FEATURE
49
“There is a nationwide drive
to reduce domestic water
consumption to below the
current average of 150ℓ
(Cape Town at the height of
its drought achieved 55ℓ).”
comply with the standard and in turn no guarantee that the
tanks will last.”
Filtration
To use water in the house one needs to filter it. What its end
use is determines how well it needs to be filtered.
Rainwater can be used for:
• Irrigation
• Flushing toilets and laundry only (the biggest
consumers of domestic water)
• Topping up a swimming pool
If it is drinking water that is required then the water needs
to be additionally treated, with chlorination being the most
effective and cost-effective way of killing bacteria.
Global Water Solutions’ domestic filter range consists
of premium quality housings, melt blown polypropylene
sediment filters, as well as activated carbon cartridges. On
the smaller RO units, there are also inline filters included,
along with an RO membrane.
For domestic use, GWS supplies what it calls a ‘triple JUMBO
(big blue) kit’, which filters water supplied to a house,
depending on its requirements. For drinking purposes, a
chlorine HTH (Scientific – specially designed by HTH for use
in water storage tanks) floater would be put in the water
storage tank to kill the bacteria. You would then filter the
water through the ‘triple JUMBO (big blue) kit’ for filtering for
all purposes in the house, including drinking.
In addition, GWS also offers a five-stage RO kit for inside,
which is installed beneath the kitchen sink. This purifies
the water to the purest and cleanest possible state that can
ever be achieved, says GWS Regional Manager for Southern
Africa Stuart Cooper. He adds that many people use this
system on their municipal water supply without having
the rainwater harvest component as they are not entirely
comfortable with their municipal supply and the South
African public is becoming increasingly health-conscious
about the quality of their drinking water.
The three-stage filtration system consists of a 20 micron
polypropylene filter for removing debris from the water, a
February 2020 Volume 25 I Number 12
If the objective is garden irrigation, then rainwater
is suitable and can be filtered to assist in reducing
contaminants. If the water is also planned for laundry
and toilet flushing, then rainwater and external filtration
will greatly assist in ensuring that no debris goes into
appliances where you run the risk of damage to the same.
Collecting rainwater for use in the garden is no new trend, it’s been done for decades.
carbon block and then a 5 micron filter. The system can
handle a substantial flow of 20 to 280ℓ/minute, depending
on the supply pressure.
In conclusion
Mike Muller says, “As a big picture person (more concerned
about cities, rather than individual households) I am always
keen to remind people that big dams are also a form of
rainwater harvesting. So, I sometimes question the people
who say that we must slow down stormwater runoff and let it
sink into the ground (most of the time, it then evaporates (on
the highveld at least), when we want to see it flowing into the
rivers and dams!
“At a household level, it’s a bit like trying to go off-grid
on electricity. It costs a lot and, very often, you still need
to be connected to the grid during the long dry season.
What happens then is that municipalities start charging a
'capacity charge' so you pay even if you don't use, just for
the privilege of being able to connect to the grid when you
need it.
“And when people have tried to work out whether there is
really a monetary saving, the conclusion is often that it has
not been worth it,” says Muller. PA
www.plumbingafrica.co.za