{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T15:44:06Z","timestamp":1791474246919,"version":"4.3.4"},"reference-count":26,"publisher":"IWA Publishing","issue":"7","content-domain":{"domain":["iwaponline.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2019,10,1]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Phosphate (P) recovery from urban wastewaters is an effective strategy to address environmental protection and resource conservation, aiming at an effective circular economy. Off-grid wastewater treatment systems like urine-diverting toilets (UDT) can contribute to source separation towards nutrient recovery, namely phosphorus recovery. Effectiveness of P precipitation requires a process-based knowledge regarding pH, Mg:PO4, contact time and their interactions in P recovery and crystal morphology. Several studies failed to see the process as a whole and how factors influence both morphology and P recovery for UDT hydrolysed urine. This study addressed the above-mentioned factors and their interactions, and results showed that pH and Mg:PO4 ratio are the key factors for struvite precipitation, whereas contact time is relevant for crystal growth. The recommended set of factors proposed (pH 8.5, Mg:PO4 ratio of 1.2:1 and 30 minutes contact time) not only promotes a high precipitation yield \u2013 99% of P with co-precipitation of at least 21% of ammonium (NH4+) \u2013 but also leads to larger crystals with lower water solubility (10% less crystals dissolved in water after 3 days). The obtained outcome facilitates the downstream process and leads to a more efficient slow-release fertiliser, as less P is wasted to receiving waters by leaching, minimising eutrophication processes.<\/jats:p>","DOI":"10.2166\/wst.2019.371","type":"journal-article","created":{"date-parts":[[2019,11,8]],"date-time":"2019-11-08T17:40:05Z","timestamp":1573234805000},"page":"1276-1286","update-policy":"https:\/\/doi.org\/10.2166\/iwapcrossmarkpolicypage","source":"Crossref","is-referenced-by-count":19,"title":["Recovery of phosphates as struvite from urine-diverting toilets: optimization of pH, Mg:PO4 ratio and contact time to improve precipitation yield and crystal morphology"],"prefix":"10.2166","volume":"80","author":[{"given":"Denis Manuel","family":"Rodrigues","sequence":"first","affiliation":[{"name":"Linking Landscape, Environment, Agriculture and Food \u2013 LEAF, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rita","family":"do Amaral Fragoso","sequence":"first","affiliation":[{"name":"Linking Landscape, Environment, Agriculture and Food \u2013 LEAF, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ana Paula","family":"Carvalho","sequence":"first","affiliation":[{"name":"Centro de Qu\u00edmica e Bioqu\u00edmica e Centro de Qu\u00edmica Estrutural, Faculdade de Ci\u00eancias, Universidade de Lisboa Campo Grande, 1749-016 Lisboa, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thomas","family":"Hein","sequence":"first","affiliation":[{"name":"Institute of Hydrobiology and Aquatic Ecosystem Management, Department of Water, Atmosphere and Environment, University of Natural Resources and Life Sciences, Gregor-Mendel-Stra\u00dfe, 33\/DG 1180 Vienna, Austria and WasserClusterLunz, Dr. Carl KupelwieserPromenade 5, AT-3293 Lunz am See, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ant\u00f3nio","family":"Guerreiro de Brito","sequence":"first","affiliation":[{"name":"Linking Landscape, Environment, Agriculture and Food \u2013 LEAF, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"945","published-online":{"date-parts":[[2019,11,8]]},"reference":[{"key":"2020032815003069500_WST-EM19819C1","doi-asserted-by":"crossref","unstructured":"Adnan A. 2003 Pilot-scale Study of Phosphorus Recovery Through Struvite Crystallization . Masters thesis, Department of Civil Engineering, University of British Columbia, Vancouver, Canada.","DOI":"10.1139\/s03-040"},{"key":"2020032815003069500_WST-EM19819C2","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1016\/j.cej.2016.03.148","article-title":"A design of experiments to assess phosphorous removal and crystal properties in struvite precipitation of source separated urine using different Mg sources","volume":"298","year":"2016","journal-title":"Chemical Engineering Journal"},{"key":"2020032815003069500_WST-EM19819C3","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1002\/crat.201000587","article-title":"Growth and characterization of Struvite-K crystals","volume":"46","year":"2011","journal-title":"Crystal Research and Technology"},{"key":"2020032815003069500_WST-EM19819C4","unstructured":"Dhakal S. 2008 A Laboratory Study of Struvite Precipitation for Phosphorus Removal From Concentrated Animal Feeding Operation Wastewater . Masters thesis, Department of Civil, Architectural and Environmental Engineering, University of Missouri-ROLLA, USA."},{"key":"2020032815003069500_WST-EM19819C5","doi-asserted-by":"crossref","first-page":"01018","DOI":"10.1051\/matecconf\/20165801018","article-title":"Effects of the optimised pH and molar ratio on struvite precipitation in aqueous system","volume":"58","year":"2016","journal-title":"MATEC Web of Conferences"},{"key":"2020032815003069500_WST-EM19819C6","volume-title":"Struvite Precipitation and Biological Dissolution","year":"2010"},{"key":"2020032815003069500_WST-EM19819C7","unstructured":"Gadekar S. M. 2011 Process Development for Recovery of Nutrients as Struvite and Struvite Based Products . 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