Alarming statistics for sanitation accessibility around the world have prompted the development of the ‘waterless toilet’. Simeon Barut explains the ins and outs of the innovation.

Today, under half the world’s population are without access to sanitation. For this very reason, Cranfield University is developing the Nano Membrane Toilet which processes human waste without the need of energy or water – basically, the waterless toilet.

The prototype works just like a normal toilet where it accepts urine and faeces as a mixture but has added mechanisms to treat the waste onsite instead of carrying the waste to a sewage treatment plant. The ingenious creation has slowly made waves across the plumbing industry, especially with funding from the Bill and Melinda Gates Foundation. The toilet and its clever design speak for itself. Cranfield University lecturer Dr. Alison Parker says that on the surface it looks like a normal toilet, but a plethora of features enable the Nano Membrane to stand out and be the innovation the world needs.

“For the user, it’s just like a normal toilet – it accepts urine and faeces as a mixture then you just flush it and off you go. Then clever stuff happens,” says Alison.

“A rotating mechanism drops the waste into a holding tank while simultaneously blocking odour and the user’s view of the waste. The solids settle to the bottom of the tank, while the liquids fl oat on the top. The solids are then transported out of the tank by a mechanical screw into a combustor where they are burnt and transformed into ash.

“Later, the heat generated can be converted into electricity which is used to power toilet operations and any residual energy is used for charging low voltage items. The liquids pass over a weir in the holding chamber and into the membrane bundle. The unique nanostructure membrane allows clean water to be extracted from the waste which can be used in the household for whatever the user pleases.”

The first thing that runs through the minds of many people who hear this being explained is ‘what about the smell?’ Luckily this was thought about in depth by the Cranfield University creators and is solved by the toilet’s rotating mechanism which blocks odours once the toilet is flushed. In conjunction with Cranfield’s Centre for Competitive Creative Design, the rotating mechanism was designed to wipe clean the surface and trap odours by maintaining a constant barrier to the waste.

Alison notes the simplicity of the installation process and the minimal maintenance required, are two of the many advantages that the waterless toilet brings to the industry.

“As no plumbing is required, the installation process is simple – the toilet just needs to be transported to the home. Some maintenance is required every three months to clean the membranes,” says Alison.

“Other major advantages include the fact that the toilet requires no water or external power to operate which removes the entire need for plumbing, a sewage system or an electrical power supply. This will prove to be even more valuable with water scarcity rising and will also reduce water bills. Additionally, it actually produces fresh water and a small amount of power and while this may seem small to most, in the poorest areas of the world it can make a huge difference.”

Around 2.5 billion people around the world are without access to sanitation today. Ultimately, this was the inspiration behind the Nano Membrane Toilet, especially with millions of girls and women being forced outside – often risking their lives and health – in unsanitary conditions. Moreover, approximately 494 million people use shared external toilets and every day two million tonnes of human waste is disposed in water courses.

The combination of knowledge and expertise in water, membrane technology, design and energy were used to produce a household toilet that can transform human waste into useful resources.

“At the end of the day, a household toilet offers convenience, dignity and security, especially for vulnerable groups like women, the disabled and the elderly.”