Nothing to W aste Liwen Xiao, A ssistant P rofessor in the School of Engineering explains how he is converting wastewater treatment plants to water resources recovery facilities and the benefits his research is going to have on our energy resources One of my research goals at Trinity is to develop advanced technologies to convert wastewater treatment plants (WWTPs) into water resource recovery facilities. Water pollutions and water shortage have become one of the major global challenges. Tens of billions of tons of wastewater are generated every day globally. The current conventional wastewater treatment technologies are not sustainable solutions for this challenge as they consume huge amount of energy and produce large amounts of greenhouse gases. In fact, wastewater contains water, organic matter and nutrients. Organic matters can be used to produce biogas or electricity. Phosphorus and nitrogen can be used as fertilizer. Therefore, with the right technologies, wastewater can be converted to resources for water, energy and nutrients. Microbial fuel cells (MFCs) are promising approaches for recovering the energy and removing pollutants from wastewater. By integrating nature-based solutions with MFCs technologies, my lab has successfully developed a small-scale WWTP that can generate electricity, recover nutrients and produce high quality effluent for water-reuse. In this system, organic matters in the wastewater are removed and converted to electricity, which is used to power a UV-LED disinfection unit at the downstream of the system to polish the treated water for reuse, while nitrogen and phosphorus in the wastewater can be used as fertilisers for plants. This system was demonstrated in the Bloom 2019 show garden (E3 Garden) in the Phoenix Park Dublin, financially supported by Trinity’s Provost’s Office. This award-winning garden was visited by the President and Taoiseach of Ireland. After the Bloom Festival, the garden was temporarily moved to Physics Square at the Trinity campus and opened by Provost in June 2019. We recently received a Commercialisation Fund grant from Enterprise Ireland to commercialise our technologies for wastewater treatment. Manufacturing large scale MFCs reactors while maintaining their performance is one of the greatest challenges for the application of MFCs in the wastewater treatment industry. The 3D electrode we invented made the enlargement of MFCs reactors feasible. In this project, the MFCs based wastewater treatment system for pollutants Removal, Resources Recovery and Disinfection (MFCs-R2D) system will be developed, tested and demonstrated for treatment of real dairy wastewater, domestic wastewater and municipal wastewater. We will apply additives manufacturing (3D printing) technologies to manufacture large scale MFCs reactors, which will increase the electrode manufacturing efficiency and improve their performance. We will then work with industry partners to develop energy-neutral wastewater treatment plants for real wastewater treatment using these large scale MFCs reactors.
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