Learn Environmental Science

1. Lesson 3:
Water Resources and
Water Pollution

2. c o n t e n t
Ground and Surface Water
1
Water Usage
2
Water Pollution
3
Water Treatment
4

3. Lesson Objectives:
• Describe the properties and uses of ground and surface waters;
• List and identify ways to conserve water;
• Describe the impacts that oil has on marine life;
• Explain what a septic system is and the processes involving
wastewater treatment;

4. Ground and
Surface Water
01

5. Surface Water
• Surface water is any body of water
found on the Earth’s surface,
including both the saltwater in the
ocean and the freshwater in rivers,
streams, and lakes.
• Precipitation and water runoff feed
bodies of surface water.
• Evaporation and seepage of water
into the ground, on the other hand,
cause water bodies to lose water.

6. Types of Surface Water

7. Groundwater
• It is the water that seeps deep into
the ground.
• It comes from saturated zones of roc
and soil, known as aquifers beneath
the Earth’s surface. It can be
accessed by digging well or using
motors.
• It is the main source of drinking
water supplies.

8. Uses of Groundwater Uses of Surface Water
• Drinking water
• Crop Irrigation
• Industries
• Mining
• Generate electricity
• Drinking water
• Crop irrigation
• Recreation
• Manufacturing/Industries

9. Two sources of pollution in groundwater
Point Sources Non-Point Sources
✓ Localized and easily
identifiable
✓ Includes landfills,
underground gas/oil tanks,
septic tanks, industrial
sources, and accidental spills
✓ Include nutrient run-off such
as pesticides that can enter
the sediment and soil from
agricultural operations.

10. Water Usage
02

12. Water
Pollution
03

13. Marine pollution
• Marine pollution is a combination of chemicals
and trash, most of which comes from land sources
and is washed or blown into the ocean.
• This pollution results in damage to the
environment, to the health of all organisms, and
to economic structures worldwide.

14. Eutrophication
• The process by which the entire body of water, or parts of it, becomes
progressively enriched with minerals and nutrients, particularly nitrogen and
phosphorus.
• Algal bloom result of eutrophication in which there is a rapid increase of algae
in freshwater or marine water systems.

15. Taken from orbit in October 2011, the worst algae bloom that Lake Erie has experienced in decades.
Record torrential spring rains washed fertilizer into the lake, promoting the growth of microcystin-
producing cyanobacteria blooms.

16. Two main types of Water Pollution
Chemical
contamination Marine Trash
Occurs when human activities, notably
the use of fertilizer on farms, lead to
the runoff of chemicals into waterways
that ultimately flow into the ocean.
Encompasses all
manufactured products-most
of them plastics-that end up in
the ocean.

17. Water
Treatment
04

18. Water Treatment
• Any process that improves the quality of water to make appropriate
for a specific end-use. The end-use may be drinking, industrial water
supply, irrigation, river flow maintenance, water recreation or many
other uses.
• Water treatment removes contaminants and undesirable
components, or reduces their concentration so that the water
becomes fit for its desired end-use.

19. Processes involved in Water Treatment
• Physical processes such as settling and filtration.
• Chemical processes such as disinfection and coagulation.
• Biological processes such as slow sand filtration.

20. Water Treatment Steps
Step 1 (Screening and Pumping) –
incoming wastewater passes through
screening equipment where objects are
removed. The material removed is disposed in
a landfill.
Step 2 (Grit Removal) – heavy but fine
material such as sand and gravel is removed
from the wastewater.

21. Water Treatment Steps
Step 3 (Primary Settling) - The material, which will settle, but
at a slower rate than step two, is taken out using large circular
tanks called clarifiers. The settled material, called primary
sludge, is pumped off the bottom and the wastewater exits the
tank from the top.
Floating debris such as grease is skimmed off the top
and sent with the settled material to digesters. In
this step, chemicals are also added to remove
phosphorus.

22. Water Treatment Steps
Step 4: Aeration / Activated Sludge
• In this step, the wastewater receives most of its treatment.
Through biological degradation, the pollutants are consumed by
microorganisms and transformed into cell tissue, water, and
nitrogen. The biological activity occurring in this step is very
similar to what occurs at the bottom of lakes and
rivers, but in these areas the degradation takes
years to accomplish.

23. Water Treatment Steps
Step 5: Secondary Settling
• Large circular tanks called secondary clarifiers allow the treated
wastewater to separate from the biology from the aeration tanks at
this step, yielding an effluent, which is now over 90% treated. The
biology (activated sludge) is continuously pumped from the
bottom of the clarifiers and returned to the aeration tanks in step
four.

24. Water Treatment Steps
Step 6: Filtration
• The clarified effluent is polished in this step by filtering
through 10 micron polyester media. The material captured
on the surface of the disc filters is periodically backwashed
and returned to the head of the plant for treatment.

25. Water Treatment Steps
Step 7: Disinfection
• To assure the treated wastewater is
virtually free of bacteria, ultraviolet
disinfection is used after the filtration
step. The ultraviolet treatment process
kills remaining bacteria to levels within
our discharge permit.

26. Water Treatment Steps
Step 8: Oxygen Uptake
• The treated water, now in a very stabilized high quality state, is
aerated if necessary to bring the dissolved oxygen up to permit
level.

28. What is a Septic Tank?
A septic tank is an underground chamber
made of concrete, fiberglass, or plastic
through which domestic wastewater
(sewage) flows for basic sewage treatment.

29. What is a Septic Tank?
• Settling and anaerobic digestion processes reduce solids and
organics.
• Septic tank system are a type of simple onsite sewage facility.
• The term “septic” refers to the anaerobic bacterial
environment that develops in the tank that decomposes or
mineralizes the waste discharge into the tank.

30. How does a septic system works?

31. Thank you!☺