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) 341-5514jmarshack@waterboards.ca.gov

Major Concepts

Sources and types of pollutionthat threaten water supplies

Point sources & nonpoint sources

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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

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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

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ChemicalBiologicalRadioactive

Types of Pollution

Inorganic chemicalsOf particular concern are metals• Lead, cadmium, mercury, arsenic, copper

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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

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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

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• 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

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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%

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Industrial6%

Municipal11%

Unknown4%

3%

Hydro / habitat modification

10%

Combined storm sewers

& runoff8%

Sources of Pollution

Point sourcesIndustrial discharges andmunicipal wastewater treatment plants

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• Regulated under federal Clean Water Act• National Pollutant Discharge

Elimination System (NPDES) permitsUnderground injection wells

Sources of Pollution

Nonpoint sourcesAgricultural runoff

• Pesticides

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• 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

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• 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

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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

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FiltrationDisinfection

Disinfection

Most critical step in water treatmentGoal: destroy all organismsin water supply

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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)

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• 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

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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

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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

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Shows level of dissolved oxygen over timeShows “critical point”

• Minimum dissolved oxygen• Maximum aquatic life impact

BOD and Sag Curve

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Types of Sewage Disposal

Pit priviesIndividual septic systemsMunicipal sewage treatment plant

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p g p

Pit Privy

Separation from water

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Drainage

Ventilation

Individual SepticSystem

Septic tank

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Leach field

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EPP 262, Principles of Environmental Health SciencesWater and Wastewater – Part 2

Jon B. Marshack, D.Env.State Water Resources Control Board Page 5

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Prevent Septic System Failure

Proper installationSeparation from water sourcesSoil properties - drainage

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Keep microorganisms healthyMinimize toxins

Don’t overload with solidsGrease, fats, food wastesRemove solids periodically

Municipal Sewage Treatment

Speeds up natural purification processesSettlingBiooxidationFiltration

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FiltrationStages of treatment

PrimarySecondaryTertiarySludge disposal

d Se

cond

ary

r T

reat

men

t

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Prim

ary

and

Was

tew

ater

Municipal Sewage Treatment

Primary treatmentMechanical processes for removal of solids

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Bar screenGrinder or comminuterClarifier

Bar Screen

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EPP 262, Principles of Environmental Health SciencesWater and Wastewater – Part 2

Jon B. Marshack, D.Env.State Water Resources Control Board Page 6

Comminuter

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Clarifier

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Clarifier

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Municipal Sewage Treatment

Secondary treatmentTrickling filters andactivated sludge treatment

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• 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

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Activated Sludge Tank

(drained)

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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

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Sludge Composting

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Municipal Sewage Treatment

Tertiary treatmentAdvanced wastewater treatment methods, including

f

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• 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

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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

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we must promote conservation, efficiency, and frugality.

Every drop counts!

www.waterboards.ca.gov

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