Researchers at the Indian Institute of Science have developed a novel waste-water filtration technique that can transform highly contaminated water into very clean water, with no water wastage. The system is membrane-less, chemical free and scalable: from a hand-held water bottle to large community based system. The system can also be used as a pre-filter for membrane based purifiers thereby improving the lifetime of the membranes.
The technology is developed by Dr. Sanjiv Sambandan of the Flexible Electronics Lab, Department of Instrumentation and Applied Physics and his team and recently won the Google Pitch Fest at Zurich, Switzerland.
The technology uses an electric field to polarise tiny impurities and cluster them into larger chunks that can then be removed by low cost meshes. If needed, these meshes can be cleaned and re-used. With just 100 mW of power needed for purifying 1 litre of very poor quality water, the system is highly efficient. This implies that the hand-held bottle purifier can be powered by a hand crank, battery or solar cell. This can be useful for people living in remote areas, people stuck in disaster hit areas, and the army. Demonstrations of cleaning bore water from Mavallipura have shown impressive results.
“The motivation was that clean water be available to people in the remotest areas and that the solution be inexpensive and almost maintenance free. I thank my department chair and division chair for their support. I also thank my project assistant, Mr. Karthik Raghunandan for his sincere efforts.” says Dr. Sanjiv Sambandan.
His team built the first system on a printed circuit board that could purify 1 microliter of water in a minute. This was far from a usable product, but a proof of concept was established. This small PC board based system won the Gandhian Young Innovator Award in 2013. Through persistent efforts and innovative methods, the team gradually improved the throughput. This was a pure technology challenge, but additionally it was essential to be able to build the system with simple materials and processes.
Dr. Sanjiv Sambandan says, “A mindset change was what we needed. We had to take our minds out of a well equipped lab to a garage setup. We thought that we should be able to make this (water purifier) with material available in the backyard”. Then they had a purification system that used no specially synthesized materials and that was easy to build. Now, the researchers are planning field tests for a community based water purification system with the required automation in place.
Until now, the project has been funded by the Division of Physical and Mathematical Sciences, IISc; Robert Bosch Center for Cyber Physical Systems, IISc; and Center for Infrastructure, Sustainable Transport and Urban Planning, IISc. Dr. Sanjiv and his team are in the process of finding sources of funding and manufacturing partners so that this idea can be made into a commercial product. More details can be found at www.openwater.in.
About the innovator: Dr. Sanjiv Sambandan is an Assistant Professor at the Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore. He leads the Flexible Electronics Lab, and Mr. Karthik Raghunandan is a Project Assistant in the lab.
Contact: +91-080-2293 3196