Solar autoclave development

sun-rays-mdThe effective treatment of biohazardous clinical wastes in resource-poor regions is a huge problem.

Open burning in a pit is environmentally unsound and polluting and will not make safe all wastes. Disinfectants might provide a more practical solution but where is the supply, and the money to pay for them? Other technologies are less certain, due to impossibly high capital outlay and operating costs. Several low cost incinerators have been proposed, including at least one supported by WHO but these are themselves somewhat polluting, though if operated properly do make waste safe. However, the key is a suitable and sufficient supply of fuel and that is neither easy nor certain.

But in almost all of those regions in greatest need the sun shines brightly. That permits solar energy to be harvested as a fuel source to drive small scale sterilisation units. Though not new in concept – we have discussed them previously on the Clinical Waste Discussion Forum – several have been described over the years, a US group from Houston, Texas describer a ‘new and better’ device harnessing the sun’s rays and whizz bang  using broadband light-harvesting nanoparticles to sterilise clinical waste (Geobacillus stearothermophilus spores).

The performance data is limited to proof of concept but would be entirely acceptable in most field situations where no more sophisticated, and expensive, system was available.

Congratulations to the developers. I hope WHO are watching, and ready to support further development and field trials/sponsorship to make these available to those in need.

Houston, we have a solution!


Neumann O, Feronti C, Neumann AD et al . Compact solar autoclave based on steam generation using broadband light-harvesting nanoparticles. Proc Natl Acad Sci U S A. 2013.

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