Recycling-of-Wate lesson on earth science r.pdf

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1. RECYCLING
OF WATER

2. WATER RECYCLING IS REUSING TREATED
WASTEWATER FOR BENEFICIAL PURPOSES
(SUCH AS AGRICULTURAL AND LANDSCAPE
IRRIGATION, INDUSTRIAL PROCESSES, TOILET
FLUSHING, AND REPLENISHING A GROUND WATER
BASIN, REFERRED TO AS GROUND WATER
RECHARGE)

3. USES OF RECYCLED
WATER
• Agriculture
• Landscape
• Public parks
• Golf course irrigation
• Cooling water for power
plants and oil refineries

4. USES OF RECYCLED
WATER
• Processing water for mills/ plants
• Toilet flushing
• Dust control
• Construction activities
• Concrete mixing
• Artificial lakes

5. Decreases
Discharge to
Sensitive Water
Bodies
Can Decrease
Diversion of
Freshwater from
Sensitive
Ecosystems
BENEFITS OF
RECYCLING WATER

6. Used to Create or
Enhance Wetlands
and Riparian (Stream)
Habitats
Reduce and
Prevent Pollution
BENEFITS OF
RECYCLING WATER

7. 1.
PROCESSES OF RECYCLING
WATER
2. 3. 4.
Taking the
water away
Screening
process
Primary
Treatment
Secondary
Treatment

8. 5.
PROCESSES OF RECYCLING
WATER
6. 7.
Final
Treatment
Sludge
Treatment
Back to the
river

9. TAKING THE
WATER AWAY
SCREENING
PROCESS
• The wastewater goes down
the drain and into a pipe,
which takes it to a larger
sewer pipe under the road.
• The sewer joins an
underground network of other
sewers.
• Remove of large objects that
may block or damage
equipment
- wipes, sanitary items and
cotton buds also some bottles
• Wastewater often contains a
lot of grit that gets washed
into the sewer, so an
equipment is used to remove
this

10. PRIMARY
TREATMENT
• The wastewater still contains
various waste
- separation of waste from the
water
- wastewater is put into large
settlement tanks, which cause
solids to sink to the bottom
•In a circular tank, large arms, or
scrapers, slowly move around the
tank and push the sludge towards
the centre where it is then
pumped away for further
treatment.
•The water passes over a wall near
the top of the tank and is taken to
the next stage of the treatment
process.

11. SECONDARY
TREATMENT
FINAL
TREATMENT
• In larger sewage treatment
works, the wastewater is put
into rectangular tanks called
‘aeration lanes’, where air is
pumped into the wastewater.
• The treated wastewater is
passed through a final
settlement tank, where the
good bacteria sinks to the
bottom.
• The treated wastewater is
slowly filtered through a bed of
sand, which acts as a filter and
catches any remaining
particles.

12. SLUDGE
TREATMENT
• The sludge collected at the start of
the process is treated:
- combined heat and power
It treats the sludge using ‘anaerobic
digestion’. This is where the sludge
is heated to encourage the bacteria
to eat it. This creates biogas that we
then burn to create heat, which in
turn creates electricity.
•Gas to grid
We can also clean the biogas to a
higher standard (biomethane) so
that we can put it into the national
gas grid.
•Thermal destruction
Involves drying the sludge into
blocks called ‘cake’, which are then
burned to generate heat. We capture
this heat and turn it into electricity.

13. BACK TO THE
RIVER
• It can be returned to local rivers
and streams. In some areas, the
water put back into the river is very
important as it helps to keep them
healthy. The quality of the cleaned
wastewater is strictly regulated by
the Environment Agency, and
tested to make sure that it meets
high-quality standards.

15. THANK YOU FOR
LISTENING!