UNITED NATIONS, Mar 22 (APP): Amid growing demand for
water worldwide, a new United Nations report argues
that wastewater, discarded into the environment every day, once
treated, can help meet the needs for freshwater as well as for
raw materials for energy and agriculture.
Needless to mention, treating wastewater and removing
pollutants can also remarkably reduce the impact on the environment
as well as on health, it said.
“Improved wastewater management is as much about reducing pollution at
the source, as removing contaminants from wastewater flows, reusing reclaimed water and recovering useful by-products [as it is about increasing] social acceptance of the use of wastewater,” noted Irina
Bokova, the Director-General of the UN Educational, Scientific and Cultural Organization (UESCO) Director-General in her foreword to the World Water Development Report 2017 Wastewater: An untapped resource.
The report, launched today in Durban, South Africa, on the occasion of
World Water Day, also highlights that improved management of wastewater is essential in achieving the 2030 Agenda for Sustainable Development.
“It’s all about carefully managing and recycling the water that runs
through our homes, factories, farms and cities,” said Guy Ryder, the Director-General of the UN International Labour Organization (ILO) and the Chair of UN-Water, urging for reducing and safely reusing more wastewater.
“Everyone can do their bit to achieve the Sustainable Development Goal
target to halve the proportion of untreated wastewater and increase safe water reuse by 2030.”
Sustainable Development Goal 6 (SDG6) has specific targets on halving
the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally (target 6.3) as well as supporting countries in wastewater treatment, recycling and reuse technologies (target 6.a).
The report also revealed that low-income countries are particularly
impacted by the release of waste water into the environment without being either treated or collected, where, on average, only 8 per cent of domestic and industrial wastewater is treated, compared to 70 per cent in high-income countries.
As a result, in many regions of the world, water contaminated by
bacteria, nitrates, phosphates and solvents is discharged into rivers and lakes ending up in the oceans, with negative consequences for the environment and public health.
For instance, in Latin America, Asia and Africa, pollution from
pathogens from human and animal excreta affects almost one third of rivers, endangering the lives of millions of people.
Furthermore, growing awareness on the presence of hormones, antibiotics,
steroids and endocrine disruptors in wastewater poses a new set of complexities as their impact on the environment and health have yet to be fully understood.
These set of challenges underscore the need for urgent action on
collection, treatment and safe use of wastewater.
In addition to providing a safe alternative source for freshwater,
wastewater is also a potential source of raw materials, noted the report.
Owing to developments in treatment techniques, certain nutrients, like
phosphorus and nitrates, can now be recovered from sewage and sludge and turned into fertilizer. It is estimated that nearly 22 per cent of the global demand for phosphorus (a depleting mineral resource) can be met by treating human urine and excrement.
Similarly, organic substances contained in wastewater can be used to
produce biogas, which could power wastewater treatment facilities as well as contribute to energy needs of local communities.
In addition, use of treated wastewater is growing for agricultural
irrigation. At least 50 countries around the globe are now using treated wastewater for this purpose, accounting for an estimated 10 per cent of all irrigated land.
Lastly, the report also mentioned that treated wastewater can augment
drinking water supplies, although this is still a marginal practice. Cities such as Singapore, San Diego (United States), and Windhoek (Namibia) have been treating wastewater to supplement drinking water reserves.
A great example is use of treated wastewater, long practised by
astronauts, such as those on the International Space Station who have been reusing the same recycled water for over 16 years.