"Double zero" - utilising the potential of the toilet

In general, I'm attracted by what I don't know - or when what I do know appears in a new light. Most recently, the diploma project "Doppelnull" by Delia Gregori and Julian Gisler from the Industrial Design department at Zürcher Hochschule der Künste (ZHdK). The young talents have scrutinised the principle of the flush toilet. They considered human excrement as a valuable resource and explored its potential. The result? An environmentally friendly separating toilet that is geared towards a sanitary turnaround - and is a sight to behold.

Fashion instead of eco-aesthetics

"Doppelnull" is a lot prettier than most eco-toilets on the market. It impresses with its delicate lilac colour and curves as if it were made from a single mould.

The duo's research has shown that existing separating and dry toilet projects in the field of circular sanitary solutions are currently aimed at a small target group - camping fans, for example. "With an appealing and modern toilet design, we are inviting a larger target group in Switzerland to imagine the new type of toilet in their own bathroom," says Gregori. "We use a trendy fashion aesthetic in the staging of toilet use. In this way, we want to create acceptance for a taboo subject".

The design also scores points with me for its function. Because "Doppelnull" can be embedded in an alternative sanitary system and is divided into different components: In the centre is a tank for urine. Further down is a mobile container for faeces, which resembles an it-bag and ensures safe, hygienic transport.

"During our research, we bought a dry toilet and used it for a week in the attic," says Gregori. "We also looked at countless toilet models and alternative sanitation systems and spoke to professionals in the field of sewerage, sewage treatment and composting systems." Their experiences and findings from interviews with long-term users of dry separation toilets in the camping sector have been incorporated into the design of "Doppelnull" and an alternative sanitary system.

A change in the Swiss sanitary sector

"The linear Swiss sanitary system is an obsolete model," explains Gisler. "It interrupts the material cycle intended by
the material cycle intended by nature: The nutrients removed from the soil do not find their way back in a natural way." The visionary toilet litter, on the other hand, separates urine from faeces in order to process the various substances into humus soil and fertiliser for agriculture in a more targeted manner and with less energy input. "In this way, for example, the Swiss population could almost independently cover its phosphorus and nitrogen requirements in agriculture."

The vision of "Doppelnull" is intended to stimulate discourse and be a proposal that can be followed up on. The duo is keeping Switzerland as a business location thanks to the expertise of institutions such as EAWAG - a water research institute at ETH University - and Swiss sanitary companies such as Laufen and Geberit are well placed. "As a next step, we would like to organise workshops to test the impact of our idea and document the opinions in order to further develop our sanitary vision in a participatory way."

From 3 September to 19 November, you can see the alternative design for the flush toilet for yourself. The graduation project will then be exhibited at Zurich's city nursery.