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Pollution
Overview
Point and Nonpoint Sources of Pollution
Point & Nonpoint Sources of Pollution:
1. Point sources account for 60% of the water pollution in the
USA today.
2. Oil spills and dumping are a form of point source pollution
and do create major problems in today’s world.
3. Nonpoint sources of water pollution often come from
flooding of surrounding lands around the streams and rivers.
The built up pollution of oil, pesticides and wastes are
suddenly washed into the water system. Look at Cadillac
Heights and the Trinity River system.
Types of Water Pollutants
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Pathogens
Organic Wastes
Chemical
Sediments
Nutrients
In the Ganges River in India the
people drink, wash clothes and
use the restroom all in the same
water.
Pathogens
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Disease-causing agents (see next
slide)
Safety measures
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purification of public water supply
sanitary collection/treatment of sewage
sanitary practices when processing food
Common
Water
Pathogens
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Just hope that
you don’t
become
personally
acquainted
with them !
Colliform Bacteria Culture
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Colliform bacteria come from animal
wastes and will poison you.
Filter water and grow the culture.
Organic Wastes
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Dissolved oxygen (DO) in the water is
depleted during decomposition of
organic wastes.
Water quality test.
 Biochemical oxygen demand
(BOD): measure of the amount of
organic material.
Chemical Pollutants
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Inorganic chemicals
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Heavy metals, acids, road
salts
Organic chemicals
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Petroleum, pesticides,
detergents
Effect of Sediments on Stream
Ecology
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Loss of hiding-resting places for small
fish.
Attached aquatic organisms scoured
from the rocks and sand.
Poor light penetration
Aquatic Plant Life
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Benthic plants
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Emergent vegetation
Submerged aquatic vegetation (SAV’s)
Phytoplankton
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Green filamentous and single cell
Bluegreen single cell
Diatoms single cell
Nutrient Enrichment
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Oligotrophic: nutrient-poor water
Eutrophic: nutrient-rich water
What kind of plants would dominate in
oligotrophic and eutrophic conditions?
Oligotrophic
Conditions
Changing to
Eutrophic
Eutrophication
Oligotrophic
Eutrophic
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As nutrients are
added from
pollution, an
oligotrophic
condition rapidly
becomes
eutrophic.
Eutrophic or Oligotrophic?
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High dissolved O2
Deep light penetration
High phytoplankton
Eutrophic or Oligotrophic?
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Turbid waters
High species diversity
Good recreational qualities
High detritus decomposition
Eutrophic or Oligotrophic?
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Low bacteria decomposition
Benthic plants
Warm water
High nutrient concentration
BOD
High sediments
Natural Vs. Cultural Eutrophication
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Natural eutrophication
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aquatic succession
occurs over several hundreds of years
Cultural eutrophication
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driven by human activities
occurs rapidly
Combating Eutrophication
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Attack the symptoms
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Chemical treatment
Aeration
Harvesting aquatic weeds
Drawing water down
Combating Eutrophication
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Getting at root cause
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Controlling point sources
Controlling nonpoint sources
Controlling Point Sources
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Ban phosphate detergents
Sewage-treatment improvements
Controlling Nonpoint Sources
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Difficult to address runoff pollutants
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Urban
Agricultural fields
Deforested woodlands
Overgrazed pastures
Best Management Practices (BMP)
Collecting Ponds
Raw Sewage
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99.9% water to 0.1% waste
Pollutants in sewage are:
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Debris and grit
Particulate organic material
Colloidal and dissolved organic
material
Dissolved inorganic material
Water Treatment System
Water Pollutants and Trying to Copy
Nature’s Water Filters
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Major sources of water pollution
Eutrophication: causes and cures
Human sewage management: a
pollutant of “amount” and “type”.
Water Stewardship Working Together
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Louisiana Wetlands Conservation and
Restoration Trust Fund
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$1.5 billion to restore
LA wetlands
Wally Water Drop Explains:
Waste Water Treatment Plant
http://vimeo.com/1973831
Control/ Click here
 Processes explained here
 Compare to diagram in text book
Miller 16 Fig 20-19 & to diagrams in
this ppt
Sewage Treatment
Match Technology With Removal
Function
Technology
Primary Treatment:
Physical
Bar Screen
Grit Screen
Secondary Treatment:
Biological
Removal Function
Large or small debris
Trash & Particulate
organics
Grit (sand, silt) &
Biological
Biological Nutrient Removal
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Activated sludge: 3 zones
Conversion of NH4 to NO3
NO3 converted to N gas and released
PO4 taken up by bacteria and released
with excess sludge
Biological Nutrient Removal
Sludge Treatment
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Anaerobic digestion
Composting
Pasteurization
Alternative Treatment Systems
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Individual septic systems
Wetland-based wastewater treatment
Wastewater effluent irrigation
Reconstructed wetland systems
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Beaumont, TX
Composting toilet
Septic Tank Treatment
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Aerobic digestion
of solids in septic
tank.
Flow of liquids
into drain field for
evaporation,
infiltration, or
irrigation.
Legislation of Water Pollution:
The Clean Water Act.
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First passed in 1972 as a federal program to
protect and restore the physical , chemical and
biological integrity of the nation’s waters. It
established the first water quality standards.
EPA is the controlling agency.
Requires permits for discharge of pollution.
Encouraged better pollution control technology
through fees, fines and tax reduction.
Water Quality Act: 1987
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An amendment to the Clean Water Act
that
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created a loan fund for construction of
water treatment plants.
Addresses regional water shed pollution
Addresses nonpoint source pollution.
Success of Water Treatment :
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Some success of the Clean Water Act (as of
2002):
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The number of people in the USA with adequate
sewage treatment plants has risen from 85 million
to 173 million people.
Soil erosion has reduced by 1 billion tons/year.
66% of the USA waterways are safe for swimming
and fishing. (Doubled since 1972).
Chesapeake Bay bottom vegetation has increased
by 70% since 1972.