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Public Lab Research note

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EDDI - Eletrodialysis Desalinator for Desalination

by mienaikoe |

Smart Electrodialysis

Electrodialysis is a method of desalination where you use electricity to move the ions of a salt into different channels of water in a parallel stack of flat channels. It has benefits over reverse osmosis in that it doesn't use plumping systems that need to be watertight under high pressure, and has a longer maintenance schedule.

By using electrodialysis, the system can also be made "smarter" by supplying a specific amount of power to get a specific salinity. This method is especially useful to farmers who often have a financial tradeoff between energy use and water quality. Oftentimes, surface water is cheaper to use, but has a high salinity. Groundwater may be of higher quality, but is expensive to pump. At times, neither option may be viable as they can both be highly saline in times of severe drought.

Electrodialysis is well fitted to using technology to increase the efficiency, but any desalination approach can be made more efficient if the application doesn't require perfectly unsalty water.

My attempt and results

I gathered a team of 6 people all in different fields for a technical challenge on the topic. We went on to win Grand Prize. Our steps are outlined here: We intend to improve/simplify the design and supply more detailed steps. We are committed to keeping the technology and our learnings open, as we anticipate desalination will be an increasingly necessary technology in years to come.

Questions and next steps

Our questions are mostly about bringing down the cost and helping people build their own desalination solutions.

Why I'm interested

We have spoken with farmers in drought areas around the world who are in a bind trying to stretch the last inch of their salty irrigation water to make their crops grow. This matters to us because climate scientists point to drought conditions becoming increasingly common, and desalination is the best solution to creating a large amount of grey water with the least amount of energy and infrastructure cost.

water-quality water desalination


@mienaikoe, This is so cool! How quickly can you process a liter of sea water? Also, you mentioned in your imgur post that you reversed the current to avoid fouling of the membranes -- how does that affect flow?

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