Water pollution

Water PollutionWater Pollution

The pollution saga of the nectar of life…

The Blue Marble orthe Blue Sapphire!The Blue Marble orthe Blue Sapphire!

“Our liquid planet glows like a soft blue sapphire in the hard-edged darkness of space. There is nothing else like it in the solar system. It is because of water.” - John Todd

Water and Water issuesWater and Water issues

• Water is an essential thing for life.• Without water life is impossible• How much water is required per person per day?• As per universal standards(Average)* For drinking 5 litres* sanitation 20 litres* Bathing 15 litres* Food preparation 10 litres

Some facts on waterSome facts on water Only 2.5 % of the total water on earth is fresh water About 80 countries or 40% of the world’s population suffering

from water shortages By 2025, 66% of the world population may suffer from serious

water problems Still, 1 billion people lack access to safe drinking water and 2.4

billion lack access to proper sanitation Agriculture accounts for more than 70% of the fresh water

• Fewer than 35% of the cities in the developing world treat their waste water

• Many countries lack adequate legislation and policies for efficient water management

Water management problemsWater management problems

• There is sufficient water in the world.• It is not managed well• Water security was a subject to all the world

countries during the World summit, 2002• Water policy is required by all the nations

What is water pollution?What is water pollution?

Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired usage.

What is water pollution?What is water pollution?

Infectious Agents: bacteria and viruses often from animal wastes

Inorganic Chemicals: Acids and toxic chemicals often from runoff, industries and household cleaners

What is water pollution?What is water pollution?Organic Chemicals: oil, gasoline, plastics,

detergents often from surface runoff, industries and cleaners

Plant Nutrients: water soluble nitrates, ammonia and phosphates often from sewage, agriculture and urban fertilizers

Sediment: soils and silts from land erosion can disrupt photosynthesis, destroy spawning grounds, clog rivers and streams

Pollution and Radioactivity: mostly from powerplants

Impact of water pollutionImpact of water pollution

As per WHO:

• 3.4 million premature deaths each year from waterborne diseases

• 1.9 million die from diarrhea

Types, Effects and Sources of Water PollutionTypes, Effects and Sources of Water Pollution

Point sourcesPoint sources

Nonpoint sourcesNonpoint sources

Water qualityWater quality

Point and Nonpoint SourcesPoint and Nonpoint Sources

NONPOINT SOURCES

Urban streets

Suburban development

Wastewater treatment plant

Rural homes

Cropland

Factory

Animal feedlot

POINT SOURCES

Major Sources of Water PollutionMajor Sources of Water Pollution

Agriculture: by far the leader

• Sediment, fertilizers, bacteria from livestock, food processing, salt from soil irrigation

Industrial: factories and powerplants

Mining: surface mining toxics, acids, sediment

Freshwater Stream PollutionFreshwater Stream PollutionFlowing streams can recover from

moderate level of degradable water pollution if their flows are not reduced.

• Natural biodegradation process

• Does not work if overloaded or stream flow reduced

• Does not work against non biodegradable pollutants

Pollution of StreamsPollution of Streams

Oxygen sag curve Oxygen sag curve Factors influencing recovery Factors influencing recovery

What factors will influence this oxygen sag curve?

Two WorldsTwo Worlds

Developed CountriesU.S. and other developed

countries sharply reduced point sources even with population and economic growth

• Nonpoint still a problem• Toxic chemicals still

problem• Success Thames River

Two WorldsTwo Worlds Developing Countries:

Serious and growing problem

• Half of world’s 500 major rivers heavily polluted

• Sewage treatment minimal $$$

• Law enforcement difficult

• 10% of sewage in China treated

• Economic growth with little $$$ to clean up

India’s Ganges RiverIndia’s Ganges River• Holy River (1 million take

daily holy dip)• 350 million (1/3rd of pop) live

in watershed• Little sewage treatment• Used for bathing, drinking etc.• Bodies (cremated or not)

thrown in river• Good news is the Indian

government is beginning to work on problem

Pollution of LakesPollution of Lakes

Eutrophication Eutrophication

Eutrophication of LakesEutrophication of LakesEutrophication: nutrient

enrichment of lakes mostly from runoff of plant nutrients (nitrates and phosphates)

• During hot dry weather can lead to algae blooms

• Decrease of photosynthesis• Fishes killed, bad odour

Eutrophication in LakesEutrophication in Lakes

Solutions:

• Advanced sewage treatment (N, P)

• Household detergents

• Soil conservation

• Remove excess weed build up

• Pump in oxygen or freshwater

Case Study: The Great LakesCase Study: The Great Lakes•Pollution levels dropped, but long way to go

•95% of U.S. freshwater

•30% Canadian pop, 14% U.S.

