Solar steam sterilizer for treatment of human waste

Purpose

Light-absorbing nanoparticles dispersed in water and illuminated by sunlight produce steam that is used to treat human excreta.

Activities

Solar steam generation, a recent discovery from the Halas lab at Rice University, is the technological breakthrough upon which this project is based. Light-absorbing nanoparticles, when dispersed in water and illuminated by sunlight, produce steam with only secondary heating of the fluid volume: more than 80% of the solar energy absorbed by the nanoparticles is converted directly into steam, with less than 20% contributing to residual fluid heating. Due to its unparalleled high efficiency, this process produces high temperature steam rapidly, in compact, standalone geometries extremely well-suited for applications in the developing world. The nanoparticles are inexpensive, industrially produced carbon particles, and are not consumed in the steam generation process. The only input other than solar energy is water, which need not be sterilized prior to use.

Countries of activity

Location of main activity

Objectives

In Phase I we demonstrated a compact, standalone solar steam generator-driven autoclave capable of delivering high temperature steam (>130oC) for the sterilization of human waste. The prototype unit is capable of sterilizing a 14 liter volume of waste in 5 minutes (30 minute total cycling time). Both the short cycle time and the quality of the sterilized output “product” establish a new standard far above existing waste remediation methods.

Filter tags

Bill & Melinda Gates Foundation Faecal sludge treatment processes Fundamental research and engineering Global North America Product design and engineering Sub-Saharan Africa Treatment of wastewater or greywater University, education or research institution Urban (entire city)

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