Truck
drivers collect water directly from the Nile river to distribute to residents
in Juba, South Sudan
|
Recycling the world's
wastewater, almost all of which goes untreated, would ease global water
shortages while protecting the environment, the United Nations said in a major
report on Wednesday.
Bhopal
residents collect drinking water from a truck, in central India
|
"Neglecting
the opportunities arising from improved wastewater management is nothing less
than unthinkable," said Irina Bokova, director-general of UNESCO, one of
several UN bodies behind the report issued on World Water Day.
For
decades, people have been using fresh water faster than Nature can replace it,
contributing in some regions to hunger, disease, conflict and migration.
Two-thirds
of humanity currently live in zones that experience water scarcity at least one
month a year.
Half
of those people are in China and India.
Last
year, the World Economic Forum's annual survey of opinion leaders identified
water crises as the top global risk over the next decade.
On
current trends, the UN Environment Programme forecasts that water demand -- for
industry, energy and an extra billion people -- will increase 50 percent by
2030.
Global
warming has already deepened droughts in many areas, and the planet will
continue to heat up over the course of the century, even under optimistic
scenarios.
"There
is an absolute necessity to increase water security in order to overcome the
challenges brought on by climate change and human influence," said
Benedito Braga, head of the World Water Council, an umbrella grouping of
governments, associations and research bodies.
Wastewater
-- runoff from agriculture, industry and expanding cities, especially in
developing nations -- is a major part of the problem.
- Problem to solution -
That
is especially true in poor countries where very little, if any, wastewater is
treated or recycled.
High-income
nations treat about 70% of the wastewater they generate, a figure that drops to
38 percent for upper middle-income countries.
In
low-income nations, only eight percent of industrial and municipal wastewater
undergoes treatment of any kind.
More
than 800,000 people die every year because of contaminated drinking water, and
not being able to properly wash their hands.
Water-related
diseases claim nearly 3.5 million lives annually in Africa, Asia and Latin
America -- more than the global death toll from AIDS and car crashes combined.
Chemicals
and nutrients from factories and farms create deadzones in rivers, lakes and
coastal waters, and seep into aquifers.
More
than 800,000 people die every year because of contaminated drinking water
|
The
200-page World Water Development Report details a four-pronged strategy for
transforming wastewater from a problem to a solution, said lead author Richard
Connor of UNESCO's World Water Assessment Programme.
Besides
reducing pollution at the source, policy initiatives must shift focus to
removing contaminants from wastewater flows, reusing water, and recovering
useful by-products, the report concludes.
"Up
to now, decision makers have mainly focused on supplying clean water rather
than managing it after it has been used," Connor told journalists.
"The
two aspects are inextricably linked."
Water
can be used over and over, he added, pointing to the fact that water from
several major rivers in the United States is recycled up to 20 times before
reaching the ocean.
- Generating energy -
The
potential for reusing liquid waste is perhaps best illustrated by astronauts on
the International Space Station who drink recycled urine and use it to wash up.
On
a larger scale, there are many nations where necessity has spawned innovative
technologies.
In
Singapore and the southern California coastal city of San Diego, residents
already drink recycled water.
In
Jordan and Israel, 90% and 50% of agricultural water, respectively, has been
recovered for reuse, according to the report.
Besides
being recycled, wastewater "can also be a rich source of nutrients,
minerals and energy -- all of which can be cost-effectively extracted,"
said Guy Ryder, chair of UN-Water, and head of the International Labour
Organization.
These
are the same elements, he added, that cause terrible damage when untreated
wastewater is released into the environment.
Harvesting
phosphorus, for example, from urine -- supplied by urine-diverting toilets --
reduces wastewater's nutrient load.
Already
in use in Australia, China and Japan, these systems can be easily scaled up.
More
than a fifth of global phosphorus demand worldwide could be met by recycled
human urine and feces, according to a recent study.
Waste
can also be converted into fuel.
A
2015 law in Japan requires sewage operators to use biosolids as a
carbon-neutral form of energy.
The city of Osaka produces 6,500 tonnes of fuel per year from 43,000 tonnes of wet sewage sludge for electricity generation.
No comments:
Post a Comment