By Syed Akbar
Year 2020. A batch of space tourists, many of them from India, sips water
from special bottles after an hour of hard
exercise out in the space. There's nothing special about this bottled
water, except that it has been treated after
reclaiming from sweat, urine and breath.
The space tourists do not feel the common "yuck factor" for the simple
reason that they have already over come it,
after been used to drinking such recycled or reclaimed sewage water back
home down on the Earth. Yes, drinking
recycled sewage water will be the common norm in the next two decades with
scientists predicting acute shortage of
water because of climate changes and over exploitation of under ground water.
While the National Aeronautics and Space Administration of the United
States is busy researching on a group of 50
volunteers on the psychological, chemical and biological reactions to
consumption of water reclaimed from sewage
including toilets, the European Space Agency is preparing its scientists
on the Antarctica expedition to utilise
recycled sewage at its Concordia research station. ESA is aiming at a Mars
mission by 2030 and Concordia has
become famous for water recycling experiments. NASA volunteers often
"borrow" urine from others and drink it
after putting it through state-of-the-art treatment processes, which
eliminate all the human wastes contained in urine.
The laboratory tests of NASA and ESA apart, advanced nations like
Singapore, Australia and the USA have taken a
step forward in recycling of sewage and toilet water. They have already
been supplying, though in limited quantities,
former sewage to their citizens. Many nations in the drought-hit Africa
have taken up the project with the assistance
of the World Health Organisation and the United States. Singapore mixes
one per cent of treated sewage water with
99 per cent of natural water to reduce the psychological disgust among its
citizens. But some Australian cities have
taken up a massive advertisement campaign to "sensitise" the residents.
And back in India, we have been indirectly consuming treated sewage water
for many years without any
psychological barriers. Most of the rivers in the country are polluted
with human waste and industrial effluents and
crores of people living downstream of cities like New Delhi, Patna,
Allahabad, Nashik, Rajahmundry, Hyderabad
and Vijayawada drink water polluted by the residents. The Musi river
empties into the river Krishna near Suryapet in
Nalgonda carrying the treated sewage from Hyderabad. The Vijayawada
Municipal Corporation has set up half a
dozen such treatment plants to let out treated sewage into the three
irrigation canals that serve as drinking water
sources for lakhs of people downstream. Vijayawada discharges 66 millions
litres of sewage everyday from 31
outlets into drinking water bodies while in the case of Hyderabad it pumps
more than 300 million litres per day into
the Musi river through 18 outlets.
Even Hyderabadis drink water from Manjira and Krishna that had come out of
at least half a dozen people living
upstream of these rivers.
Though reclaimed sewage water has not yet been used for drinking in India,
several civic bodies and industrial
houses are utilising it for watering plants and lawns. A few hotels in
Hyderabad have been using the reclaimed water
for watering ornamental plants while the Municipal Corporation of
Hyderabad utilises it for its avenue plantation on
important roads and gardens.
Big industrial houses like Madras Fertilisers and Chennai Petroleum
purchase waste water from Chennai Metro,
recycle it and use the "purified" water in their cooling plants. Arvind
Mills, Rashtriya Chemicals and Fertilisers,
Kanoria Chemicals and Maruti Udyog are also known to use the recycled
water for purposes other than drinking.
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The Need
========
The question arises as to why we should go in for treated sewage and
toilet water for drinking when we have
plentiful water in reservoirs, rivers and lakes? Water management experts
argue that the quantity of water that
appears plentiful as of now may not be sufficient to meet the future needs
of the ever-growing human population.
The quantum of water is constant and this means water cannot be created
afresh. One has to recycle the existing
available water sources to meet the increased demand. Recycling sewage and
toilet water is the easiest way to
reclaim water though the cost involved is a bit high. Several civic bodies
in the US and Australia and Singapore
government supply reclaimed water at a highly subsidised rate to encourage
people to go for it. The Singapore
government, in fact, has been taking tourists to many of its recycling
plants to in a bid to create awareness on the
importance of water conservation.
"Soon water availability may be what will differentiate the haves from the
have-nots," says H Subramaniam, water
management expert and vice-president of EverythingAboutWater. "By 2025,
India will be a water-stressed country
with a water availability between 1000 and 1700 cubic metres per person
per year. Future economic and social
development is highly dependent on the availability of suitable water. The
possibility of a third world war resulting
from water-related conflict is very real. Increasingly, water is seen a
strategic resource - one to be used with caution
and managed with care," observes Subrahmaniam.
Official data and available statistics support the argument of
Subrahmaniam. The total precipitation including
snowfall over India is 4000 billion cubic metres and of this the fresh
water available for use is 1869 billion cubic
metres. This includes the replenishable ground water. Topological factors
further bring down the actual availability
of water from 1869 billion cubic metres to just 1122 billion cubic metres,
including 690 billion cubic metres of
surface water. A clear 80 per cent of this actual availability goes into
farming leaving just 20 per cent for drinking for
1.02 billion people. India's projected population by 2025 is 1.39 billion.
