Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Riverbank filtration pulls pollutants from drinking water

26.08.2004


Soil beside the stream can remove harmful microbes and organic material, researchers find



Harmful contaminants often taint drinking water drawn directly from a river, but a low-cost natural filter may lie just beyond the banks. Johns Hopkins researchers have found that the soil alongside a river can remove dangerous microbes and organic material as water flows through it. The cleaner water is then pumped to the surface through wells drilled a short distance from the river.

This technique, called riverbank filtration, has been used in Europe for more than 50 years to improve the taste and smell of drinking water and to remove some hazardous pollutants such as industrial solvents. But after studying these natural filtration processes for six years at three rivers in the Midwestern United States, Johns Hopkins researchers have determined that passing river water through nearby sediment can produce other health benefits and may cut water treatment costs.


Josh Weiss, a doctoral student in the university’s Department of Geography and Environmental Engineering, presented the most recent research results on Aug. 25 in Philadelphia at the 228th national meeting of the American Chemical Society. He reported that riverbank filtration appears to significantly decrease the presence of bacteria and viruses. Water analyses also showed encouraging, though not definitive, signs that this technique can curtail Giardia and Cryptosporidium, two waterborne microorganisms that cause serious digestive ailments.

The latest results confirm the value of riverbank filtration, Weiss said. "It sounds counter-intuitive to drill wells nearby when water can be taken directly from a river," he said. "But our research indicates that riverbank filtration can naturally remove pathogens and organic material that can cause health problems, including some microbes that are able to survive conventional disinfection systems. If you think about how much it costs to build a full-scale treatment plant to make river water safe to drink, you can see how this could be very beneficial."

The research has been supported by Environmental Protection Agency grants awarded to a team led by Weiss’ doctoral advisor, Edward J. Bouwer, a professor in the Department of Geography and Environmental Engineering. The team has been studying water drawn from commercial wells located beside the Wabash, Ohio and Missouri rivers near Terre Haute, Ind.; Louisville, Ky.; and Kansas City, Mo.

In several recent papers published in peer-reviewed journals, Weiss, Bouwer and their colleagues have reported that riverbank filtration helps remove organic material left behind by decaying plants. In its natural state, this material poses no health hazards, but exposure to common water treatment chemicals such as chlorine can transform the material into cancer-causing compounds called disinfection byproducts.

"For this reason, it’s a good idea to remove as much of this organic matter as we can from the water before it’s treated with chemicals," Bouwer said. "Our research indicates that with riverbank filtration, we wind up with fewer of these dangerous disinfection byproducts in the drinking water."

Bouwer added, "Riverbank filtration doesn’t completely eliminate the need for water treatment. But it should lower the treatment costs and reduce the risks of mixing chlorine with the organic material that can become carcinogenic."

The researchers studied wells that had been constructed at varying distances – from 90 to 580 feet – from the three rivers. Over a period of days or weeks, river water moves outward toward these wells. As it travels through the sediment, the water is exposed to physical, chemical and biological processes that help remove impurities, the researchers say. Large particles may be pulled out by a straining process. Some of the chemical contaminants and microbes react with components in the sediment and remain behind, too. As a result, the water that reaches the wells is significantly cleaner than it was when it left the river.

In a campus lab, the Johns Hopkins researchers are trying to learn more about this natural filtration process by sending samples of river water through glass columns filled with sediment. They believe that soil characteristics and environmental factors such as the amount of river flow may also affect the natural filtration process.

Weiss, who is preparing his doctoral thesis on riverbank filtration, says the technique may not be appropriate in some areas, such as regions of the Western United States where rivers typically dry up in the summer. But in communities that depend on rivers for a year-round supply of drinking water, Weiss expects riverbank filtration to become more common in the coming years. "We definitely think riverbank filtration is worthwhile," he said. "We’re letting nature maintain the system, minimizing the need for external maintenance and the associated costs."

Phil Sneiderman | EurekAlert!
Further information:
http://www.jhu.edu

More articles from Ecology, The Environment and Conservation:

nachricht Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.

nachricht 100 % Organic Farming in Bhutan – a Realistic Target?
15.06.2018 | Humboldt-Universität zu Berlin

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>