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UN report: Wastewater is a hidden solution to the climate crisis 

Wastewater has been identified as a potential climate and nature solution, despite its growing threat to health and the environment, according to  a recent report from the UN Environment Programme (UNEP) and GRID-Arendal.

The report highlights the potential of wastewater as an alternative energy source for half a billion people, a means to supply over 10 times the water currently provided by global desalination capacity, and a way to offset over 10 percent of global fertilizer use.

Focus of the study

Wastewater, originating from kitchens, bathrooms, toilets, industrial and agricultural effluents, stormwater, and urban run-off, contributes to the degradation of ecosystems, including soil, freshwater sources, and oceans, which in turn exacerbates food insecurity and other social issues. 

Furthermore, the release of potent greenhouse gases such as methane and nitrous oxide from wastewater accounts for about 1.57 percent of global emissions, just below the climate harm caused by the global aviation industry.

Huge potential

The report reveals that with proper policies and management, wastewater can be transformed from a problem into a circular economy opportunity. 

This could create new jobs and revenue streams, reducing water insecurity, supporting climate change adaptation efforts, and reducing dependence on synthetic fertilizers. 

According to the experts, only 11 percent of the world’s treated wastewater is currently reused, and around half of the world’s untreated wastewater still enters rivers, lakes, and seas.

“Globally, wastewater is full of potential, yet it is currently allowed instead to contaminate the ecosystems we rely on,” said Leticia Carvalho, principal coordinator of the Marine and Freshwater Branch of UNEP.

“We must not let the opportunity simply disappear down the drain: it’s time to realize the promise of wastewater as an alternative source of clean water, energy, and important nutrients.”

Multiple opportunities 

The report calls for a reduction in the volume of wastewater produced, prevention and reduction of contamination, and management of wastewater to capture resources that can be safely reused. 

The experts also emphasize that by generating biogas, heat, and electricity, wastewater can produce about five times more energy than is required for its treatment, which could provide electricity for around half a billion people per year. 

Additionally, reusing nitrogen, phosphorous, and potassium from wastewater would help offset 13.4 percent of the global agricultural nutrient demand.

Proper wastewater management 

The report states that proper wastewater management can irrigate around 40 million hectares, nearly the size of Paraguay.

It can recover additional resources such as raw materials for producing paper, polymers, pesticides, rubber, paint, biodiesel, food preservatives and flavors, fireproofing and waterproofing fabrics, medical products, jewelry, and packaging of food, hygiene, and other products.

Improving water management and reuse is a complex challenge, but the experts have identified successful wastewater management examples from both high- and low-income countries, including the Caribbean, China, Colombia, Denmark, Egypt, Germany, India, Israel, Namibia, Senegal, Sweden, Singapore, the Solomon Islands, and Tunisia.

“We need to keep the pressure up to improve some critical underlying conditions if these actions are to succeed. For that to happen, we need more effective governance, investment, supporting innovation, strengthening data, improving capacity to implement and – critically shifting our behavior – all of us as individuals and institutions,” said Peter Harris, director of GRID-Arendal.

The Global Wastewater Initiative (GWWI) is a unique global platform that brings together various United Nations agencies, non-governmental organizations, the private sector, development banks, and other stakeholders to implement and scale up efforts to protect freshwater and marine ecosystems from wastewater pollution worldwide.


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