Waste that goes untreated is more than just a public health issue, claims new book.
The sanitation waste of around half the population of the world goes untreated, according to a report by the UN Environment Programme (UNEP) and the Stockholm Environment Institute. But while untreated sanitation waste carries significant public and environmental health implications, the report focuses on the missed global opportunity that this represents.
One of the lead authors of Sanitation, Wastewater Management and Sustainability: From Waste Disposal to Resource Recovery, Kim Andersson, explained: “We need to re-evaluate our view on wastewater and human excreta. Today’s approach to disposal means lost opportunities in the form of nutrients and organic matter which are being flushed away.”
The report estimates that if effective treatment were established, the presently untreated waste could meet 25% of global demand for fertiliser – which in turn could be of significant benefit if used locally to support developing rural regions. This would also represent a significant form of carbon sequestration because the return of organic matter to soil is a valuable means of removing carbon from the atmosphere.
It isn’t just fertiliser the report says we are missing out on. It also suggests that applying on-site biogas systems to presently untreated waste would generate enough energy to power 130 million homes. If that replaced diesel energy, it would cut 70m tons of CO₂ equivalent every year.
Then there is the water itself. As another UN report warns of a 40% global water shortage within ten years, this report points to municipal wastewater as a potential mitigation. If properly cleaned, the estimated 330 km3 of municipal wastewater produced globally every year would be enough to irrigate more than 40 million hectares. That is 15% of all currently irrigated cropland on earth.
The report was issued to inspire a different way of thinking about water and sanitation as the world marked World Water Day this week. Birguy Lamizana, programme management officer in charge of wastewater at UNEP, said: “I hope the book will find its way to new audiences and inspire and provide guidance on how to work towards more sustainable sanitation and wastewater management. There is great potential for resource efficiency and recovery linked to sanitation waste streams. Most circular economy initiatives do not capitalize on this component today.”