The country will face an acute shortage of
water in such a scenario and it will have no option but to depend on
recycled sewage water for drinking in future.
Moreover, the per capita availability of water in the country has come
down from 5277 cubic metres per person per
year in 1955 to 1970 cubic metres in 2007. By 2025, this will further go
down to anywhere between 1000 cubic
metres to 1700 cubic metres per person per year.
---------------
Purity Factor
---------------
If one sets aside the psychological barriers, the water reclaimed from
sewage and toilets is as pure as treated potable
water and in some cases purer than the bottled mineral water. Several
studies by the World Health Organisation,
scientific agencies in the US, Japan, the UK and Australia have proved
beyond doubt that treated recycled water is
perfectly fit for drinking. Scientists say there’s no scientific or health
reason that recycled waste water can’t be safely
used as part of drinking water supplies if treated properly.
Those who participated in several ‘taste and tell’ surveys reveal that
they can’t tell the difference between tap water,
bottled water and recycled water. Those in favour of recycled water argue
that it is so pure it could be used for
hospital purposes such as kidney dialysis.
Research by University of New South Wales showed that water contaminated
by pharma residues treated through
reverse osmosis system had no or nominal traces of ethinylestradiol and
paracetamol. Prior to the treatment, the
water contained 1000 ppm of these residues.
However, some experts fear that, however strict the filtration norms may
be, still some pharmaceutical residues make
way into the treated sewage and toilet water posing a health hazard to
those who drink it.
"We should ensure that the treated water is free of harmful germs," points
out Dr B Ravishankar, senior medical
gastroenterologist at Yashoda Hospital, Secunderabad.
"Psychological reasons are also important. Where usage of recycled water
is must, then we have to ensure that the
micro-organisms like E coli and others should be within the limits to make
it fit for human consumption. Otherwise,
it opens the doors to a host of infectious diseases," warns Dr Ravishankar.
The question of purity of recycled water for drinking will continue to be
debated in India as Indian toilets are said to
be dirtier than those in other countries particularly in Singapore,
Australia, the UK and the US. According to Dr
Vijay Punjabi, president of the Indian Medical Association (Maharashtra),
most Indians are unaware and ignorant
about the fact that more than 80 species of germs have been found lurking
in visibly clean toilets. "Most germs stay
stuck to the toilet bowl for over a year," he says quoting a study by
Hindustan Unilever India Limited. There's every
likelihood of these germs making way into the recycled water if the
treatment is not conducted properly.
---------------------
Treatment Process
---------------------
What exactly happens to urine, sweat, perspiration and sewage water once
it undergoes treatment? The result is water
sans impurities. Scientists are simply duplicating the Nature when they go
in for recycling of waste water for
drinking purpose. In nature, water from sweat, perspiration, open
defecation and urine goes up into the sky through
evaporation and later comes down as rain. Many of us consider rain water
as pure and do not hesitate to take a sip,
get drenched or dig into hailstones.
Water experts are now looking forward to membrane bioreactor process as
the future solution to recycling problems.
It is being projected as the future for waste water treatment. It combines
clarification, aeration and filtration in a
single stage to ensure pure water.
Other simple methods involve letting out the treated water into rivers,
streams, lakes and tanks allowing it to be
mixed with the natural water. Later this water is purified and supplied to
citizens for drinking purposes. While this is
the natural way to solve the "yuck factor", there are other proven methods
too like distillation, freezing, reverse
osmosis, electrodialysis or ion exchange. Water is pumped through fine
membranes to remove impurities and later
treated with ultra violet radiation to kill the harmful germs.
But many countries around the world are going in for what they call
indirect potable reuse. Singapore has already
adopted this method i.e. mixing a part of treated water with existing
drinking water storage bodies that later become
part of citizens' daily drinking supplies.
NASA plans to utilise its space technology on Earth to supply fresh water
to countries that are hit by perennial
drought seasons. Such recycling will be of immense use during natural
calamities like the tsunami that hit the Indian
ocean in December 2004.
Senior physicist B Raja Rao points out that sewage water could be recycled
and used and reused for about a dozen
times. "Beyond it, the water quality becomes quite bad and those sensitive
or allergic will report health problems.
The best way is to mix the treated sewage water with natural water bodies
to enhance the taste and quality," he feels.
But there are health experts like Dr GR Srinivas Rao who argue that for a
country like India which has been endowed
with natural sources of water, recycled water for drinking is not a good
idea.
"The countries, in which recycled water is used, follow stringent
purification process involving seven stages of
purification. This may not be essential in India as we have sufficient
drinking water resources. Also it may not be
viable to follow the stringent purification process, as any small loophole
somewhere can lead to a catastrophe with
diseases like gastro-enteritis, viral borne diseases like typhoid, polio,
cholera etc. spreading and assuming epidemic
proportions," says Srinivas Rao.
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