Water Pollution
• Causes illness and death in humans and other
species and disrupts ecosystems.
• The chief source of water pollution are agricultural
activities, industrial facilities, and mining, but
growth in population and resource use make it
increasingly worse.
• Lake Washington and Puget Sound are a great
example of identifying pollution and then
educating people to help fix the problem.
• 3.2 million people die prematurely every year from
infected water.
• 1.2 billion people do not have access to clean
drinking water.
• 1.9 million people die of diarrhea each year
Major water pollutants and their Sources
Examples
Type and Effects
Major Sources
Infectious agents
(pathogens) cause diseases
Bacteria, Viruses, Protozoa, Parasites
Human and animal wastes
Oxygen Demanding wastes
deplete dissolved oxygen needed by aquatic species
Biodegradable animal wastes and plant debris
Sewage, animal feedlots, food processing facilities,
pulp mills
Plant Nutrients
Cause excessive growth of algae and other species.
Nitrates (NO3-) and Phosphates (PO4-)
Sewage, animal wastes, inorganic fertilizers
Organic Chemicals
add toxins to aquatic system
Oil, gasoline, plastics, pesticides, cleaning solvents
Industry, farms, households
Inorganic Chemicals
add toxins to aquatic system
Acids, bases, salts, metal compounds
Industry, households, surface runoff
Sediments
Disrupt photosynthesis food webs, other processes
Soil, Silt
Land erosion
Heavy Metals
cause cancer, disrupt immune and endocrine systems
Lead, mercury, arsenic
Unlined landfills, household chemicals, mining
refuse, industrial discharges
Thermal
make some species vulnerable to disease
Heat
Electric power and industrial plants
Type of Organism
Diseases transmitted to humans through contaminated drinking
water
Disease/Effects
Bacteria
Typhoid Fever - Diarrhea, severe vomiting, enlarged spleen, inflamed intestine, often fatal
if untreated
Cholera – Diarrhea, severe vomiting, dehydration; often fatal if untreated
Bacterial Dysentery – Diarrhea, bleeding; rarely fatal except in infants without proper
treatment
Enteritis – Severe stomach pain, nausea, vomiting, rarely fatal
Viruses
Infectious Hepatitis (Type B) – Fever, severe headache, loss of appetite, abdominal pain,
jaundice, enlarged lever; rarely fatal, but may cause permanent liver damage.
Poliomyelitis – Fever, diarrhea, backache, sore throat, aches in limbs; can infect spinal
chord and cause paralysis and muscle weakness
Parasitic Protozoa Amoebic dysentery – Severe diarrhea, headache, abdominal pain, chills, fever; if not
treated can cause liver abscess, bowel perforation, and death
Giardiasis – Diarrhea, abdominal cramps, flatulence, belching, fatigue
Cryptosporidum – Severe diarrhea, cramps for up to 3 weeks, and possible death for
people with weakened immune system
Parasitic Worms
Schistosomiasis – Abdominal pain, skin rash, anemia, chronic fatigue, and chronic general
ill health
Ancylostomiasis – Severe anemia and possible symptoms of bronchial infection
Testing Water for Pollutants
• Escherichia coli (E. coli) – lives in the colons of humans and other
animals and is present in fecal waste. Most coliform bacteria do not
cause disease but E. coli O157:H7 is pathogenic and very dangerous.
• Presence of coliforms in water indicates exposure to human or animal
wastes that are likely to contain disease causing agents.
• To be safe for drinking 100 mL of water should contain no colonies of
coliform bacteria. To be safe for swimming 100 mL of water should
contain no more than 200 colonies of coliform bacteria. By contrast a
raw sewage sample may contain several million coliform bacteria
colonies.
Testing Water for Pollutants
• Dissolved Oxygen (DO) – measured in ppm (parts per million). 1 ppm
is equivalent to 1 mg/L or 1 mg/kg of water or soil respectively.
• Excessive inputs of oxygen-demanding wastes can deplete DO levels.
• DO values for water quality at 20◦ C.
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Good – 8 to 9 ppm
Slightly Polluted – 6.7 to 8 ppm
Moderately Polluted – 4.5 – 6.7 ppm
Heavily Polluted – 4 to 4.5 ppm
Gravely Polluted – below 4 ppm
Testing Water for Pollutants
• Chemical Analysis – identify specific organic/inorganic chemicals in
polluted water.
• Organic chemicals:
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VOC’s and PCB’s
Pharmaceutical drugs
Detergents
Petroleum Products
• Inorganic
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Acidity (pH/alkalinity)
Ammonia
Heavy Metals (Pb, Hg etc.)
