The climate crisis is forcing us to drastically rethink our toilets

“The ultimate environmentally friendly toilet is one that doesn’t use water and doesn’t use electricity,” says Patrick Boylan, founder of Toilet Revolution, purveyor of environmentally-friendly toilets from low-flush to composting models. At the moment, environmental reasons aren’t the main reason people are opting for these. Boylan says 95 per cent of his custom is driven by necessity, and he caters to off-grid locales like national parks, campsites, or churches.

An increasingly desiccated UK could prompt a shift down the composting route. But how do these toilets work? Two main types of composting toilet straddle a great scatalogical divide: whether to mix together or divide urine and the euphemistically termed ‘solids’. “The ones that don't are what I call an internal composting toilet because all the composting happens inside the product, which is kind of what you'd expect,” says Boylan. “The second type is the separating type.” Known as urine diverting toilets, these have two different compartments and everyone – male or female – has to sit down to use them.

The climate crisis is forcing us to drastically rethink our toilets

Separating the waste is driven by a biochemical imperative. If it remains mixed, the urea in urine degrades into ammonia, which – besides stinking – kills microbes that would contribute to the decomposition of the waste. Diverting urine also means 80 per cent less waste to deal with. However, Boylan says that because the solids on their own are too dry to decompose, they have to be transported to different composting bins or waste processing facilities.

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Clearly, the composting toilet comes up trumps on the eco front, but whether people will willingly make the switch is another issue. How many would opt for handling bags of their own shit over the simplicity of the current system? “You go from flushing and forgetting and paying a small fee that's subsidised, to having to deal with it all yourself,” says Cecilia Lalander, a researcher in environmental engineering at the University of Agricultural Sciences in Uppsala, Sweden. “That's a massive change, and no one will do it. Unless you're a true enthusiast.”

Less extreme options that can be rigged up in the family home are twists on the traditional water guzzling toilets, like low-flush or dual-flush varieties. We’re most familiar with dual flush – the ones with two buttons and different volumes of water depending on whether it's pee or poo. Low-flush toilets use less water for every flush. For example, the ones that Boylan sells flush using between 300ml and 2.5 litres. Most homes in the UK now have dual flush toilets, but there are other innovations on the horizon.