 billion people do not have adequately clean water

rural habitants are 5 times less likely to use improved drinking water than those in urban centers.

84% of the population in developing regions are using an improved source;

in 2000, 1 billion more people used such a source than in 1990.

World Health Organization Statistics:

UN-Water Decade Programme on Advocacy and Communication

One out of four urban dwellers does not have access to improved sanitation facilities.

90% of all waste water in developing countries is discharged untreated, polluting rivers, lakes and seas.

Every day, 2 million tons of sewage and other effluents drain into the world's waters

WHAT HAPPENS WHEN AN URBAN AREA EXPANDS FASTER THAN ITS INFRASTRUCTURE WILL ALLOW?

It’s not just developing nations.

Bacterial pathogens

E. Coli – diarrhea, vomiting, abdominal painTyphoid – diarrhea, severe vomiting, inflamed

intestinesCholera – diarrhea, severe vomitingDysentery – diarrhea, usually only fatal in

infants

Giardia protezoan – diarrhea, cramps, fatigue

Schistosomiasis – parasitic worm

Guinea worm – burns as it leaves the human body

'Fiery serpent' ... A guinea worm emerges from the leg of a south Sudanese girl. (Reuters: Skye Wheeler, file photo)

How are all of these passed on?

Lack of options (poor sanitation – no/few toilets, vulnerable water sources)

Lack of knowledgeDisruption of

water/sewage infrastructure (earthquakes, storms)

Global water initiatives

The Life Straw

LifeStraw Swiss-based Vestergaard Frandsen for tourists and people living in developing nations. There are several models of the product: LifeStraw Personal filters a minimum of 700 litres of water, enough for one person and one year. LifeStraw Family filters a minimum of 18,000 litres of water, providing safe drinking water for a family for more than two years. It removes 99.9999% of waterborne bacteria, 99.99% of viruses, and 99.9% of parasites. LifeStraw Personal kills 99.9999% of waterborne bacteria and 98.5% of viruses.

OK, so what happens to water in the US?

trap greases & large solids & discharges the remaining wastes

underneath a field

Septic Tanks – out in the Septic Tanks – out in the countrycountry

Fig. 12–26© Brooks/Cole Publishing Company / ITP

Stay in school, kids!

trap greases & large solids & discharge the remaining wastes over

drainage field

Septic Tanks – out in the Septic Tanks – out in the countrycountry

Fig. 12–26© Brooks/Cole Publishing Company / ITP

OK, so what happens to MY water?

Sewage treatment in town

Goal – remove pathogens, solids, and to return water to the watershed

What natural processes are used? (diagram)

Sewage treatment

Sedimentation Aeration Chlorination (Dechlorination)Solids

involves screens & settling tanks to remove solids from sewage

Primary TreatmentPrimary Treatment

Fig. 12–27© Brooks/Cole Publishing Company / ITP

Bar screen

First settling tank

uses biological processes to break down biodegradable, oxygen–demanding wastes

Secondary TreatmentSecondary Treatment

Fig. 12–27© Brooks/Cole Publishing Company / ITP

Aeration tank

Second Settling Tank

Settling tank

Dripping chlorine into the water

Clarified water leaving treatment plant

Water from Turkey creek sewage treatment enters Buffalo Bayou

Uses chemical reactions to remove one or more specific pollutantsAdvanced TreatmentAdvanced Treatment

Fig. 12–28 © Brooks/Cole Publishing Company / ITP

1. Screening

2. Coagulationalum

3.Sedimentation

4. Filtration

5. disinfection:chlorineUV raysozone

Water vs. Sewage treatment

Check for understanding

Name one bacterial pathogenName one parasitic wormHow do human pathogens get into our water

supply?How will you remember that primary sewage

treatment is physical?Name one action that primary treatment involves.Why is oxygen bubbled through sewage during

secondary treatment?Why is tertiary treatment rare?