The Nano Membrane Toilet

Designed for single-household use. The toilet aims to treat human waste in the home without external energy or water. The flush uses a unique rotating mechanism to transport the mixture into the toilet without demanding water whilst blocking odour and the user’s view of waste.

Overview

cross-section toilet Nano Membrane Toilet prototype Nano Membrane Toilet

 

Cranfield University is developing the Nano Membrane Toilet, designed for single-household use (equivalent to ten people). The toilet is designed to accept urine and faeces as a mixture. The toilet flush uses a unique rotating mechanism to transport the mixture into the toilet without demanding water whilst simultaneously blocking odour and the user’s view of the waste.

Solids separation (faeces) is principally accomplished through sedimentation. Loosely bound water (mostly from urine) is separated using low glass transition temperature hollow-fibre membranes. The unique nanostructured membrane wall facilitates water transport in the vapour state rather than as a liquid state which yields high rejection of pathogens and some odorous volatile compounds. A novel nano-coated bead enables water vapour recovery through encouraging the formation of water droplets at the nanobead surface. Once the droplets form a critical size, the water drains into a collection vessel for reuse at the household level in washing or irrigation applications.

Following release of unbound water, the residual solids (around 20-25% solids) are transported by mechanical screw which drops them into into a coating chamber lined with a replaceable bag. Once inside the coating chamber, the solid matrix is periodically coated with a biodegradable nano-polymer. The nanopolymer coating serves to block odour and acts as a barrier to pathogen transport. The toilet will be powered using a modular hand crank or bicycle power generator supplied for household use that can also power other low voltage items (eg mobile phones).

The replaceable bag comprising the coated solids is periodically collected for transport to a locally sited small scale gasifier sized to accommodate around 40 toilets. Both toilet maintenance and solids collection will be undertaken with a trained operative responsible for the franchised area.






Cranfield's impact

Exhibited at 'Reinvent the Toilet' Fair, Delhi, March 2014.  Seeking further funding to develop into pre-production prototype.

Cranfield University’s Nano Membrane Toilet has been announced as a finalist for the fourth Cleantech Innovate showcase by ecoConnect CIC, the UK’s green industry business network.

Main findings

Prototypes of the Nano Membrane Toilet

Nano Membrane Toilet

Related academics

Associated Publications

Visit project website

Further information