Sediment ( turbidity, conductivity)
Fertilizers (nitrates and phosphates)
Testing Water for Pollutants
• Indicator Species – use of cattails and other aquatic plants from
polluted water areas and analyze toxins found in tissues. Use of
benthic species such as mussels.
• Amphibians and Dragonflies are great indicator species due to their
amphibious lifestyles.
Genetic engineers are working
to develop bacteria and yeast
that glow in the presence of
specific pollutants.
Testing Water for Pollutants
• Water Quality Parameters
• Temperature, pH, DO, Conductivity, Turbidity, Chlorophyll-A, Stream Flow,
Total solids, alkalinity, fecal coliform, phosphates and nitrates
• These parameters are mainly for surface water monitoring.
• Agencies and volunteers can utilize test kits to monitor these
parameters.
• These parameters provide crucial data for developing conservation
and pollution remediation efforts.
Major Water Pollution Problems in
Streams and lakes
• Streams can recover rapidly from moderate levels of degradable, oxygendemanding wastes through dilution and biodegradation.
• This natural process will not occur when streams are overloaded with
pollutants, dammed up, or flow is reduced.
• This process cannot remove slowly degradable and nondegradable
pollutants.
• The breakdown of biodegradable wastes by bacteria depletes DO and
creates an oxygen sag curve.
• BOD – Biochemical Oxygen Demand; the amount of DO required by
aerobic biological organisms to break down organic material in a given
water sample at a certain temperature over a specific time.
Stream Pollution
Developed vs Developing Countries
Developed
Developing
• Legislation (US)
(Clean Water Act 1972)
• Set standards for wastewater from
industry
• Use of waste water treatment
plants
• Clean up of Cuyahoga River in Ohio
• Clean up of Thames River in
England
• Half of the world’s 500 rivers are heavily
polluted.
• Cannot afford wastewater treatment
• Lack proper legislation
• 80-90% of untreated sewage discharged
directly into rivers is then used for drinking,
bathing, and washing clothes
• More than 2/3 of India’s water sources are
polluted with industrial waste and sewage.
• 1/3 of the monitored rivers in China are
judged unfit for agricultural and industrial
use.
India’s Ganges River
• Ganges is considered a Holy River
• Hindu culture believes in cremation and disposing of the ashes into the
river to allow the soul to get to heaven.
• Large quantities of wood are used for cremations causing air pollution and
deforestation.
• The river is polluted with human corpses because many people cannot
afford cremations and dispose of unburned and partially burned corpses.
• The river is polluted with livestock carcasses as well
• People bathe, drink, and take dips for religious reasons
• Another religious custom involves throwing vividly painted statues into the
river. These paints often have toxic metals and potentially harmful organic
compounds in them.
Lake and Reservoir Pollution
• Lakes and reservoir are less effective at diluting pollutants than
streams because they have stratified layers and have little to no flow.
• The flushing and changing of water in lakes and reservoirs can take 1
to 100 years, compared to several days or weeks for a stream.
• They are more vulnerable to contamination by runoff pollutants and
nondegradable toxic substances like lead, mercury, and selenium.
• These contaminants kill benthic life, fish, and birds that feed on
contaminated aquatic organsims.
• Many toxic chemicals and acids enter lakes and reservoirs from the
atmosphere.
Eutrophication
Groundwater and Drinking water Pollution
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Groundwater cannot clean itself very well.
95% of drinking water in the rural US comes from groundwater.
Common pollutants are fertilizers, pesticides, gasoline, and organic solvents.
People who dump or spill fuel and solvents also pollute groundwater.
Once groundwater becomes contaminated it becomes difficult and costly to
remediate because the pollutants become embedded in the porous layers of
sand, rock, and gravel.
• The slow moving groundwater disperses the pollutant in a widening plume of
contamination. This prevents dilution and the cold temperature of the water
reduces chemical reactions that decompose waste.
• Takes decades to thousands of years to cleanse groundwater of slowly degradable
and nondegradable wastes.
Groundwater Pollution is a Serious
Threat
US EPA survery of 26,000 industrial
waste lagoons revealed 1/3 of them
did not have a protective liner.
Almost 2/3 of America’s liquid
hazardous wastes are injected into
deep disposal wells underground.
By 2006, EPA completed the cleanup of
350,000 of more than 460,000
underground tanks in the US.
Determining the extent of a leak can
cost $25,000 – 250,000 and clean up
can cost $10,000 – more than 250,000.
MTBE (Methyl Tertiary Butyl Ether), a
gas additive used since 1979 is another
major threat to groundwater sources.
By the time this was discovered, more
than 250,000 leaking tanks had
contaminated aquifers.
