Recipe against wasting water: Swiss inventions could mean the end of the toilet

class=”sc-29f61514-0 fQbOYE”>

With 9 to 14 liters of premium drinking water wasted, we dilute our urine every time we pee. In times of water scarcity in Switzerland in the near future, this is an unacceptable waste. Or as Max Maurer, Professor of Urban Water Management Systems at ETH Zurich and Eawag puts it: “Our traditional water management is not sustainable and is reaching its limits.”

But it’s also economically and ecologically absurd that our dish and shower water go into the same “pot” or purifier as our feces: we throw out valuable chemicals such as phosphorus (urine) or nitrogen (feces). currently only classify as sewage sludge for incineration.

Under his leadership, various researchers from ETH Zurich and the Swiss Federal Institute of Water Supply, Wastewater Treatment and Water Conservation (Eawag) have long been working on the future of wastewater treatment, which should also enable the extraction of these raw materials. and reused.

The magic word here is localization: Instead of individual large wastewater treatment plants, wastewater from showers, washing, bathing and rinsing, such as gray water and feces, must be treated on site.

Liquid fertilizer is made from urine

We’ve heard about a project before: “Vuna” is a company that offers decentralized wastewater solutions, among other things – its founder Bastian Etter (40) has developed a process that turns gray water into small factories where it is produced. By hand, feces are separated by waterless separator toilets specially developed for this purpose, urine is collected and processed in an in-house facility and turned into phosphorous liquid fertilizer.

The faeces are individually composted into nutrient-rich soil. Of course, the idea takes some getting used to – but in the future we will have no choice but to make our water management more economical.

ETH now offers other projects that have already been developed for areas with less water and that could – or should – be used in Switzerland soon. Elizabeth Tilley, Professor of Global Health Engineering at ETH, for example, has developed a process that turns feces not only into fertilizer but also into biogas.

Feces are fermented in a kind of rubber balloon, producing a methane-rich gas that can be used to cook and heat food – and heat the remaining sewage sludge – to kill all pathogens and produce hygienically perfect manure.

Decentralized toilets for estates

Both concepts were originally developed for poorer countries. But ETH Professor Kai Udert of the ETH Institute of Environmental Engineering also sees great potential in this country: “The concepts we developed for poorer countries 15 years ago are now becoming more and more interesting for Switzerland as well.”

Maurer and Udert hypothesize that decentralized micro-treatment plants and small plants for the production of biogas for heating and cooking will soon be suitable for individual homes and residential areas. Depending on the creative will and determination of the political and business world, sooner or later the classic toilet flush will have its day. Absolute.

Source : Blick