Water Pollution

1
Water Pollution
2
Global Population and Water
3
Water Pollution

• Pollution
• The degradation of physical, chemical or
  biological properties of water beyond normal
  conditions.
• Major classes of water pollutants
• Chemicals
• Nutrients and Sediments
• Biological
• Radiological.

4
Categories of Sources of Water Pollution

• Point Source
• Non-Point Source

5
Point vs. Non-Point Sources
6
Point-Source to GW
7
Sources of Chemicals in US Surface Waters
8
Sources of Chemicals in US Surface Waters
9
Major Classes of Pollutants

• Chemicals
• Metals Mercury, Cadmium, Copper, Lead
• Synthetic organics Pesticides, PCBs, Oil
• Physical alterations
• Suspended solids
• Thermal

10
Chemical Pollutant Examples
11
Chemical Pollutant Examples
12
Chemical Pollutant Examples
13
Acid Mine Drainage

• Water with a high concentration of sulfuric acid
  that drains from mines
• Serious water pollution problem
• Damages aquatic ecosystems, pollutes bodies of
  water and degrades water quality

14
Physical Pollution Suspended Solids
15
Thermal Pollution
16
Major Classes of Pollutants

• Nutrients
• Phosphorus and nitrogen
• Biological
• Pathogens
• Exotic species
• Radioactive materials

17
Exotic Species
18
Biochemical Oxygen Demand

• The amount of oxygen required for biochemical
  decomposition process
• 3 zones
• A pollution zone
• An active decomposition zone
• A recovery zone

19
3 Zones Example
20
Biological Oxygen Demand and Dissolved Oxygen

• BOD and DO are not pollutants but are critical
  aspects of water quality.
• Oxygen usage by aquatic organisms can be reported
  as BOD.
• DO is the amount of dissolved oxygen available in
  the water column.
• As BOD increases, DO decreases.

21
BOD problems result from any input of organic
matter that can decay

• Livestock manure
• Industry

22
(No Transcript)
23
(No Transcript)
24
Cultural Eutrophication

• Process by which human impacts speed-up the
  natural process of eutrophication in a body of
  water.
• Input of nitrogen and phosphorus.

25
Nutrient Sources
26
Nutrient Source
27
Progression of Cultural Eutrophication

• Increased nutrients into waterway.
• Increased plant growth.
• Increased organic matter
• Higher sedimentation
• More food for decomposers.
• Increased BOD.
• Decreased DO/light penetration.

28
Oligotrophic vs. Eutrophic
29
Cultural Eutrophication
30
Municipal Wastewater Treatment
31
Municipal Wastewater Treatment

• Pretreatment Use of screens to remove large
  debris entering the facility.
• Slows down the flow of raw sewage to allow grit
  to settle in the grit chamber.

32
Pretreatment
33
Municipal Wastewater Treatment

• Primary Treatment use of sedimentation tanks to
  slow flow so that suspended solids or
  particulates can settle to the bottom for removal
  to a sludge thickener.
• Floating objects are skimmed off the top for
  disposal.

34
Primary Treatment
35
Municipal Wastewater Treatment

• Secondary treatment Biological removal of
  organic nutrients in suspension Reduces BOD.
• Uses organisms of the detritus/decomposer family.
• Relies on aerobic respiration to convert organic
  material to carbon dioxide and water.
• Removes some nutrients.

36
Secondary Treatment
37
Tertiary Treatment

• Specific treatments used to remove pollutants
  that still remain after treatment.
• Technologies are expensive and rarely used.

38
Septic Tank Disposal Systems
39
Wastewater Renovation and Conservation Cycle

• Steps
• 1. Return of treated wastewater to crops
• 2. Renovation or natural purification by slow
  percolation of the wastewater into soil to
  eventually recharge the groundwater resource with
  clean water
• 3. Reuse of the treated water

40
(No Transcript)
41
(No Transcript)
42
(No Transcript)
43
Approaches of Water Pollution Control

• Clean Water Act of 1972
• Safe Drinking Water Act
• Public education
• Funding of wastewater treatment plants
• Industrial Pretreatment