Vortex bioreactor promises low cost sterilisation of wastewater

The system is said to be scalable, from the toilet block up to large scale treatment plants

A low cost means of sterilising waste water has been developed by researchers at Plymouth Marine Laboratory (PML), the work being published in the journal Nature Scientific Reports in late May. It could have a big impact in the developing work, according to the group. The work was undertaken in collaboration with UK-based contract research specialist Protein Technologies, and received support from the Bill and Melinda Gates Foundation. It is described as a simple technology involving some basic plumbing parts, a household drill and a model boat propeller, realising a low cost means of sterilising waste water.
“What started out as a technology to help convert microalgae into biofuels spun off ‘quite literally’ in the direction of global waste water sanitation”, commented PML Microbial Biochemist Dr Mike Allen, as the researchers recognised the broader implications of the work they were undertaking. Based on the straightforward notion of exploiting a continuous vortex contained within a pipe to bring pathogens into contact with a biocidal agent, the team now hope to launch the technology so that it can be deployed around the world to sterilise waters contaminated with faecal matter.
The system currently uses copper powder embedded in a seaweed extract as the anti-bacterial agent. “We see total destruction of bugs like E.coli after only a few minutes, and we haven’t even optimised the system yet: we’ve been focused on proving it could work first.”

Testing prototypes in the field
The PML team sent prototype vortex bioreactors as far afield as South America, North America, South Africa and India to gather data on performance. “Every locale is different with different cultures and infrastructure to deal with. We are fortunate that we have such a simple technology that is versatile enough to easily fit right in to a diverse set of situations”.
The team of researchers believe the vortex bioreactor has the potential to revolutionise the treatment of waste water in the developing world. “The beauty of the system is it’s completely scalable: we can design and build systems that work at the toilet block, village or city scale depending on the requirement. Depending on the size of the system, it can be driven by hand, bicycle or by motor. It’s a low cost, low energy, low tech, but high performance alternative to UV sterilisation” says Dr Allen.
Furthermore, the team aim to make the technology freely available for humanitarian applications. Paul Goddard, Chief Executive of PTL commented: “The vortex bioreactor is an incredibly powerful technology, one that could revolutionise high throughput liquid processing in many industries. However, in this instance, we felt we had a moral obligation to provide this technology freely to vulnerable people who really need it”.
Our priority at the moment is simply to decrease the amount of pathogens released into the environment which contaminate the waterways, by cutting the pathogens off before they get there. We have all seen pictures of children playing, cooking and cleaning themselves in filthy river waters, we hope to avoid these scenes in the future” said Dr Allen.
Published in the journal Nature Scientific Reports, the team describes the successful trials undertaken in Pune, India using real effluent samples in a working wastewater treatment plant. It is anticipated this publication will increase interest in the vortex bioreactor from charitable foundations and agencies interested in deploying new sanitation technologies in the future.