Water & Wastewater Treatment Magazine
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32 | FEBRUARY 2018 | WWT | www.wwtonline.co.uk mentally friendly since the paper sensor is made of biodegradable components. The device is also easy to use and transport, weighing less than 1g. The University of Bath researchers are now investigating how to link up the sensor with an electronic device such as a mobile phone, via a wireless transmitter, for a quick and user-friendly way of iden- tifying if a water supply is safe to use. Lead author and Senior Lecturer in the University of Bath's Department of Chemical Engineering, WIRC @ Bath & CSCT, Dr Mirella Di Lorenzo, said: "This work could lead to a revolutionary way of testing water at the point of use, which is not only green, easy to operate and rapid, but also affordable to all. "This type of research will have a significant positive impact, especially benefitting those areas where access to even basic analytic tools is prohibitive. This device is a small step in helping the world realise the United Nations call to ensure access to safe drinking water and sanitation as a human right." Co-author and Reader in the Univer- sity of Bath's Department of Chemistry and CSCT, Dr Janet Scott added: "This is a great example of how scientists and engineers working closely together can develop useful technologies with the po- tential to impact positively on the lives of citizens globally – we were able to design the materials that facilitated the produc- tion of these devices and the engineering partners designed the devices." In addition to researchers in the University of Bath's Water Innovation & Research Centre and Centre for Sustain- able Chemical Technologies, the multi- disciplinary project involved researchers from the University of Bath's Department The knowledge: water quality HOW IT WORKS • Microbial fuel cells (MFCs) are devices which use bacteria to convert the chemical energy contained in organic matter into electricity, via the metabolic processes of microorganisms. The current generated is directly linked to the activity of the bacteria, making MFCs a useful indicator of water quality and in particular the level of organics present. • To be of maximum use in the context of the developing world, water quality sensors must be easy and cheap to produce, with minimal components and made from readily available materials. The newly developed paper sensor meets these criteria, as it is a single component which can be produced by screen printing at an estimated cost of 43p. It is an example of paper electronics, in which paper is a functional part of the electronic components of a device. • The paper is printed with special conductive ink made of cellulose dissolved in an organic electrolyte solution. Two printed sheets are folded back-to-back and electrodes attached to make an electrical connection. When the paper is then dipped in the water to be tested, biofilms form and an electrical current begins to flow. • The research team believe that linking up the sensor to a device such as a mobile phone could provide a quick and user-friendly way of identifying if a water supply is safe to use. of Mechanical Engineering and a partner- ship with the Brazilian Nanotechnology National Laboratory in the State of Sao Paulo, Brazil. This research received funding from the Global Challenges Research Fund (GCRF) through the Engineering and Physical Sciences Research Council (EPSRC). The full academic paper 'A screen-printed microbial fuel cell biosensor for detection of toxic compounds in water' is published in the Biosensors and Bioelectronics Journal, vol.102, (Authors: Chouler, Cruz-Izquierdo, Rengaraj, Scott, Di Lorenzo) and is freely available online at www.sciencedirect.com A diagram of how the paper sensor works