00:00 Domestic
taps – water running
Water
in glass
Exteriors,
Nottingham University
Guide Voice: How pure is the water we drink? Is
it good enough straight from the tap – or should we use a
water filter to get it that little bit purer?
Fighting pollution in the water supply is a major issue
throughout the world – now researchers at the University of
Nottingham in the United Kingdom have come up with a simple
solution to cleaner water that is also particularly environmentally
friendly.
00:23 SOT: Dr Gianluca
Li Puma: “This process – its name is photo
catalysis. What we actually do is we take three elements:
these are photons from light, a catalyst which is a pigment,
titanium dioxide, and water. We combine all these three together;
they interact with each other, and produce some species -
some reactive species - which then can destroy organic
pollutants in either air or water”
00:51 c.u.
Water dripping through filter
c.u.
carbon granules in filter
Water
filter and water
Guide Voice: Standard water treatment plants,
much like domestic water filters, tend to use granular activated
carbon to soak up pollution such as pesticides and oestrogens that
can find their way into the water system. These chemicals are then
burnt off – but can result in noxious chemicals entering the
atmosphere – so the pollution moves from the water to the
air.
01:13 Dr Gianluca Li Puma: “To drive
this process you can actually use solar radiation, so
in a way it’s a green process - an environmentally
friendly process - which uses sunlight to photo-activate the
catalyst. It can be used either in industrialised countries
to purify drinking water from trace organic pollutants such
as pesticides, endocrine disrupting chemicals or any small amount
of inorganics. Also, it can be used to treat waste water. For
example, the European Union will be tightening the level of
discharge of pesticides and other organic pollutants into the
water, so they need new technologies to deal with this – this
is one they can use. In developing countries this system can be
used also to supply very cheap drinking water in remote
areas.”
02:14 Water
in photo-catalytic reactor
Water
& Titanium Dioxide slurry in tank, panning to reactor
c.u.
PhD Student
2
shot – Dr Li Puma with student
Tilt
down from Dr Li Puma’s face to writing pad
c.u.
writing notes
Pull
out – students at reactor; Dr Li Puma adjusting water
flow
c.u.
hand on valve control
c.u.
Dr Li Puma at valve control
c.u.
student looking into reactor
c.u.
and pull out from nozzle to show water in reactor
Guide Voice: The “Fountain Photo
catalytic Reactor” being researched at Nottingham University
combines titanium dioxide, an inexpensive white powder, used as
pigment in paints and also in products such as toothpastes and
sunscreens, with water under UV light, in this case supplied by
ultra violet lamps.
The water and catalyst are pumped through a specially designed
nozzle, producing an umbrella shaped water fountain, creating a
canopy that maximises the absorption of UV light resulting in a
more effective removal of persistent contaminants, such as
pesticides and pharmaceutical residues. The catalyst can be
recovered and re-used after passing to a settling tank.
The system does require UV light to work; the cheapest and most
efficient source being sunlight, which could be a problem in some
countries.
03:04 SOT: Dr.
Gianluca Li Puma: “Definitely, by using sunlight
the cost will be reduced by at least 10 times. But you need to have
the sunlight available, so it will be fine for a country like Egypt
that has lots of sunlight, or Mexico, but for northern countries
then you still need to be using UV lamps. So perhaps the
applications are different here – we can use the sunlight
system to purify water in developing countries and then we use this
technology for indoor air purification in northern countries or in
the Northern Hemisphere”.
03:41 Ends
