Date post: | 22-Dec-2015 |
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Water Facts:70% of the Earth is
covered by water but only 2% is drinkable, fresh water
One litre of wastewater pollutes about eight litres of freshwater
It’s estimated that there is 12,000 km3 of freshwater worldwide
How is polluted water cleaned?Not easy to reverse the effects of water pollution
It can be very expensive tooThere are 2 common ways to fix pollution…what would they be??Remove the pollution sourceRemove the contaminants
Removing the source:Depends on the source and the type of pollutionCould be from one of 3 source types:
Point sourceThe exact place where pollution occurs can be
identifiednon-point source
The exact place where pollution occurs cannot be identified but the region can be identified
Transboundary sourceThis type of pollution occurs across
governmental boundariesWhich types of pollution can you identify from the
picture on the previous slide?
Why not remove the source all of the time?
If removing the source of the pollution gets rid of it… why not do it all of the time??Finding the actual polluter
CostOthers?
Removing the contaminants:This is the second way to clean up
water pollution - Five techniques are used
Can be used individually or in combination
Most involve pumping the water out, treating the water, and then pumping it back to the source
Air Stripping:Uses air to remove contaminants that
evaporate easilyPolluted water is pumped back into a
tank and then sprayed over packing material
Water slowly drips through the packing material and a fan blows over the water to help it evaporate
Chemicals collected at the top of the tank are treated to prevent further pollution
Activated Carbon Filtration:Polluted water is sent
through columns of activated carbon
Chemicals stick to the surface & pores of the carbon granules and clean water flows through
Filters are cleaned or replaced when they are full
Bioremediation:Uses naturally occurring microorganisms
to digest contaminantsContaminants are converted to
water and other gases such ascarbon dioxide
Often used in wastewater treatment plants in cities and can be used for drinking water too
Phytoremediation:Plants & trees are used to
remove pollutantsThe roots of the plant
take up the contaminants at the same time as water and nutrients
Contaminants are stored in the roots and leaves