Struvite precipitation in municipal wastewater treatment plants using a magnesium oxide by-product
[eng] Phosphorus has been classified as a critical raw material by the European Union (EU) due to its economic importance, price volatility, and supply risks. This has driven research into alternative secondary sources for phosphorus recovery, particularly in wastewater treatment plants (WWTPs), whe...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/223269 |
| Acceso en línea: | https://hdl.handle.net/2445/223269 http://hdl.handle.net/10803/695241 |
| Access Level: | acceso embargado |
| Palabra clave: | Depuració d'aigües residuals Eliminació de residus Compostos fosforosos Nutrients (Medi ambient) Purification of sewage Refuse and refuse disposal Phosphorus compounds Nutrients (Ecology) |
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| dc.title.none.fl_str_mv |
Struvite precipitation in municipal wastewater treatment plants using a magnesium oxide by-product |
| title |
Struvite precipitation in municipal wastewater treatment plants using a magnesium oxide by-product |
| spellingShingle |
Struvite precipitation in municipal wastewater treatment plants using a magnesium oxide by-product Aguilar Pozo, Verónica-Belén Depuració d'aigües residuals Eliminació de residus Compostos fosforosos Nutrients (Medi ambient) Purification of sewage Refuse and refuse disposal Phosphorus compounds Nutrients (Ecology) |
| title_short |
Struvite precipitation in municipal wastewater treatment plants using a magnesium oxide by-product |
| title_full |
Struvite precipitation in municipal wastewater treatment plants using a magnesium oxide by-product |
| title_fullStr |
Struvite precipitation in municipal wastewater treatment plants using a magnesium oxide by-product |
| title_full_unstemmed |
Struvite precipitation in municipal wastewater treatment plants using a magnesium oxide by-product |
| title_sort |
Struvite precipitation in municipal wastewater treatment plants using a magnesium oxide by-product |
| dc.creator.none.fl_str_mv |
Aguilar Pozo, Verónica-Belén |
| author |
Aguilar Pozo, Verónica-Belén |
| author_facet |
Aguilar Pozo, Verónica-Belén |
| author_role |
author |
| dc.contributor.none.fl_str_mv |
Chimenos Ribera, Josep Ma. Astals Garcia, Sergi Universitat de Barcelona. Departament de Ciència dels Materials i Química Física |
| dc.subject.none.fl_str_mv |
Depuració d'aigües residuals Eliminació de residus Compostos fosforosos Nutrients (Medi ambient) Purification of sewage Refuse and refuse disposal Phosphorus compounds Nutrients (Ecology) |
| topic |
Depuració d'aigües residuals Eliminació de residus Compostos fosforosos Nutrients (Medi ambient) Purification of sewage Refuse and refuse disposal Phosphorus compounds Nutrients (Ecology) |
| description |
[eng] Phosphorus has been classified as a critical raw material by the European Union (EU) due to its economic importance, price volatility, and supply risks. This has driven research into alternative secondary sources for phosphorus recovery, particularly in wastewater treatment plants (WWTPs), where the majority of phosphorus losses occur. In the EU, approximately 54 % of imported phosphorus is lost through wastewater. Recovering phosphorus from these streams aligns with circular economy principles and enhances resource recovery. Struvite precipitation is a promising approach for phosphorus recovery, with the potential to supply nearly 13 % of the EU’s phosphorus fertiliser demand. Additionally, phosphorus recovery can reduce its concentration in wastewater streams, leading to cost savings related to (i) chemical dosing for phosphorus removal and (ii) maintenance issues caused by uncontrolled struvite scaling in pipelines and equipment. In recent years, there has been a significant increase in full-scale phosphorus recovery facilities. North America leads in struvite production, while the EU has the highest number of operational full-scale struvite recovery units. Currently, over 80 full-scale plants worldwide recover phosphorus from industrial and municipal wastewater, employing technologies such as PHOSPAQ®, ANPHOS®, NeReSys®, Struvia™, PHOSNIX®, Ostara Pearl®, and PhosphoGREEN. These processes use MgCl2, MgO, or Mg(OH)2 as magnesium sources and they primarily increase pH by CO2 stripping or by adding NaOH. However, reagent costs pose a major limitation, as magnesium and alkaline agents account for approximately 75 % of operating expenses, particularly in streams with low phosphorus concentrations. This thesis investigates the feasibility of using an industrial by-product, low-grade magnesium oxide (LG-MgO), as a single reagent for phosphorus recovery via struvite precipitation. When added to anaerobic digestion supernatant, LG-MgO releases both magnesium and hydroxide ions, acting simultaneously as a magnesium source and an alkaline reagent. Phosphorus recovery yields ranged from 50 to 90 %, primarily influenced by the P:Mg molar ratio, the phosphorus concentration in the supernatant, and the reactivity of the LG-MgO used. The resulting precipitates consisted mainly of struvite, with a purity between 72 and 88 wt%. Significantly, the findings support struvite precipitation in streams with low phosphorus concentrations when struvite seed is added, as these conditions promote particle growth. Moreover, the use of LG-MgO reduces operating costs. An economic analysis showed that the reagent cost to produce one tonne of struvite was significantly lower when using LG-MgO (73 €) compared to MgCl2·6H2O and NaOH (940 €) at a phosphorus recovery efficiency of approximately 90 %. These findings highlight LG-MgO as a cost-effective alternative to conventional magnesium sources for struvite precipitation. Its application not only reduces operational costs but also adds value to an industrial by-product, promoting resource efficiency and advancing the circular economy. |
| publishDate |
2025 |
| dc.date.none.fl_str_mv |
2025 |
