July 27, 2017 by Allie Nicodemo Jianfeng Sun and Ran Ran, both PhD'17, work on a new water filtration model inside the Nano & Micro Biomechanical Characterization and Testing Laboratory in the Forsyth Building at Northeastern University on July 25, 2017. Credit: Matthew Modoono/Northeastern University

More than 844 million people around the globe lack access to clean water. One of the challenges is that bacteria from rivers can flow into groundwater sources, polluting what may have been potable drinking water. Building new infrastructure to reroute clean water is expensive, especially for regions that already struggle with extreme poverty. Instead, communities often rely on water filtration systems.

Current methods of testing water safety can be expensive and time consuming. Researchers must first take samples at the water source and bring them back to the lab. Then they have to test the samples to determine which types of bacteria are present.

"It usually takes hours or days, and to process the data and get results takes another few hours," says Jianfeng Sun, a doctoral student in the Department of Mechanical Engineering at Northeastern University. Working with fellow doctoral student Ran Ran and undergraduate student Derek Tran, Sun is developing a new method that's faster, easier to use, and portable.

The group presented the research at the 2017 Society of Engineering Conference, hosted at Northeastern this month. Researchers and students at the conference hail from disciplines across the engineering and science spectrum. "Their work addresses a wide range of issues including energy for sustainability, sensing and control for security, and bio-nanotechnology for healthcare," said Hanchen Huang, Donald W. Smith Professor and chair of the Department of Mechanical and Industrial Engineering.

Traditionally, in order for scientists to measure what types of bacteria are present in water, they push the water sample through a column of soil or sand that's native to the riverbed where the sample came from. As the water goes through the column, some bacteria gets pushed through as well, but some gets left behind. That "sticky" bacteria adhere to the surface of sand or soil particles.

That means that some types of bacteria in rivers aren't a concern. They won't pollute groundwater because they won't ever reach it, instead getting stuck in the sand or soil of the riverbed.

However, researchers find that some bacteria will squeeze through the soil column and make it to the other side. That non-sticky stuff can be problematic. Since it's not adhering to the soil or sand, it may hitch a ride on the river current all the way into a town's source of drinking water and make people sick.

While the traditional strategy for measuring bacteria works, Sun knew he could make it more efficient. Instead of using a soil column to push water samples through, his method uses a microchannel.

If you imagine scraping a tiny ditch down the middle of a glass microscope slide, this is the microchannel where water from a sample flows. The flow is very gentle, allowing sticky bacteria to adhere to the edge of the channel. The slide is positioned over a microscope that counts individual bacteria to see which become trapped and which get flushed through.

To make this system portable, Sun knew he wanted the microscope to be able to connect with a cellphone. But there weren't any good options available. Instead of trying to retrofit his system with an existing device, he and Ran built a new microscope from scratch.

Eventually, Sun wants to develop a mobile application that will count and analyze bacteria the microscope sees. That way, researchers could bring the device into the field and test samples on the fly, cutting down on the time it takes to process data in the lab. This translates to more efficient water filtration, which has the potential to save lives all over the world.

Explore further: E. coli bacteria found in drinking water at US Open

Health officials say E. coli bacteria have been found in a drinking water station at Erin Hills golf course where the U.S. Open is underway, but there have been no reports of illness.

The lack of clean water in many areas around the world is a persistent, major public health problem. One day, tiny robots could help address this issue by zooming around contaminated water and cleaning up disease-causing ...

A University of British Columbia-developed system that uses bacteria to turn non-potable water into drinking water will be tested next week in West Vancouver prior to being installed in remote communities in Canada and beyond.

Researchers from Lund University in Sweden have discovered that our drinking water is to a large extent purified by millions of "good bacteria" found in water pipes and purification plants. So far, the knowledge about them ...

What can the forests of Scandinavia possibly offer to migrants in faraway refugee camps? Clean water may be one thing.

Research at the University of Sheffield, published in the latest issue of Water Science and Technology: Water Supply, points the way to more sophisticated and targeted methods of ensuring our drinking water remains safe to ...

If climate change is not curbed, increased precipitation could substantially overload U.S. waterways with excess nitrogen, according to a new study from Carnegie's Eva Sinha and Anna Michalak and Princeton University's Venkatramani ...

Biochar from recycled waste may both enhance crop growth and save health costs by helping clear the air of pollutants, according to Rice University researchers.

Britain said Wednesday it will outlaw the sale of new diesel and petrol cars and vans from 2040 in a bid to cut air pollution but environmental groups said the proposals did not go far enough.

A new study projects that if climate change continues unabated, heat-related deaths will rise dramatically in 10 major U.S. metropolitan areas compared to if the predicted increase in global warming is substantially curbed ...

Hydrogen at elevated temperature creates high electrical conductivity in the Earth's mantle.

The idea of geoengineering, also known as climate engineering, is very controversial. But as greenhouse gases continue to accumulate in our atmosphere, scientists are beginning to look at possible emergency measures.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Originally posted here:

Engineering a solution to dirty water - Phys.Org