water and wastewater · jon b. marshack, d.env. state water resources control board page 2 types of...
TRANSCRIPT
EPP 262, Principles of Environmental Health SciencesWater and Wastewater – Part 2
Jon B. Marshack, D.Env.State Water Resources Control Board Page 1
Water and WastewaterWater and WastewaterPart 2: General Concepts
SPH 262Principles of Environmental Health Sciences
Jon B. Marshack, D.Env.Staff Environmental ScientistState Water Board
(916) [email protected]
Major Concepts
Sources and types of pollutionthat threaten water supplies
Point sources & nonpoint sources
2
Clean Water ActSafe Drinking Water ActWastewater treatment
Septic systems & wastewater treatment plantsBiological oxygen demand & sag curve
Water Quality
Characteristics of waterTaste, color, temperature, purity, toxicity
Water quality requirements varyith i t d d
3
with intended useHigh quality needed for drinking water and certain industrial usesLower quality may be acceptable for irrigation
• Wastewater reuse
Water Quality
Types of pollutants that may pollute a water supply
Physical
4
ChemicalBiologicalRadioactive
Types of Pollution
Inorganic chemicalsOf particular concern are metals• Lead, cadmium, mercury, arsenic, copper
5
Can cause serious acute and chronic health problemsSources include• Mining and manufacturing• Agriculture• Households• Arial deposition from fossil fuel burning
Types of Pollution
Organic chemicalsVolatile organic compounds (VOCs)• Solvents, petroleum fuels, fuel additives
6
Synthetic organic compounds (SOCs)• Pesticides, dioxins, PCBs
Sources include• Industry• Agriculture• Households
EPP 262, Principles of Environmental Health SciencesWater and Wastewater – Part 2
Jon B. Marshack, D.Env.State Water Resources Control Board Page 2
Types of Pollution
Biological – waterborne disease1 million illnesses each year in U.S.Bacteria
7
• Typhoid fever, cholera, bacillic dysenteryViruses
• Viral hepatitis, acute gastroenteritisParasites
• Amebic dysentery, giardiasis
Types of Pollution
RadioactiveMost common in water are• Radium, uranium, radon and
d di lid
8
man-made radionuclidesNaturally occurring radionuclidesappear mainly in groundwaterSurface waters more likely to contain artificial radionuclides• Atmospheric fallout from nuclear testing
Sources of Pollution in U.S. Rivers
Agriculture39%Land disposal
3%
Silviculture6%
Resource extraction
9%
Construction4%
9
Industrial6%
Municipal11%
Unknown4%
3%
Hydro / habitat modification
10%
Combined storm sewers
& runoff8%
Sources of Pollution
Point sourcesIndustrial discharges andmunicipal wastewater treatment plants
f C
10
• Regulated under federal Clean Water Act• National Pollutant Discharge
Elimination System (NPDES) permitsUnderground injection wells
Sources of Pollution
Nonpoint sourcesAgricultural runoff
• Pesticides
11
• Nutrients (fertilizers) – cause eutrophication• Sediment
Urban storm water• Pesticides• Nutrients (fertilizers)• Sediment• Petroleum
Sources of Pollution
Nonpoint sources (cont.)Acid mine drainage
• Expose ore and waste rock to atmosphere
12
• Sulfide minerals oxidize low pH (acidic)• Mobilizes metals and salts
Confined animal facilities• Nitrate• Organic matter• Pathogens• Hormones, antibiotics
EPP 262, Principles of Environmental Health SciencesWater and Wastewater – Part 2
Jon B. Marshack, D.Env.State Water Resources Control Board Page 3
Drinking Water Treatment
Municipal drinking water treatment in the United States
170,000 public water supply systems
13
supply most drinking water• 115,000 small scale suppliers• 55,000 community supply systems
Supply water to 250 million Americans
Drinking Water Treatment
Main treatment stepsCoagulation - flocculationSedimentation
14
FiltrationDisinfection
Disinfection
Most critical step in water treatmentGoal: destroy all organismsin water supply
15
