Transcript Slide 1 - Winston-Salem/Forsyth County Schools

QUOTE FOR THE DAY
I DON’T NEED DRUGS. I AM DRUGS.
WARS HAVE NEVER HURT ANYBODY EXCEPT
THE PEOPLE WHO DIE.
- SALVADOR DALI -
LITTLE KNOWN FACTS
It is impossible to lick your elbow.
The percentage of Africa that is wilderness - 28%
The percentage of North America that is
wilderness - 38%
The cost of raising a medium sized dog to the
age of eleven - $16,400
WATER TREATMENT
HISTORY OF DRINKING WATER
TREATMENT
• METHODS TO IMPROVE THE TASTE AND ODOR OF DRINKING
WATER WERE RECORDED AS EARLY AS 4000 BC
• THE EGYPTIANS WERE USING ALUM TO REMOVE
SUSPENDED PARTICLES AS EARLY AS 1500 BC
• BY THE EARLY 1800s FILTRATION WAS BEING REGULARLY
USED IN EUROPE
• IN 1885, DR JOHN SNOW PROVED THAT CHOLERA WAS A
WATER BORNE DISEASE
• IN 1908 CHLORINE WAS USED FOR THE FIRST TIME AS A
DISINFECTANT
• FEDERAL DRINKING WATER STANDARDS WERE FIRST
ESTABLISHED IN 1914 IN THE U.S.
GOAL OF WATER TREATMENT:
1. REMOVE SOLIDS
2. REMOVE MICROORGANISMS
3. REMOVE CHEMICALS
THERE ARE OVER 160,000 PUBLIC WATER
SYSTEMS NATIONWIDE.
THE SAFE DRINKING WATER ACT (SDWA) WAS
PASSED IN 1974 TO PROTECT DRINKING
WATER AND ITS SOURCES.
IT WAS AMMENDED IN 1986 AND 1996.
IT REQUIRES TESTING FOR 90 CHEMICAL,
MICROBIOLOGICAL, PHYSICAL, AND
RADIOLOGICAL CONTAMINANTS.
THE STANDARDS ARE HEALTH BASED.
THERE ARE ALSO SECONDARY STANDARDS
THAT EPA DOES NOT ENFORCE, BUT STATES MAY
ADOPT.
THESE RELATE TO COSMETIC AND AESTHETIC
EFFECTS.
BOTTLED WATER IS REGULATED BY THE U.S. FDA
AS A FOOD PRODUCT.
IT IS REQUIRED TO MEET STANDARDS
EQUIVALENT TO THOSE THE U.S. EPA SETS FOR
TAP WATER.
THE STANDARDS ARE SET FOR MAXIMUM
CONTAMINANT LEVELS (MCL’S) OF
SUBSTANCES ALLOWED IN WATER.
A LIST OF CONTAMINANTS MAY BE FOUND ON
EPA’S WEB SITE AT:
http://www.epa.gov/safewater/contaminants/index.
html
EPA ALSO MAINTAINS A LIST OF CONTAMINANT
CANDIDATES.
THESE ARE CONTAMINANTS THAT HAVE BEEN
IDENTIFIED AND MAY BE ADDED TO THE LIST IF
CONCENTRATIONS REACH PROBLEM LEVELS.
EPA IS ALSO CONCERNED WITH RESIDUAL
LEVELS OF DISINFECTANTS AND BYPRODUCTS
OF DISINFECTANTS.
DISINFECTANTS CAN REACT WITH NATURALLY
OCCURING SUBSTANCES TO FORM COMPOUNDS
WITH POSSIBLE HEALTH EFFECTS.
DRINKING WATER TREATMENT:
1. COARSE FILTRATION
2. pH ADJUSTMENT
3. FLOCCULATION
4. SEDIMENTATION
5. FILTATION
6. DISINFECTION
7. AERATION
8. ADDITIONAL TREATMENT, E.G. FLUORIDE
1. COARSE FILTRATION – GET RID OF THE ROCKS,
LEAVES, STICKS, BODIES, ETC.
2. pH ADJUSTMENT – NEEDS TO BE SLIGHTLY
ABOVE 7 IN ORDER FOR THE FLOCCULATION TO
WORK
3. FLOCCULATION – ADDITION OF ALUM, WHICH IS
POTASSIUM ALUMINUM SULFATE – FORMS
GELATINOUS PARTICLES THAT BACTERIA AND
VERY SMALL PARTICLES STICK TO.
FLOCCULATION ALSO REMOVES COLOR, SO YOU
CAN THINK OF IT AS A CLARIFICATION PROCESS.
4. SEDIMENTATION – THIS HAPPENS IN A LARGE
BASIN SO THAT THE PARTICLES HAVE A CHANCE
TO SETTLE TO THE BOTTOM. AFTER
SEDIMENTATION, THE FLOC IS REMOVED,
TREATED, AND DISPOSSED.
