1. Biology
water recycling

2. What is recycling of
water?
•
Treatment of wastewater is
actually a remarkably simple
process that utilizes very basic
physical, biological, and
chemical principles to remove
contaminants from water. Use
of mechanical or physical
systems to treat wastewater is
generally referred to as
primary treatment, and use of
biological processes to provide
further treatment is referred to
as secondary
treatment. Advanced
secondary treatment usually
involves applying chemical
systems in addition to biological
ones, such as injecting chlorine
to disinfect the water

3. How is it done..?
• recycling graywater can
also be doncost-benefit
analysis of a free, more
labor-intensive system
versus an installed, more
expensive system is going
to be a no-brainer: a free
or cheaper system is
usually the way to go.
Many people who recycle
their graywater bootleg
it anyway (especially in
California, where the
legalities are so complex
that it makes it almost
impossible to recycle
water for less than $5,000
or $7,000).e at home

4. How is it utilized?
•
•
•
•
•
Recycled water can be used for
almost any use, as long as it is
treated to a level to make it fit
for that intended purpose (i.e.
fit-for-purpose) from a health
and environmental perspective
. However, the cost of treatment
may make reclamation
uneconomical for some uses.
Australia now has more than
600 different recycled water
schemes operating. The bulk of
these schemes involve:
Urban and municipal
environments
Households, golf courses and
recreational parks.
Industry
Washing and cooling in power
stations and mills.

5. chemistry
Hardness of
water

6. what causes hard water?
•
A c o mp o u n d c a l l e d
c a l c i um hy dr oge n
c a r bona t e i s t he
ma i n c a u s e o f h a r d
w a t e r . I t f o r ms
wh e n r a i n f a l l s o n
l i me s t o n e a n d
c ha l k r oc k s . The s e
r o c k s a r e ma d e o f
c a l c i um c a r bona t e ,
wh i c h i s i n s o l u b l e
i n wa t e r . Be c a u s e
r a i n wa t e r
c ont a i ns c a r bon
di ox i de , di s s ol v e d
f r om t he a i r , t hi s
ma k e s i t a c i d i c .
T h e r a i n wa t e r
r e a c t s wi t h t h e
r oc k s t o f or m
c a l c i um

7. How to remove hardness of water?
• Ba
p r
c h
me
wh
s o
p e
h a
wa
d o
l a
o r
h o
p u
i s
p o
e f
me
s o
s e e x c h a n g e
o c e s s ' i s a
e mi c a l
t h o d b y
i c h ,
f t e n i n g o f
r ma n e n t
r d n e s s i n
t e r c a n b e
n e o n a
r g e s c a l e
f o r
u s e h o l d
r p o s e s . I t
t h e mo s t
p u l a r a n d
f e c t i v e
a n s o f
f t e n i n g

8. Physics:
water as an energy
resource

9. Tidal energy
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Tidal energy, sometimes called tidal
power, is the power achieved by
capturing the energy contained in
moving water in tides and open
ocean currents.
There are two types of energy
systems that can be used to
extracted energy: kinetic energy, the
moving water of rivers, tides and
open ocean currents; and potential
energy from the difference in height
(or head) between high and low tides.
The first method - generating energy
from tidal currents - is becoming
more and more popular because
people believe that it does not harm
the environment as much as
barrages or dams. Many coastal
sites worldwide are being examined
for their suitability to produce tidal
(current) energy

10. Wave energy
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Wave energy is the transport of
energy by ocean surface
waves, and the capture of that
energy to do useful work – for
example, electricity
generation, water desalination, or
the pumping of water (into
reservoirs). Machinery able to
exploit wave power is generally
known as a wave energy
converter (WEC).
Wave power is distinct from the
diurnal flux of tidal power and
the steady gyre of ocean currents.
Wave-power generation is not
currently a widely employed
commercial technology, although
there have been attempts to use it
since at least 1890.[1] In 2008, the
first experimental wave farm was
opened in Portugal, at the
Aguçadoura Wave Park.[2] The
major competitor of wave power
is offshore wind power.