2017/03/22 Dresden, Germany
Over 2 billion people – or almost a third of the world’s population – still lack access to improved sanitation (UNESCO 2017). Yet over 80% of the wastewater generated by society flows back into the ecosystem without being treated or reused (UN-Water 2014). So why waste water?
In a world where vital resources are increasingly finite, wastewater can be a great source of energy for households, irrigation, and fertilisation. On World Water Day, we take action on water issues. Celebrated on 22 March annually, this year’s focus is on reducing and reusing wastewater. In conjunction with this day, UNU-FLORES researchers have taken the lead to explore this topic in a series of articles on The Conversation.
Sustainable Development Goal (SDG) Target 6.3 requires us by 2030 to “improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally.”
The benefits of water reuse are enormous. Wastewater is so much more than dirty water – in agriculture, it can increase yields, cut the need for fertilisers, and improve soil quality; and if collected and treated properly, it could provide drinking water. In addition, the by-product of sewage treatment – sludge – can be used to produce energy. Some treatment plants even use it for renewable energy purposes.
Progress towards Target 6.3 of the Sustainable Development Goals will also help achieve the SDGs on health and wellbeing (SDG 3), safe water and sanitation (SDG 6), affordable and clean energy (SDG 7), sustainable cities and communities (SDG 11), life below water (SDG 14), and life on land (SDG 15), among others.
Just as the benefits of wastewater use is huge, so are the opportunities for it.
Cycles of water, nutrients, and carbon are interconnected – by exploiting these linkages, we can look towards systems that perform multiple functions optimised to provide services for human communities, while improving ecosystem health.
Such a Nexus Approach towards resources management calls for sustainable wastewater treatment systems. A constructed wetland is one such system: on the surface it looks scenic and provides refuge for wildlife; beneath the surface it treats wastewater and produces energy.
The inevitable use of wastewater also trickles down to the issue of food production. More than 20 million hectares of land are irrigated with wastewater today; but much of it is not based on any scientific criteria ensuring its safe use. Various forms of hazardous materials including antibiotic-resistant bacteria can be found in wastewater – the benefits of water reuse may come at the cost of public health.
UNU-FLORES’s Safe Use of Wastewater in Agriculture (SUWA) initiative aims to raise the awareness and push to implement minimum standards for water reuse for agricultural purposes.
While it is important to recognise not just the benefits but also the risks of using wastewater, there is no denying that wastewater is the future. So instead of viewing it as a costly problem, it is about time we unleash the untapped resource and see its true value. The United Nations World Water Development Report 2017 published by UNESCO today reiterates the critical need to improve the management of wastewater for our common future.
Hettiarachchi, Hiroshan and Reza Ardakanian, eds. 2016. Safe Use of Wastewater in Agriculture: Good Practice Examples. Dresden: UNU-FLORES.
WWAP (United Nations World Water Assessment Programme). 2017. The United Nations World Water Development Report 2017. Wastewater: The Untapped Resource. Paris, UNESCO.