Electrochemical Reactor


  • Descriptive Overview
    Backend processing technology that capitalizes on anaerobic digestion of solids and a unique electrolysis system to convert waste into water, hydrogen, and solid fertilizer. Separate partnerships with three commercial partners (Kohler, Eram, and EcoSan) have progressed at different rates, and resulted in systems with different frontend designs, and different power and control system designs. All systems currently require power, supplied by solar panels, but may be powered by a hydrogen fuel cell in the future.
  • Use Case Details
    Demonstrated with single-stall, multi-stall, and building-level processing configurations
  • Regularly Scheduled Required Maintenance
    Sludge from the septic tank must be emptied annually.
  • Use Cases
    • Single-stall Toilet
    • Multi-stall Toilet
    • Building-level Processing
  • Frontend Description
    Various frontend configurations have been demonstrated. In all cases, urine and feces are macerated and sent together to a septic tank for processing. Some units include a superstructure and frontend, which others just provide processing for the sanitation facilities already present in a building.
  • Users per Day (Expected)
    Scalable from a single user to several hundred. Various configurations have been designed as a urinal retrofit or to support between 50 and 800 users per day.
  • Users per Day (Maximum)
  • Type of Waste Treated
    Combined Stream (solids and liquids)
  • Core Processing Technology
  • Processing Overview
    Waste flows to a septic tank with anaerobic digestion. An electrochemical system oxidizes the effluent from the septic tank at a semiconductor anode and water is reduced at the metal cathode to form H2.
  • Processing Capacity
    Scalable; previous configurations have processed 3-4 cubic meters of wastewater per day
  • Processing Parameters
    Chloride, from table salt, can be added if there is an insufficient amount in the waste. Membrane microfiltration is currently included for polishing the final effluent. Typical hydraulic retention time is more than 10 hours.
  • Gas Processing
  • Consumable Chemicals Needed
    Table salt only if there is an insufficient amount of Chloride ion in the waste
  • Power Systems Overview
    System requires an external power source. Current versions have used solar panels with Li-ion batteries for energy storage.
  • Energy Balance
    Energy requirements change with configuration, but prior versions have required between 13 and 40 Wh/L of electricity depending upon scale and presence of pretreatment options.
  • Capital Expense Estimate Notes
    Varies by configuration. One version, eToilet from Eram, has an estimated capex of $13,500.
  • Operating Expense Estimate Notes
    Varies by configuration. Current systems cost $0.02 and $0.07/user/day.
  • Current: Cost per user per day (USD)
  • Currently in Active Development
  • Commercialization Status
    Ready To Purchase
  • Commercialization Activities
    Test license in place with three commercial partners with path to commercial license (Kohler, EcoSan, and Eram).
  • Intellectual Property Status
    Patent Pending
  • Intellectual Property Details
    Patents pending in the United States, India, and China. See WO 2014/058825 A1 for further information
  • Frequency of Emptying Outputs
    Septic tank emptied periodically (probably yearly)
  • Nutrient Reuse
    At least one configuration, the Eco-san toilet, products approximately 1 ton of fertilizer per year.
Patent Number Description Link
WO2014058825 Self-contained, PV-powered domestic toilet and wastewater treatment system Link