Nanomembrane Toilet


  • Descriptive Overview
    Fully self-contained household toilet system. Frontend resembles a Western-style pedestal toilet with a novel waterless swiping flush mechanism, and all waste processing components are housed within the pedestal. In the backend, solids and liquids are settled. The solids are extracted by a specifically designed screw, then dried and combusted, while liquids are preheated and purified with a hydrophobic membrane.
  • Use Case Details
    Household: Designed as a self-contained, household unit up to 10 users per day. Supports "wipe" situations, not "wash". Multi-unit: Core processing technology could be scaled for school, or public/ community application
  • Dimensions (meters)
    L 1.25 m X W 0.75 m X H 1.0 m
  • Regularly Scheduled Required Maintenance
    Water and ash emptied daily. Membranes cleaned four times per year.
  • Use Cases
    • Single-stall Toilet
    • Multi-stall Toilet
  • Interface Type
  • Frontend Description
    User encounters a pedestal toilet with a unique waterless flush system. A rotating odor barrier and scraper mechanism manages odor and enables dry flushing. Once in the system, solids and liquids are separated by gravity sedimentation. Liquids flow over a weir to liquids processing, while the solids are extracted using a screw.
  • Flush Water Source
  • Users per Day (Expected)
    Current system designed for up to 10 users per day, but core processing technologies could be scaled up.
  • Users per Day (Maximum)
  • Type of Waste Treated
    Liquids Processing
  • Core Processing Technology
    Membrane Filtration
  • Processing Overview
    A nanomembrane pervaporation process can be used to separate water from solid and liquid contamination. A hydrophobic membrane separates clean water from the contaminated urine. The clean water is then sent to a storage tank for later use.
  • Processing Capacity
  • Processing Parameters
    The pass through and efficiency of the pervaporation process increase when the pre-treated liquid stream is heated. Membrane is off-the-shelf. Specifications: Temperature: 70 deg C Pressure: 1 bar Heat Source: Process Heat
  • Type of Waste Treated
    Solids Processing
  • Core Processing Technology
    Dry Combustion
  • Processing Overview
    Solids are dried, pelletized and combusted resulting in ash. The combustor being developed is a micro-combustor that can be fed at <1 g/min of dried fecal waste.
  • Processing Capacity
    <1 g/min
  • Power Systems Overview
    The lifting of the toilet seat powers the bowl. Excess heat from the combustor is used as the driving force for water separation.
  • Energy Balance
    There are opportunities for electrical energy generation under development from thermal and electrical gradients, to offset residual power requirements.
  • Expected Design Lifetime (Years)
  • Currently in Active Development
  • Commercialization Status
    Seeking Licensees
  • Commercialization Activities
    Commercialization partners for product development, manufacturing, and launch. Frontend and backend component prototypes developed in Cranfield, UK. Frontend tested in households in Durban, South Africa. Full system to be tested in 2019.
  • Intellectual Property Status
    Patent Granted
  • Intellectual Property Details
    Two patents published, one further patent filed.
  • Frequency of Emptying Outputs
    Water and ash to be emptied daily (by user).
  • Nutrient Reuse
    Ash and water can be used for agricultural purposes.
  • Solid Emission Characteristics
    Approximately 10 g/user/day of ash recovered.
  • Liquid Emission Characteristics
    Confirmed total pathogen removal. More than 10 L/day usable water is recovered.
  • Technology Development Milestones
  • Early Prototype
    TRL: 5 (2019)
    1. Optimized subcomponent performance 2. Frontend and backend component prototypes developed in Cranfield, UK 3. Frontend tested in households in Durban, South Africa. Full system to be tested in 2019
Patent Number Description Link
WO2017149036 Toilet and operation thereof Link