Jan 8 2021
Researchers supported by a U.S. Environmental Protection Agency grant and part of a cross-campus collaboration at The University of Alabama in Huntsville (UAH) of the University of Alabama System are now working on an innovative sensor network that uses glass fibers to protect drinking water supplies.
The research is a collaboration between Dr Tingting Wu from the Department of Civil and Environmental Engineering and Dr Lingze Duan from the Department of Physics and Astronomy. Image Credit: Michael Mercier / The University of Alabama in Huntsville.
The grant is part of EPA’s P3 Awards: A National Student Design Competition Focusing on People, Prosperity and the Planet.
Under the guidance of Dr Tingting Wu, an associate professor in the Department of Civil and Environmental Engineering, and Dr Lingze Duan, a professor in the Department of Physics and Astronomy, a research team including students is making use of glass fibers to design a novel sensor network that has a centralized interrogation-detection-data processing system and distributed fiber probes for water quality monitoring in real time.
"Turbidity is caused by the existence of suspended particles, organic matter and chemicals, and is widely measured in natural resources, irrigation water, the food and beverage industry, and drinking water. As an important water quality parameter, turbidity not only indicates the efficiency of some treatment processes but also reflects water quality changes in the distribution systems."
Tingting Wu, Associate Professor, Department of Civil and Environmental Engineering, The University of Alabama in Huntsville
Elevated levels of turbidity have been associated with contamination with Cryptosporidium and Giardia and it is utilized as a surrogate measure for the threat of contamination by such pathogens. Moreover, studies have shown a powerful temporal relationship between gastrointestinal events and turbidity both during and before the serious waterborne disease outbreak in Milwaukee in 1993.
Wu stated, “All these findings emphasize the importance and necessity of turbidity monitoring in a contamination warning system.”
The turbidity quantifying systems used at present are lab-based or are heavy and costly. The huge costs and restricted timeframe for measurements can prevent their application in drinking water distribution systems. Also, higher maintenance and limited lifespan are prohibitive.
"On the other hand, fiber optical turbidity sensors possess some important advantages such as low cost, compactness, great flexibility, high stability over a wide temperature range, immunity to electromagnetic interference, water and corrosion resistance, and compatibility with multi-sensor schemes."
Tingting Wu, Associate Professor, Department of Civil and Environmental Engineering, The University of Alabama in Huntsville
According to scientists, employing glass fibers instead of the normally utilized plastic fibers also offers system benefits.
"Glass fibers have much lower loss than plastic fibers, permitting long-distance light delivery and enabling true distributed networks. They are also more compact and corrosion-resistant than plastic fibers."
Dr Lingze Duan, Professor, Department of Physics and Astronomy, The University of Alabama in Huntsville
As far as Phase 1 is concerned, the researchers have been concentrating on developing and assessing the glass fiber-based optical system under conditions relevant to drinking water. Subsequently, the architecture of the hub-spoke tracking system will be built from scratch.
“In a hub-spoke sensing network, a large number of sensor stations are linked together via a small group of central hubs, much like the nation’s airline system, where a handful of large airports connect flights from hundreds of smaller cities,” stated Dr Duan.
The benefit of the network topology is its efficiency in reducing the costs related to the interrogation-detection systems, as the service of a single central hub can be shared by several sensor stations.
A single interrogation-detection system can handle a huge number of sensors, so the researchers state that it is economically viable to develop more complex multi-function interrogation-detection systems, thus enabling multi-parametric sensor networks in the future.