ChlorineMajor disinfectant used in U.S. todayForm disinfection byproducts
AlternativesUV radiationOzoneChloramines
Drinking Water Regulation
Safe Water Drinking ActU.S. Environmental Protection Agency sets Maximum Contaminant Levels (MCLs)
16
• Protect the public health and welfarefrom specific water pollutants
Delegated enforcement to individual states• Oversight provided by the USEPA
Wastewater Treatmentand Disposal
SewageIn many developing countrieshuman waste pollutes land and water
17
Organic material can serve as foodfor disease-producing organisms living in the water
Biological Oxygen Demand (BOD)
As microorganisms decompose organic material in water, they use dissolved oxygenIf water overloaded with biodegradable organic pollutants decomposition can
18
organic pollutants, decomposition can deplete dissolved oxygen supply Kills fish and other aquatic organisms that depend on dissolved oxygen for respirationReaeration of water caused by
Turbulent flowAquatic plant photosynthesis
EPP 262, Principles of Environmental Health SciencesWater and Wastewater – Part 2
Jon B. Marshack, D.Env.State Water Resources Control Board Page 4
Biological Oxygen Demand (BOD)
Sag curve Deoxygenation and reaeration of water presented graphically
19
Shows level of dissolved oxygen over timeShows “critical point”
• Minimum dissolved oxygen• Maximum aquatic life impact
BOD and Sag Curve
20
Types of Sewage Disposal
Pit priviesIndividual septic systemsMunicipal sewage treatment plant
21
p g p
Pit Privy
Separation from water
22
Drainage
Ventilation
Individual SepticSystem
Septic tank
23
Leach field
24
EPP 262, Principles of Environmental Health SciencesWater and Wastewater – Part 2
Jon B. Marshack, D.Env.State Water Resources Control Board Page 5
25
Prevent Septic System Failure
Proper installationSeparation from water sourcesSoil properties - drainage
26
Keep microorganisms healthyMinimize toxins
Don’t overload with solidsGrease, fats, food wastesRemove solids periodically
Municipal Sewage Treatment
Speeds up natural purification processesSettlingBiooxidationFiltration
27
FiltrationStages of treatment
PrimarySecondaryTertiarySludge disposal
d Se
cond
ary
r T
reat
men
t
28
Prim
ary
and
Was
tew
ater
Municipal Sewage Treatment
Primary treatmentMechanical processes for removal of solids
29
Bar screenGrinder or comminuterClarifier
Bar Screen
30
EPP 262, Principles of Environmental Health SciencesWater and Wastewater – Part 2
Jon B. Marshack, D.Env.State Water Resources Control Board Page 6
Comminuter
31
Clarifier
32
Clarifier
33
Municipal Sewage Treatment
Secondary treatmentTrickling filters andactivated sludge treatment
34
• Bacteria break down and digestorganic material in the sewage
Sludge from primary and secondary treatment
• Dried• Disposed of in landfill or composted
Activated Sludge Tank
35
Activated Sludge Tank
(drained)
36
EPP 262, Principles of Environmental Health SciencesWater and Wastewater – Part 2
Jon B. Marshack, D.Env.State Water Resources Control Board Page 7
Sludge Drying
Centrifuge
37
Sludge Composting
38
Municipal Sewage Treatment
Tertiary treatmentAdvanced wastewater treatment methods, including
f
39
• Air stripping of ammonia• Coagulation• Rapid granular filtration• Reverse osmosis – membrane filtration
Further reduce BOD, salts, pathogensand other pollutants
Municipal Sewage Treatment
Sludge treatment and disposalSludge or “biosolids”
• Solids and associated liquids separated from wastewater during sewage treatment
40
g gSludge disinfection• Destroys pathogens in the sludge
to prevent the spread of diseaseDigested sludge may be air driedDisposal in landfill or reused as agricultural fertilizer
Future Outlook
On a planet covered with water,yet plagued by waterborne disease,
drought, and water mismanagement,i
41
we must promote conservation, efficiency, and frugality.
Every drop counts!
www.waterboards.ca.gov
42