Recycling resources present in wastewater fractions such as human urine can contribute to achieving a sustainable future and circular economy in the sanitation space. Such recycling could reduce human impacts on several planetary boundaries, including the natural cycles of nitrogen and phosphorus, while also benefitting existing centralised wastewater treatment plants. My work supports such a transition in the water and sanitation space.
My current research focuses on developing technologies for treating human urine to produce a) concentrated fertilisers (e.g., granurine, urine-based fertiliser pellets containing >15% nitrogen); (b) high-value chemicals (e.g., vivianite); and (c) clean water. I am also developing techniques to remove heavy metals, pathogens and micropollutants like pharmaceutical drugs from urine or urine-based products.
I am a contributing author to the flagship report of United Nations Environment Program and Global Wastewater Initiative, titled ‘Wastewater – Turning Problem to Solution’, and a member of the management committee for the Specialist Group on Resource-Oriented Sanitation of the International Water Association.
My research involves a combination of natural science (inorganic and organic chemistry, biochemistry, environmental sciences, and material sciences) and engineering (chemical, environmental, civil and process engineering). I also work with systems engineering to analyse and identify strategies for introducing new sanitation technologies and behaviours in society. The emphasis is on both fundamental and applied science research, including prototyping, field-testing and implementation of new technologies in real world settings.
Research Projects
Ph.D. Technology, Swedish University of Agricultural Sciences
Erasmus Mundus M.Sc. Environmental Sciences, Policy, & Management (MESPOM): University of Manchester, Lund University, Central European University, University of Aegean.
B. Tech. Chemical Process Engineering at VIT University, India. Indus–Magic scholar at National Chemical Laboratory, CSIR India. Summer Research Fellow at Institute of Chemical Technology, India.
Simha, P.*, Vasiljev, A., Randall, D. G., & Vinnerås, B. (2023). Factors influencing the recovery of organic nitrogen from fresh human urine dosed with organic/inorganic acids and concentrated by evaporation in ambient conditions. Science of The Total Environment, 163053.
Demissie, N., Simha, P., Lai, F.Y., Ahrens, L., Mussabek, D., Desta, A. and Vinnerås, B. (2023). Degradation of 75 organic micropollutants in fresh human urine and water by UV advanced oxidation process. Water Research, 120221.
Simbeye, C., Courtney, C., Simha, P.*, Fischer, N., & Randall, D. G. (2023). Human urine: A novel source of phosphorus for vivianite production. Science of The Total Environment, 164517.
Perez-Mercado, L. F., Perez-Mercado, C. A., Vinnerås, B., & Simha, P.* (2022). Nutrient stocks, flows and balances for the Bolivian agri-food system: Can recycling human excreta close the nutrient circularity gap? Frontiers in Environmental Science, 10, 956325.
Aliahmad, A., Harder, R., Simha, P., Vinnerås, B., & McConville, J. (2022). Knowledge evolution within human urine recycling technological innovation system (TIS): Focus on technologies for recovering plant-essential nutrients. Journal of Cleaner Production, 134786.
Simha, P.*, Deb, C. K., Randall, D. G., & Vinnerås, B. (2022). Thermodynamics and Kinetics of pH-dependent Dissolution of Sparingly Soluble Alkaline Earth Hydroxides in Source-Separated Human Urine Collected in Decentralised Sanitation Systems. Frontiers in Environmental Science, 10, 889119.
Zhou, X., Simha, P.*, Perez-Mercado, L. F., Barton, M. A., Lyu, Y., Guo, S., ... & Li, Z. (2022). China should focus beyond access to toilets to tap into the full potential of its Rural Toilet Revolution. Resources, Conservation and Recycling, 178, 106100.
Vasiljev, A., Simha, P.*, Demisse, N., Karlsson, C., Randall, D. G., & Vinnerås, B. (2021). Drying fresh human urine in magnesium-doped alkaline substrates: Capture of free ammonia, inhibition of enzymatic urea hydrolysis & minimisation of chemical urea hydrolysis. Chemical Engineering Journal, 428, 131026.
Simha, P.*, Barton, M.A., Perez-Mercado, L.F., et al. (2021). Willingness among food consumers to recycle human urine as crop fertiliser: Evidence from a multinational survey. Science of The Total Environment, 765, 144438.
Simha, P.*, Lalander, C., Nordin, A., & Vinnerås, B., 2020. Alkaline dehydration of source-separated fresh human urine: Preliminary insights into using different dehydration temperature and media. Science of The Total Environment, 733, 139313.
Simha, P.*, Karlsson, C., Viskari, E-L., Malila, R., and Vinnerås, B. (2020) Field testing a pilot-scale system for alkaline dehydration of source-separated human urine: a case study in Finland. Frontiers in Environmental Science, 8, 570637.
Simha, P.*, Senecal, J., Gustavsson, D. J., & Vinnerås, B. (2020). Resource recovery from wastewater: a new approach with alkaline dehydration of urine at source. In Current Developments in Biotechnology and Bioengineering (pp. 205-221). Elsevier.
Simha, P.*, Lalander, C., Ramanathan, A., Vijayalakshmi, C., McConville, J. R., Vinnerås, B., Ganesapillai, M., 2018. What do consumers think about recycling human urine as fertiliser? Perceptions and attitudes of a university community in South India. Water Research 143, 527-538.
Simha, P.*, Senecal, J., Nordin, A., Lalander, C., Vinnerås, B., 2018. Alkaline dehydration of anion–exchanged human urine: Volume reduction, nutrient recovery and process optimisation. Water Research 142, 325-336.
Senecal, J., Nordin, A., Simha, P., Vinnerås, B., 2018. Hygiene aspect of treating human urine by alkaline dehydration. Water Research, 144, 474-481.
Simha, P., Lalander, C., Vinnerås, B., Ganesapillai, M., 2017. Farmer attitudes and perceptions to the re–use of fertiliser products from resource–oriented sanitation systems–The case of Vellore, South India. Science of The Total Environment, 581-582, 885–896.
United Nations Environment Programme (2023). Wastewater – Turning Problem to Solution. A UNEP Rapid Response Assessment. Nairobi, Kenya. [features three case studies on urine source-separation and recycling from SLU/S360]
Simha, P., Vinnerås, B. (2022). The disruptive opportunity for mainstreaming urine recycling. IWA Source Magazine.
Simha, P., Buckley, C., Senecal, J. (2020) We developed a simple process to recycle urine. Here’s how it’s done. The Conversation Africa.
Simha, P., Vinnerås, B., Senecal J. (2020) We found a way to turn urine into solid fertiliser – it could make farming more sustainable. The Conversation UK.
Simha, P., Alkaline Urine Dehydration: How to dry source-separated human urine and recover nutrients? Doctoral Thesis, Sveriges lantbruksuniversitet, Acta Universitatis Agriculturae Sueciae, 1652-6880.
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