Transcript Thanks!
Welcome! Please pass back the news article and the graphic organizer. Please read the board and note the HOMEWORK CHANGE!! Thanks! Have you ever been in a place where you can’t drink the water? CLEAN WATER Pollutant of the Day! Pathogens World Health Organization Statistics: Concerns: Improvements: 2.6 billion people do 84% of the population not have adequately clean water rural habitants are 5 times less likely to use improved drinking water than those in urban centers. in developing regions are using an improved source; in 2000, 1 billion more people used such a source than in 1990. One out of four urban dwellers UN-Water Decade Programme on Advocacy and Communication 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 It’s not just developing nations. WHAT HAPPENS WHEN AN URBAN AREA EXPANDS FASTER THAN ITS INFRASTRUCTURE WILL ALLOW? Bacterial pathogens E. Coli – diarrhea, vomiting, abdominal pain Typhoid – diarrhea, severe vomiting, inflamed intestines Cholera – diarrhea, severe vomiting Dysentery – 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 knowledge Disruption 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? Septic Tanks – out in the country trap greases & large solids & discharges the remaining wastes underneath a field Stay in school, kids! Fig. 12–26 © Brooks/Cole Publishing Company / ITP Septic Tanks – out in the country trap greases & large solids & discharge the remaining wastes over drainage field 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 Primary Treatment involves screens & settling tanks to remove solids from sewage Fig. 12–27 © Brooks/Cole Publishing Company / ITP Bar screen First settling tank Secondary Treatment uses biological processes to break down biodegradable, oxygen–demanding wastes 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 Advanced Treatment Uses chemical reactions to remove one or more specific pollutants Fig. 12–28 © Brooks/Cole Publishing Company / ITP 1. Screening 2. Coagulation alum 3.Sedimentation 4. Filtration 5. disinfection: chlorine UV rays ozone Water vs. Sewage treatment Check for understanding Name one bacterial pathogen Name one parasitic worm How 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?