2. DEFINITION
A change in the chemical, physical,
biological and radiological quality of
water that is injurious to its existing,
intended or potential use
3. Where do Water pollutants come from?
Point Sources – A single definable source
of the pollution, e.g. a factory, a sewage
plant, etc. Point-source pollution is usually
monitored and regulated.
4. Non-point sources – is not a single source,
but a wide range of sources, e.g. runoff from
urban areas, or farmland. Non-point
sources are much more difficult to monitor
and control
Where do Water
pollutants come from?
6. Pollution of Water
1. Industrial pollution
2. Surface pollution
3. Groundwater
contamination
4. Sewage pollution
5.Oil pollution
6.Thermal pollution
7. Water pollutants
Industrial Effluents
This waste water may contain acids, alkalis, salts, poisons,
oils and in some cases harmful bacteria.
Mining and Agricultural Wastes
Mines, especially gold and coal mines, are responsible for
large quantities of acid water.
Agricultural pesticides, fertilizers and herbicides
may wash into rivers and stagnant water bodies.
Sewage Disposal and Domestic Wastes
Sewage as well as domestic and farm wastes often pollute
rivers and dams.
9. Non-persistent (degradable)
water pollutants
These compounds can be broken down
by chemical reactions or by natural
bacteria into simple, non-polluting
substances such as carbon dioxide and
nitrogen.
if the pollution load is high, this process
can lead to low oxygen levels and
eutrophication.
This damage is reversible.
11. Persistent Water pollutants
This is the most rapidly growing type of
pollution
This includes substances that degrade very
slowly or cannot be broken down at all;
They may remain in the aquatic environment
for years or longer periods of time.
The damage they cause is either irreversible
or repairable only over decades or centuries
12. Persistent Water pollutants
some pesticides (e.g., DDT, dieldrin)
petroleum and petroleum products
PCBs, dioxins, polyaromatic hydrocarbons
(PAHs)
radioactive materials such as strontium-90,
cesium-137, radium-226, and uranium
metals such as lead, mercury, cadmium
13. Other water quality pollutants
warm water from cooling towers
(thermal pollution)
floating debris
garbage
foam
14. 1. Classes of Water
pollutants
Pathogens Bacteria, Viruses, Protozoa,
Parasitic Worms, Colliform Bacteria Used As
Indicators Of Water Quality
Oxygen Demanding Wastes Organics That Are
Decomposed By Bacteria And That Use A Lot Of
O2, Dissolved Oxygen (DO) Decreases, And BOD
Increases
Water Soluble Inorganic Chemicals Acids,
Salts, Toxic Metal Compounds Like Mercury, And
Lead.
Inorganic Plant Nutrients Water Soluble
Phosphates, Nitrates => Algal Blooms, Decreased
Dissolved O2, Increased BOD.
15. 2. Classes of Water
pollutants
Organic Chemicals Oil, Gas, Plastics, Pesticides, Cleaning
Solvents, Detergents, Etc.
Radioactive Isotopes Are Biologically Amplified To Higher
Concentrations In The Food Chain.
Ionizing Radiation cause Birth Defects, Cancer.
Warmed Water From Power Plants.
Decreases DO And Increases Susceptibility To Diseases.
16. Industrial Water
pollution
Industries discharge a variety of
pollutants in their wastewater including
heavy metals , resin pellets, organic
toxins, oils, nutrients, and solids.
17. Over 1 billion people lack access to
safe water supplies, while 2.6 billion
people lack adequate sanitation. This
has led to widespread microbial
contamination of drinking water.
Water-associated infectious diseases
claim up to 3.2 million lives each year,
approximately 6% of all deaths
globally.
Microbial contaminationMicrobial contamination of water
18. Acid rain
Acid rain is formed when moisture in the
clouds mixes with sulfur or nitrogen in the
air.
The sulfur and nitrogen get into the air by
the burning of fossil fuels such as coal
and gasoline. The average pH of rainfall is
4.3.
21. Disease burden from water pollution
Water-associated infectious diseases
claim up to 3.2 million lives each year,
approximately 6% of all deaths
globally.
The burden of disease from
inadequate water, sanitation, and
hygiene totals 1.8 million deaths and
the loss of greater than 75 million
healthy life years.
22. Oil Pollution of water
Both Point and Nonpoint Sources
Largest source of oil pollution is pipeline
leaks and runoff
–61% ocean oil pollution river & urban
runoff
–30% intentional discharges from
tankers
–5% accidental spills from tankers
23. CONTROL OF WATER
POLLUTION
Nonpoint Pollution Sources and Land
Management
–Reduce nutrient loading through land
use regulations
–Source reduction is cheapest and
most effective way to reduce
pollution.
Banning phosphate detergents
Soil Conservation
Sewage Treatment
Remediation
25. MUNICIPAL SEWAGE
TREATMENT
Primary Treatment - Physical separation of large
solids from the waste stream.
Secondary Treatment - Biological degradation of
dissolved organic compounds.
– Effluent from primary treatment transferred into
trickling bed, or aeration tank
Effluent from secondary treatment is usually disinfected
(chlorinated) before release into nearby waterway.
Tertiary Treatment - Removal of plant nutrients
(nitrates and phosphates) from secondary effluent.
– Chemicals, or natural wetlands.
26. Water Remediation
Extraction techniques are used to pump
out polluted water for treatment.
–Oxidation, reduction, neutralization,
or precipitation.
Living organisms can also be used
effectively to break down polluted
waters.
27. Solutions on Water Pollution
•Prevent groundwater contamination
•Greatly reduce nonpoint runoff
•Reuse treated wastewater for irrigation
•Find substitutes for toxic pollutants
•Reduce resource waste
•Reduce air pollution
•Reduce poverty
