The separation toilet save! has won the Design Award Switzerland 2021. This is also a milestone for Tove Larsen. She is a member of the Eawag Directorate and has been researching for almost 30 years how the nutrients in wastewater can be recovered in a useful way. In this interview on the occasion of World Toilet Day 2021, she explains how crucial our handling of wastewater is for climate change and for achieving the SDGs sustainability goals.
What do our toilets have to do with global challenges such as climate change?
Climate change – particularly fast, worldwide population growth – poses significant global challenges for us. These challenges are summarised in the Sustainable Development Goals (SDGs) and also relate to Urban Water Management. SDG 6 calls for clean drinking water and sanitary facilities for everyone as well as protecting water resources against pollution. This means that we must cut the amount of untreated wastewater worldwide in half and substantially increase the recycling and safe reprocessing of water. SDG 14 calls for reduced ocean pollution, particularly pollution from nutrients, which are present in our wastewater in massive quantities. SDG 2 is intended to end world hunger, and the recovery of nutrients from wastewater also plays a key role in this process. Even more goals depend on improving wastewater disposal and sanitary facilities.
You have been conducting research on separating wastewater streams at the source for many years. What are the advantages?
We keep the wastewater’s waste streams separate since they are then easier to clean, and first and foremeost, it is easier to recycle the resources they contain. Take urine separation, for example: If the urine is already separated in the toilet, then nutrient elimination becomes unnecessary at the wastewater treatment plant, i.e. the plants become smaller, more cost-efficient and simpler, and the nutrients can be recycled for agricultural fertilisers. This is no longer feasible at a wastewater treatment plant. It took a long time until we were able to convince a major plumbing fixture manufacturer to bring an attractive toilet to market. Our Austrian partner, Harald Gründl from design studio EOOS, recently invented the “Urine Trap”, which uses what is known as the “teapot effect” to separately collect urine in the toilet. As a result, he was able to convince Swiss plumbing fixture company Laufen to develop a new toilet that separates urine, which incidentally has now won the Design Prize Switzerland.