Arsenic Contamination
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Soils and Rocks naturally contain arsenic.
Mining and Ore Processing can release arsenic into drinking water.
Accepted safe drinking standards are 10 ppb (parts per billion).
2007 WHO study found that more than 140 million people in 70 countries are
drinking water with arsenic concentrations 5-100 times that level.
Bangladesh, China, and West Bengal (state in India) suffer from high levels of
arsenic.
Exposure can cause skin, bladder, and lung cancer. (Chile had 3-14 times higher
than normal rates)
Many EPA scientists want to lower the standard to 3-5 ppb due to the cancer rate
being 30 times higher than any other carcinogen regulated by the EPA.
Rice University in Houston, Texas had a break through in 2006 for a relatively
cheap means to treat water for arsenic using a rust powder in nanocrystal form.
Pollution Prevention is the only effective way
to protect Groundwater.
Prevention
Cleanup
• Find substitutes for toxic chemicals.
• Keep toxic chemicals out of the
environment.
• Install monitoring wells near landfills and
underground tanks
• Require leak detectors on underground
tanks
• Ban hazardous waste disposal in landfills
and injection wells
• Store harmful liquids in aboveground
tanks with leak detection and collection
systems.
• Pump to surface,clean, and return
to aquifer
(very expensive)
• Inject microorganisms to clean up
contamination
(less expensive but still costly)
• Pump nanoparticles of inorganic
compounds to remove pollutants
(still being developed)
Purifying Drinking Water
• Use of reservoirs and purification plants
• Protecting Watersheds (New York saved billions by restoration)
• Processing sewer water into drinking water (El Paso, Texas – 40%)
• Fill plastic bottles with water and expose to intense sunlight can kill
microbes in as little as 3 hours. Paint one side black to improve solar
disinfection.
• Use of nanofilters to clean contaminated water. (Life Straw)
Laws to Protect Drinking Water Quality
• Clean Water Act of 1972 set wastewater standards for industry
• Clean Drinking water Act of 1974 established maximum contaminant
levels.
• UN estimates 5.6 million Americans drink water that does not meet
EPA standards.
• Health scientist want to connect smaller treatment stations with
larger ones and ban lead in all faucets, plumbing pipes, and fixtures.
• Water-polluting industries petition for exemptions from following EPA
regulations due to expensive technologies.
Bottle Water
• Between 1976 and 2006 bottled water consumption increased from 2 gallons to 30
gallons a year.
• Bottled water costs 240- 100,000 times more than tap water.
• Studies indicate that ¼ of it is tap water in a bottle, and that 40% of it is contaminated
with bacteria and fungi.
• Government testing standards for bottled water are not as high as they are for tap water.
• Consumers spend $100 billion on bottled water (US 1-2 billion)
• Plastic water bottles pollute the earth enough to circle the equator 8 times end to end.
• Pollution of air from manufacturing water bottles and shipping them is extensive.
• The oil used to produce 30 billion water bottles used in the US could fuel 100,000 cars for
a year.
• The energy used to pump, process, transport and refrigerate the water would be enough
to run 3 million cars for a year.
Ocean Pollution
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Coastal areas bear the brunt of inputs of pollutants and waste.
40% of world’s population lives on or near the coast.
53% of US population lives on or near the coast.
80-90% of municipal sewage from developing countries is dumped into the oceans untreated.
Of the world’s 15 largest metropolitan areas, 14 are near coastal waters.
Cruise ships pollute heavily
In 2005 EPA classified four of five estuaries as threatened or impaired
Runoffs of sewage and agricultural wastes introduce large quantities of phosphates and nitrates
which cause harmful alga blooms (red tide)
Harmful algal blooms cause oxygen-depleted zones. (Gulf of Mexico)
Ocean oil (crude and refined petroleum) from tankers and offshore drilling rigs
37% -and perhaps even half – of the oil reaching the oceans is waste oil, dumped, spilled, or
leaked onto land or into sewers.
Have reduced incidents from tanker accidents by 75% and oil discharges from industry and cities
by 90%
Ocean Oil and Wildlife
• Volatile organic hydrocarbons in oil immediately kill many aquatic organisms,
especially in their vulnerable larval forms.
• Tar-like globs that float on the surface can coat feathers and fur destroying
animals buoyancy and insulation.
• Heavy oil components that sink to the ocean floor or wash into estuaries can
smother bottom-dwelling organisms, or make them unfit for consumption.
• Some oil spills have killed coral reefs and fish populations
• Research shows that ecosystems can recover from crude oil spills in about 3
years, but exposure to refined oil can take up to 10-20 years, especially in
estuaries and salt marshes
• Scientists estimate that current cleanup methods can only recover approximately
15% of the oil from a major spill.