TYPICAL TRANSIT TIME IS AROUND 4 HOURS.
5. FILTRATION – GENERALLY, SAND OR SAND AND
CHARCOAL OR ANTHRICITE COAL IS USED.
FILTRATION GENERALLY REMOVES ALL BACTERIA
AND PROTOZOA.
6. DISINFECTION – TO REMOVE ANY BACTERIA
THAT STILL MAY REMAIN AND TO KILL VIRUSES,
SOME TYPE OF DISINFECTANT STEP IS USUALLY
USED.
MOST COMMON DISINFECTANTS ARE CHLORINE,
UV LIGHT, AND OZONE.
THERE IS SOME DANGER IN USING CHLORINE, AS
REACTION BYPRODUCTS CAN BE
CARCINOGENIC. HOWEVER, THE BENEFITS FAR
OUTWEIGHT THE RISKS.
GOAL OF WATER TREATMENT:
1. REMOVE SOLIDS
2. REMOVE MICROORGANISMS
3. REMOVE CHEMICALS
WINSTON-SALEM WASTEWATER TREATMENT
WASTEWATER TREATMENT PROCESS:
1. SEWER CONNECTIONS DRAIN WATER FROM
TOILETS, ETC. INTO A GRAVITY SEWER
2. GRAVITY SEWERS FLOW DOWNHILL TO SEWER
INTECEPTORS.
3. INTECEPTORS SEND SEWAGE TO TREATMENT
PLANT WITH HELP OF PUMP STATIONS.
4. SEWAGE FLOWS THROUGH A BAR SCREEN TO
REMOVE LARGE OBJECTS.
5. IN THE GRIT CHAMBER, THE FLOW OF SEWAGE
IS SLOWED TO ALLOW ROCKS AND SAND TO
SETTLE AND BE REMOVED.
6. IN THE PRIMARY CLARIFER, SOLIDS FALL TO THE
BOTTOM AND FORM A SLUDGE. THAT ALONG WITH
THE SCUM FLOATING ON THE SURFACE ARE
REMOVED AND SENT TO DIGESTORS.
7. THE PRIMARY CLARIFIED WASTEWATER GOES TO
AN ACTIVATED SLUDGE BASIN. AIR IS PUMPED TO
SPEED THE PROCESS.
8. THE FINAL CLARIFER SEPARATES WATER FORM
SOLIDS FORMED IN THE ACTIVATED SLUDGE
PROCESS.
9. CHLORINE IS ADDED TO KILL REMAINING
BACTERIA.
10. THE WASTEWATER FLOWS THROUGH A
CONTACT BASIN TO GIVE THE CHLORINE TIME TO
ACT (~90 MINUTES).
11. THE WASTEWATER IS DECHLORINATED AND
THEN DISCHARGED INTO A STREAM.
THE SLUDGE FROM THE ACTIVATED SLUDGE
PROCESS IS FURTHER TREATED AND THEN
HAULED TO FARMS OR LANDFILL.
IN THE 2006-2007 OPERATING YEAR, THE
WINSTON-SALEM/FORSYTH COUNTY PLANTS
TREATED 12.49 BILLION GALLONS OF
WASTEWATER.
THEY REMOVED 97.2% OF THE REGULATED
POLLUTANTS THEY RECEIVED.
CAMPING AND BACKPACKING
PROTOZOAN CYSTS - HARD SHELLED
PROTOZAN PARISITES
GIARDIA AND CRYPTOSPORIDIA
(RESISTANT TO IODINE AND CHLORINE)
CAN BE REMOVED BY 0.2 OR 0.3 MICRON
FILTERS
BACTERIA - SMALLER
CHOLERA, E. COLI, SALMONELLA ARE
EXAMPLES
CAN ALSO BE REMOVED BY FILTRATION
VIRUSES - CAN SLIP THROUGH MOST
FILTERS
HEPATITIS A IS AN EXAMPLE
CAN BE KILLED BY CHEMICAL TREATMENT
BEFORE OR AFTER FILTRATION, BY BOILING,
OR UV LIGHT
BOILING IS EFFECTIVE AGAINST PROTOZOAN
CYSTS, BACTERIA, AND VIRUSES.
IODINE AND CHLORINE CAN KILL BACTERIA
AND VIRUSES. PROTOZOAN CYSTS CAN BE
RESISTANT.
FILTRATION CAN REMOVE PROTOZOA AND
BACTERIA.
SOME FILTERS HAVE BUILT IN CHEMICALS
FOR ALSO REMOVING VIRUSES.
STAY AWAY FROM AREAS OF ANIMAL AND
HUMAN ACTIVITY.