Waste Not: New Toilet Design Makes the Most out of Waste


Waste Not: New Toilet Design Makes the Most out of Waste

Scientists in Singapore have created a new toilet system that can turn human waste into electricity and fertilizers as well as reduce water use by up to 90 percent.

Meet the cutting edge in loo design. Scientists at Nanyang Technological University (NTU) in Singapore have invented a new toilet system that will turn human waste into electricity and fertilizers. What’s more, the flushing system also saves enormous amounts of water.

No-Mix Vacuum Toilet

In their press release (titled appropriately “NTU’s new loo turns poo into power”), they call this new system the No-Mix Vacuum Toilet and say that it will reduce the amount of water needed for flushing by up to 90 percent compared to current toilet systems in Singapore.

Saving water in the bargain

They also say that, compared to an existing conventional toilet that uses about 4 to 6 litres of water per flush, a No-Mix Vacuum Toilet, installed in a public washroom, flushed 100 times a day would save about 160,000 litres in a year—enough to fill a small pool 10 x 8 x 2 metres (33 x 26 x 6.5 feet).

Recovering valuable “resources”

The design of the loo itself is not without precedent—it has two chambers that separate the liquid and solid wastes, which is something that has been used in other toilet systems being tested in Sweden and elsewhere. The No-Mix Vacuum Toilet uses vacuum suction technology like that used in airplane toilets, with only 0.2 litres of water needed to flush urine and 1 litre for solids.

The goal of this new loo design is not just to save water, but to create a complete “recovery of resources” to be used for energy and fertilizer. Conventional toilets that mix those “resources” when flushed into the sewage system make their recovery much too energy intensive to be cost-effective.

Turning poo into power

The No-Mix Vacuum Toilet diverts the separated liquid and solid wastes to processing facilities where fertilizers such as nitrogen, phosphorus, and potassium can be recovered from the urine and the solids sent to a bioreactor where it can be digested to release biogas containing methane. The methane can be used in stoves for cooking or converted to electricity to fuel power plants or fuel cells.

“Having the human waste separated at source and processed on-site would lower costs needed in recovering resources, as treating mixed waste is energy intensive and not cost-effective,” project leader Professor Wang said. “With our innovative toilet system, we can use simpler and cheaper methods of harvesting the useful chemicals and even produce fuel and energy from waste.”

Prototypes of the new toilets will be installed in two of NTU’s washrooms and they hope to introduce the new system to the world in the next three years. Their hope is that it will be useful for new housing estates, hotels, resorts, and communities that aren’t linked to existing sewage systems.

Flush out other ways to green your bathroom

In case you can’t wait for the new loos or you’re looking for other ways to turn your bathroom green, check out the tips in these articles:

  • Green Your Bathroom
  • Detox the Bathroom
  • From Tissues to Toilet Paper


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