• Prevention of oil pollution is the most effective and least costly approach
Coastal Water Pollution
Solutions
Prevention
Cleanup
• Reduce input of toxic pollutants
• Separate sewage and storm lines
• Ban dumping of wastes and
sewage by ships in coastal waters
• Ban ocean dumping of sludge and
hazardous dredged material.
• Regulate coastal development, oil
drilling, and oil shipping.
• Require double hulls for oil tankers
• Improve oil spill clean-up
capabilities.
• Use nanoparticles on sewage and
oil spills to dissolve the oil or
sewage (still under development)
• Require Secondary treatment of
coastal sewage
• Use wetlands, solar-aquatic or
other methods to treat sewage.
Reducing Water Pollution
Reduce surface water from nonpoint sources
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Farmers keeping fields covered vegetation.
Organic farming opposed to fertilizer farming.
If fertilizer farming use slow release fertilizers.
Use buffer zones of vegetation and keeping feedlots and animal wastes sites
away from water sources.
• Applying pesticides only when needed and relying more on integrated pest
management plans.
• Tougher pollution control regulations for US livestock operations
Reducing Point Source Pollution
• Clean Water Act 1972 led to significant improvements.
• Between 1992 and 2002 community water systems that met health standards
improved from 79% to 94%.
• The percentage of US stream lengths found to be fishable and swimmable increased
from 36% to 60%.
• The amount of topsoil lost to agricultural run off was reduced by 1.1 billion metric
tons (1 billion tons).
• The US population served by sewer water treatment increased from 32% to 74%.
• Annual wetland losses decreased by 80%.
But. . .
In 2006 EPA found 45% of the countries lakes and 40% of the countries streams were
still too polluted for swimming and fishing and that run off of animal wastes pollutes 7
of every 10 US rivers.
Sewage Treatment Reduces Water Pollution
• Sewage treatment prevents some but not all wastes from going down
stream.
• There are three steps:
• Primary – physical removal of waste (screens and settling out)
• Secondary – biological removal of waste (microbes)
• Tertiary – specialized physical and chemical removal of waste (special filters)
Village Creek Water Reclamation Facility
• Fort Worth’s waste water treatment facility
• Influent Flow = 100 million gallons
• Screenings = 13 cubic yards
• Effluent = 94 million gallons
• Reclaim water flow = 6 million gallons
• Land applied biosolids = 80 dry tons
• Power generated = 5 MW
• Power saved by heat recovery = 1.5 MW
• Power purchased = 2 MW
SCREENS
Trash removed
COLLECTION SYSTEM
Collect waste and transport to treatment plan
PRIMARY CLARIFIER
Solids settle by gravity
AERATION BASIN
Organic material
consumed by bacteria
ANAEROBIC DIGESTER
Solids stabilized by
bacteria
SECONDARY CLARIFIER
Solids settle by gravity
DEWATERING
Excess water removed
from sludge
FILTERS
Remaining solids filtered
out
DISINFECTION
Pathogens destroyed by
chlorination
DECHLORINATION
Remaining chlorine
removed by sulfur dioxide
LAND APPLICATION
Biosolids distributed on
ranch land
GAS TURBINES
Biogas used to run
turbines
POWER
GENERATION
Electricity produced
by generator
DISCHARGE
Effluent release to Trinity River
RECLAMATION
Reused for irrigation and cooling water
HEAT RECOVERY
Heat digesters,
building, run steam
engine
The Composting Toilet
• Less materials and fewer pipes.
• No water to very low water use.
• Breakdown human waste into
useful fertilizers that are
pathogen free.
• Oxygen, moisture, and heat are
key to keeping an odor free
operation.
How can this device help to prevent
water pollution?
Treating Sewage by Working with Nature
Solutions to Water Pollution
• Prevent groundwater contamination
• Reduce nonpoint runoff
• Reuse treated wastewater for irrigation
• Find substitutes for toxic pollutants
• Work with nature to treat sewage
• Practice the three R’s of resource (reduce, reuse, recycle)
• Reduce Air Pollution
• Reduce Poverty
• Slow population growth
What YOU can do to reduce Water Pollution
• Fertilize garden and yard plants with manure or compost instead of
commercial or inorganic fertilizers.
• Minimize your use of pesticides, especially near bodies of water.
• Prevent yard wastes from entering storm drains.
• Do not use water fresheners in toilets
• Do not flush unwanted medicines down the toilet
• Do not pour pesticides, paints, solvents, oil, antifreeze, or other
products containing harmful chemicals down the drain or onto the
ground.