•38 million drink

•1% flow out St. Lawrence

•Toxic fish

Section 4: GroundwaterSection 4: Groundwater

• Why is groundwater pollution a serious problem?

• What is the extent of the problem?

• What are the solutions?

GroundwaterGroundwater

Groundwater can become contaminated

• No way to cleanse itself

• Little dilution and dispersion

• Out of sight pollution

• Prime source for irrigation and drinking

• REMOVAL of pollutant difficult

Groundwater Pollution: CausesGroundwater Pollution: Causes

Low flow rates Low flow rates Few bacteria Few bacteria Cold temperatures Cold temperatures

Coal strip mine runoff

Pumping well

Waste lagoon

Accidental spills

Groundwater flow

Confined aquifer

Discharge

Leakage from faulty casing

Hazardous waste injection well

Pesticides

Gasoline station

Buried gasoline and solvent tank

Sewer

Cesspool septic tank

De-icing road salt

Unconfined freshwater aquifer

Confined freshwater aquifer

Water pumping well Landfill

Low oxygen Low oxygen

Fig. 22-9 p. 502

GroundwaterGroundwater

• Pollution moves in plumes

• Soil, rocks, etc. act like sponge

• Cleansing does not work (low O, low flow, cold)

• Nondegradables may be permanent

Prevention is the most effective and cheapest

Groundwater Pollution PreventionGroundwater Pollution Prevention

Monitor aquifers Monitor aquifers

Leak detection systems Leak detection systems

Strictly regulating hazardous waste disposal Strictly regulating hazardous waste disposal

Store hazardous materials above ground Store hazardous materials above ground

Find less hazardous substitutes Find less hazardous substitutes

Ocean PollutionOcean Pollution

• How much pollution can the oceans tolerate?

• Coastal zones: How does pollution affect coastal zones?

• What are major sources of ocean pollution and what is being done?

• Oils spills


Oceans can disperse and break down large quantities of degradable pollution if they are not overloaded.

• Pollution worst near heavily populated coastal zones

• Wetlands, estuaries, coral reefs, mangrove swamps

• 40% of world’s pop. Live within 62 miles of coast

Mangrove Swamp

Estuaries


• Large amounts of untreated raw sewage (viruses)

• Leaking septic tanks• Runoff• Algae blooms from

nutrients• Dead zones NO DO• Airborne toxins• Oil spills


Fig. 22-11 p. 504

Case Study: Chesapeake BayCase Study: Chesapeake Bay

Largest US estuary

Largest US estuary

Relatively shallow Relatively shallow

Slow “flushing” action to Atlantic

Slow “flushing” action to Atlantic

Major problems with dissolved O2 Major problems with dissolved O2

Fig. 22-13 p. 506

Preventing and reducing the flow of pollution from land and from streams emptying into the ocean is key to protecting oceans

Oil SpillsOil Spills Sources: offshore wells, tankers, pipelines and

storage tanks

Sources: offshore wells, tankers, pipelines and storage tanks

Effects: death of organisms, loss of animal insulation and buoyancy, smothering

Effects: death of organisms, loss of animal insulation and buoyancy, smothering

Significant economic impacts Significant economic impacts

Mechanical cleanup methods: skimmers and blotters

Mechanical cleanup methods: skimmers and blotters

Chemical cleanup methods: coagulants and dispersing agents

Chemical cleanup methods: coagulants and dispersing agents

Oil SpillsOil Spills

Prevention and ReductionPrevention and Reduction

• How can we reduce surface water pollution: point and also nonpoint.

• How do sewage treatment plants work?

• How successful has the U.S. been at reducing water pollution? Clean Water Act

Solutions: Preventing and Reducing Surface Water PollutionSolutions: Preventing and Reducing Surface Water Pollution

Nonpoint SourcesNonpoint Sources Point SourcesPoint Sources

Reduce runoffReduce runoffBuffer zone

vegetation

Buffer zone vegetation

Reduce soil erosionReduce soil erosion

Clean Water ActClean Water Act

Water Quality ActWater Quality Act

Only apply pesticides and fertilizers as needed Only apply pesticides and fertilizers as needed

Nonpoint SourcesNonpoint Sources

Reduce runoff

Nonpoint SourcesNonpoint Sources

Buffer Zones Near Streams

NonpointNonpoint

Prevent soil erosion and only apply needed pesticides and fertilizers

Point SourcesPoint Sources

Most developed countries use laws to set water pollution standards.

