Good job bringing this to light. People won't realise how huge the problem is and municipalities are woefully ill equipped to...
Agreed; mining can never be sustainable, but then how do you get the metals to make all the things you need in the course of...
Very good piece.
GETTING drinking water by immediate
purification of sewage, inconceivable
sopme years back, is now a reality. An
Australian company, Memtec, has
successfully used microfiltration technology to purify sewage in a small town
in the UK. The town had for the past 30
years been dumping untreated sewage
into the sea.
The company has been using this
tecnology in a range of applications,
from turning sewage into high-quality
industrial treatment water to setting up
emerging drinking water supplies for
flood-ridden communities. In Japan,
the technology is used for 'water mining' - lifting sewage locally from the
mains, and purifying it to water golf
courses and Oriental gardens (Chemical
Engineering, Vol 104, No 3)
Microfiltration involves squeezing
contaminated water through a special
membrane with tiny pores measuring
two microns (0.000002 m). This allows
only recyclable water to pass through,
leaving out all else, including the finest
particles, bacteria and viruses. The
filtration system is itself cleaned by
compressed air, which prevents it from
getting clogged with waste.
The report states that Memtec was
searching 'for a guinea-pig to try out' its
microfiltration technology on a sea beach
laden with sewage and Aberporth, a
small Welsh tourist town, was selected. It
was a radical departure from the conventional sewage treatment technology.
Memtec has completed the contract, and
Aberporth's beaches are now clean.
Memtec sells similar technology
for uses ranging from winemaking
to treatment of radioactive waste. In
the case of sewage, the extracted waste
is recycled into fertiliser. The water
obtained can be further purified
into drinking water, as is done at
Memtec plants in California, where
the authorities are concerned about
the presence of bacteria resistant to
chlorine used in standard water treatment systems. The technology has
also been used in industrial processes
such as cooling systems at power
stations in Australia. Or it may be used
to prevent pollution of water bodies
like rivers and seas, as in the case
of Aberporth, the first such use of the technology.
But the cost of the technology
remains prohibitive. Memtec's unit
operating costs are three times those of
systems that use chemicals or ultraviolet
light to clean sewage. Memtec points
out that conventional technologies are
far less efficient in removing viruses and
bacteria. While microfiltration uses
more energy than conventional methods, the capital required for setting up a
plant using the technology is less than
that for a standard plant. Moreover,
these plants are much smaller - one-
sixth the size of conventional ones.