...................................................................................................................................
Water Quality and Wastewater
UN-Water
Good water
quality is essential to human health, social and economic development, and the
ecosystem.
However, as
populations grow and natural environments become degraded, ensuring there are
sufficient and safe water supplies for everyone is becoming increasingly
challenging.
A major part of
the solution is to produce less pollution and improve the way we manage
wastewater.
A more circular
and therefore more sustainable economy requires us to value wastewater for its
potential, rather than discard or ignore it.
More than just
an alternative source of water, safe wastewater management could help protect
our ecosystems and give us energy, nutrients and other recoverable materials.
Challenges and opportunities
Water must be
carefully managed during every part of the water cycle: from fresh water
abstraction, pre-treatment, distribution, use, collection and post-treatment,
to the use of treated wastewater and its ultimate return to the environment,
ready to be abstracted to start the cycle again.
Due to population
growth, accelerated urbanization and economic development, the quantity of
wastewater generated and its overall pollution load are increasing globally.
The availability
of safe and sufficient water supplies is inextricably linked to how wastewater
is managed.
Increased amounts
of untreated sewage, combined with agricultural runoff and industrial
discharge, have degraded water quality and contaminated water resources around
the world.
Globally, 80% of
wastewater flows back into the ecosystem without being treated or
reused, contributing to a situation where around 1.8 billion people use a
source of drinking water contaminated with faeces, putting them at risk of
contracting cholera, dysentery, typhoid and polio.
Far from being
something to discard or ignore, wastewater will play a major role in meeting
the growing water demand in rapidly expanding cities, enhancing energy
production and industrial development, and supporting sustainable agriculture.
Wastewater and cities
Mainly in
low-income areas of cities and towns within developing countries, a large
proportion of wastewater is discharged directly into the closest surface water
drain or informal drainage channel, sometime without or with very little
treatment.
In addition to
household effluent and human waste, urban-based hospitals and industries such
as small-scale mining and motor garages, often dump highly toxic chemicals and
medical waste into the wastewater system.
Even in cities
where wastewater is collected and treated, the efficiency of treatment may vary
according to the system used.
However, water
used by a municipal authority for irrigating green spaces or cleaning streets
does not need to be treated to a potable standard.
Treating
wastewater to a water quality standard appropriate to its intended use
increases the potential for cost recovery.
The growth of
urban demand for water will require new approaches to wastewater collection and
management.
Indeed, reused
wastewater may help address other challenges including food production and
industrial development.
Wastewater and industry
Societal and
environmental pressures over recent years have led to a growing movement for
industry to reduce its wastewater and to treat it before discharge.
Wastewater is now
seen as a potential resource and its use, or recycling after suitable
treatment, can provide economic and financial benefits.
Societal and
environmental pressures over recent years have led to a growing movement for
industry to reduce its wastewater and to treat it before discharge.
Wastewater is now
seen as a potential resource and its use, or recycling after suitable
treatment, can provide economic and financial benefits.
Wastewater can be
used within the business itself or between several businesses through
‘industrial symbiosis’.
Industrial water
consumption is responsible for 22% of global water use. In 2009 in Europe and
North America, water consumption by industries was 50% as compared to 4-12% in
developing countries.
It is expected
that in rapidly industrialising countries, this proportion could increase by a
factor of five in the next 10-20 years.
Therefore, there
is a strong incentive to use wastewater in-house and locally, based on cost
savings alone.
Businesses can
directly use some wastewater, providing it is fit for purpose. For instance,
using process water for cooling or heating, or rainwater from roof collection
or concrete aprons for toilet flushing, irrigation or vehicle washing.
Wastewater in agriculture
Partly to help
maximise yields to meet demand, usage of chemical fertilizers and pesticides
has increased in recent years both in industrial and small farming, making
agriculture a potential source of environmental pollution
Pollution of
groundwater and surface water by agricultural use of untreated or inadequately
treated wastewater is a major issue in many developing countries where such
irrigation is practised.
Improved
wastewater management can improve the health of workers, especially in
agriculture, by reducing the risk of pathogen exposure.
Farmers are
increasingly looking into non-conventional water resources, mainly wastewater,
whether due to its high nutrient content or lack of conventional water
resources.
If applied
safely, wastewater is a valuable source of both water and nutrients,
contributing to water and food security and livelihood improvements.
UN-Water coordinates the
efforts of UN entities and international organizations working on water and
sanitation issues.
There is
no single UN entity dedicated exclusively to water issues. Over 30 UN
organizations carry out water and sanitation programmes, reflecting the fact
that water issues run through all of the UN’s main focus areas. UN-Water’s role
is to coordinate so that the UN family ‘delivers as one’ in response to water
related challenges.
The
overarching focus of our Members and Partners is
to support UN Member States to sustainably manage water and sanitation.
We do
this in three ways:
No comments:
Post a Comment