• Regulates navigable waterways..streams, wetlands, rivers, lake

Clean Water ActClean Water Act• Sets standards for key

pollutants• Requires permits for

discharge• Requires sewage treatment• Require permits for

wetland destruction• Does not deal with

nonpoint sources well• Goal All Waterways

fishable and swimable

Technological Approach: Septic SystemsTechnological Approach: Septic Systems

Require suitable soils and maintenanceRequire suitable soils and maintenance

Fig. 22-15 p. 510

•¼ of all U.S. homes have Septic tanks

•Can be used in parking lots, business parks, etc.

Combined sewer overflow is a problem in many older towns

•EPA: 1.8 M to 3.85 M sick from swimming in water contaminated by sewer overflows

•EPA: $100 billion to fix

Technological Approach: Sewage TreatmentTechnological Approach: Sewage Treatment

Physical and biological treatmentPhysical and biological treatmentFig. 22-16 p. 511

Primary: removes 60% of solids and 30-40% oxygen demanding wastes (physically)

Secondary: uses biological processes to remove up to 90% of biodegradables

Tertiary: advanced techniques only used in 5% of U.S. $$$$

Disinfection: chlorine, ozone, UV

What is not taken out???

Technological Approach: Advanced (Tertiary) Sewage TreatmentTechnological Approach: Advanced (Tertiary) Sewage Treatment

Uses physical and chemical processesUses physical and chemical processes

Removes nitrate and phosphateRemoves nitrate and phosphate

ExpensiveExpensive

Not widely usedNot widely used

Sludge disposal…using as fertilizer

Technological Approach: Using Wetlands to Treat SewageTechnological Approach: Using Wetlands to Treat Sewage

Fig. 22-18 p. 513

Rain Water HarvestingRain Water Harvesting • Rain Water Harvesting RWH- process of collecting, conveying & storing water from rainfall in an area – for beneficial use.

• Storage – in tanks, reservoirs, underground storage- groundwater

• Hydrological Cycle

Appropriate Technology

Water conservation and groundwater recharge techniques

Water harvesting cum supplementary irrigation techniques

The Good NewsThe Good News

Largely thanks to CWA:• Between 1972 – 2002

fishable and swimmable streams 36% to 60%

• 74% served by sewage treatment

• Wetlands loss dropped by 80%

• Topsoil losses dropped by 1 billion tons annually

The Bad NewsThe Bad News

• 45% of Lakes, 40% streams still not fishable and swimmable

• Nonpoint sources still huge problem

• Livestock and Ag. Runoff• Fish with toxins

Drinking WaterDrinking Water

• How is drinking water purified? High tech way.

• How can we purify drinking water in developing nations?

• What is the Safe Drinking Water Act?

• Is bottled water a good answer or an expensive rip-off?

Drinking Water QualityDrinking Water Quality

Safe Drinking Water Act Safe Drinking Water Act

Maximum contaminant levels (MCLs) Maximum contaminant levels (MCLs)

Purification of urban drinking water Purification of urban drinking water

Bottled water Bottled water

Protection from terrorism Protection from terrorism

Purification of rural drinking water Purification of rural drinking water

Purification of urban drinking waterPurification of urban drinking water

Surface Water:

• Removed to reservoir to improve clarity

• Pumped to a treatment plant to meet drinking water standards

Groundwater: often does not need much treatment

Purification of rural drinking waterPurification of rural drinking water

There can be simple ways to purify water:

• Exposing to heat and UV rays

• Fine cloths to filter water

• Add small amounts of chlorine

Safe Drinking Water ActSafe Drinking Water Act

• 54 countries have drinking water laws

SDWA passed 1974 requires EPA to set drinking water standards

Maximum Contaminating Levels (MCLs)

Safe Drinking Water ActSafe Drinking Water Act

• Privately owned wells exempt from SDWA

SDWA requires public notification of failing to meet standards and fine.

MCLs often stated in parts per million or parts per billion

Bottle WaterBottle Water

U.S. has the world’s safest tap water due to billions of $$$ of investment

Bottle water 240 to 10,000 times more expensive than tap water

25% of bottle water is tap water

Bottle WaterBottle Water1.4 million metric tons of

bottle thrown away each year

Toxic fumes released during bottling

Bottles made from oil based plastics

Water does not need to meet SDWA

Environment

Water pollution