Wastewater: How poo and pee can work for us all

by Richard Connor, Stefan Uhlenbrook | United Nations
Wednesday, 22 March 2017 11:12 GMT

Residents are reflected in a puddle of stagnant water as they walk in Port-au-Prince, Haiti, February 1, 2016. REUTERS/Andres Martinez Casares

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* Any views expressed in this opinion piece are those of the author and not of Thomson Reuters Foundation.

Embracing used water as a resource rather than a ‘waste’ is an essential step towards improved sanitation

Over 80 per cent of the world’s wastewater – well over 95 per cent in several developing countries – is released directly to the environment without prior treatment, with devastating impacts on human health and the environment. As the demand for water grows to meet the changing consumption patterns of increasing populations, so does the quantity of wastewater that we generate.

Wastewater has all too often been perceived as burden to be disposed of, or a nuisance to be ignored. Large centralised wastewater management and sanitation systems require a large degree of up-front capital expenditure and relatively high operation and maintenance costs, and as such are not a financially feasible option for many developing countries.

Improved wastewater management need not necessarily be an expensive endeavour. Low-cost decentralised wastewater treatment systems that service individual or small groups of properties have been gaining interest worldwide. When appropriately designed and managed, such low-cost technologies provide satisfactory results in terms of effluent quality and improved health and living conditions. It has been estimated that the investment requirements for these systems represent less than half of those of conventional treatment plants, with even lower operation and maintenance costs. But the economic arguments don’t end there.

The recovery of water, nutrients and energy from low-cost wastewater treatment schemes can provide additional revenue streams that further enhance the economic sustainability of these systems. Adequately treated wastewater can be safely used for irrigation, energy generation (e.g. cooling) and other activities. The nitrogen and phosphorus contained in domestic wastewater can be extracted to produce fertilizer, and sewage sludge is a sustainable, energy rich material that can be transformed into biogas.

Such an approach directly supports the transition to a circular economy, whereby economic development is balanced with the protection of natural resources and environmental sustainability. For example, phosphorus recovery from wastewater has become an increasingly viable alternative to scarce and depleting mineral phosphorus reserves. Recycling human urine and faeces (‘pee’ and ‘poo’) worldwide could satisfy an estimated 22% of global demand for phosphorus.

While 2.1 billion people gained access to improved sanitation facilities since 1990, 2.4 billion still do not have access to improved sanitation and nearly 1 billion people worldwide still practice open defecation. Meeting the global sanitation and wastewater management challenges may appear daunting, especially in the context of the rapid population growth occurring in cities throughout the developing world. But the 2017 edition of the United Nations World Water Development Report demonstrates that meeting the Sustainable Development Goal for water and sanitation is technically and financially feasible. Embracing used water as a resource rather than a ‘waste’ is an essential step towards making this happen.

As the report concludes, "in a world where demands for freshwater are ever growing, and where limited water resources are increasingly stressed by over-abstraction, pollution and climate change, neglecting the opportunities arising from improved wastewater management is nothing less than unthinkable."

Richard Connor is the Editor-in-Chief of the United Nations World Water Development Report at the United Nations World Water Assessment Programme (WWAP) of UNESCO.

Stefan Uhlenbrook is the Coordinator and Director of WWAP of UNESCO.