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info:eu-repo/semantics/doctoralThesis info:eu-repo/semantics/publishedVersion |
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doctoralThesis |
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publishedVersion |
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https://hdl.handle.net/2445/223269 http://hdl.handle.net/10803/695241 |
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https://hdl.handle.net/2445/223269 http://hdl.handle.net/10803/695241 |
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Inglés |
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Inglés |
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cc by-nc-nd (c) Aguilar Pozo, Verónica-Belén, 2025 http://creativecommons.org/licenses/by-nc-nd/3.0/es/ info:eu-repo/semantics/embargoedAccess |
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cc by-nc-nd (c) Aguilar Pozo, Verónica-Belén, 2025 http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
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embargoedAccess |
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application/pdf |
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Universitat de Barcelona |
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Universitat de Barcelona |
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Tesis Doctorals - Departament - Ciència dels Materials i Química Física reponame:Dipòsit Digital de la UB instname:Universidad de Barcelona |
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Universidad de Barcelona |
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Dipòsit Digital de la UB |
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Dipòsit Digital de la UB |
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1869408388733992960 |
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Struvite precipitation in municipal wastewater treatment plants using a magnesium oxide by-productAguilar Pozo, Verónica-BelénDepuració d'aigües residualsEliminació de residusCompostos fosforososNutrients (Medi ambient)Purification of sewageRefuse and refuse disposalPhosphorus compoundsNutrients (Ecology)[eng] Phosphorus has been classified as a critical raw material by the European Union (EU) due to its economic importance, price volatility, and supply risks. This has driven research into alternative secondary sources for phosphorus recovery, particularly in wastewater treatment plants (WWTPs), where the majority of phosphorus losses occur. In the EU, approximately 54 % of imported phosphorus is lost through wastewater. Recovering phosphorus from these streams aligns with circular economy principles and enhances resource recovery. Struvite precipitation is a promising approach for phosphorus recovery, with the potential to supply nearly 13 % of the EU’s phosphorus fertiliser demand. Additionally, phosphorus recovery can reduce its concentration in wastewater streams, leading to cost savings related to (i) chemical dosing for phosphorus removal and (ii) maintenance issues caused by uncontrolled struvite scaling in pipelines and equipment. In recent years, there has been a significant increase in full-scale phosphorus recovery facilities. North America leads in struvite production, while the EU has the highest number of operational full-scale struvite recovery units. Currently, over 80 full-scale plants worldwide recover phosphorus from industrial and municipal wastewater, employing technologies such as PHOSPAQ®, ANPHOS®, NeReSys®, Struvia™, PHOSNIX®, Ostara Pearl®, and PhosphoGREEN. These processes use MgCl2, MgO, or Mg(OH)2 as magnesium sources and they primarily increase pH by CO2 stripping or by adding NaOH. However, reagent costs pose a major limitation, as magnesium and alkaline agents account for approximately 75 % of operating expenses, particularly in streams with low phosphorus concentrations. This thesis investigates the feasibility of using an industrial by-product, low-grade magnesium oxide (LG-MgO), as a single reagent for phosphorus recovery via struvite precipitation. When added to anaerobic digestion supernatant, LG-MgO releases both magnesium and hydroxide ions, acting simultaneously as a magnesium source and an alkaline reagent. Phosphorus recovery yields ranged from 50 to 90 %, primarily influenced by the P:Mg molar ratio, the phosphorus concentration in the supernatant, and the reactivity of the LG-MgO used. The resulting precipitates consisted mainly of struvite, with a purity between 72 and 88 wt%. Significantly, the findings support struvite precipitation in streams with low phosphorus concentrations when struvite seed is added, as these conditions promote particle growth. Moreover, the use of LG-MgO reduces operating costs. An economic analysis showed that the reagent cost to produce one tonne of struvite was significantly lower when using LG-MgO (73 €) compared to MgCl2·6H2O and NaOH (940 €) at a phosphorus recovery efficiency of approximately 90 %. These findings highlight LG-MgO as a cost-effective alternative to conventional magnesium sources for struvite precipitation. Its application not only reduces operational costs but also adds value to an industrial by-product, promoting resource efficiency and advancing the circular economy.[cat] El fòsfor ha estat classificat com una matèria primera crítica per la Unió Europea (UE) a causa de la seva importància econòmica, la volatilitat del seu preu i els riscos de subministrament. Això ha impulsat la recerca de fonts secundàries alternatives per a la recuperació del fòsfor, especialment en les estacions depuradores d'aigües residuals (EDARs), on es produeix la major part de les pèrdues de fòsfor. A la UE, aproximadament el 54 % del fòsfor importat es perd a través de les aigües residuals. La recuperació de fòsfor d'aquests fluxos s'ajusta als principis de l'economia circular i millora la recuperació de recursos. La precipitació d'estruvita és un enfocament prometedor per a la recuperació de fòsfor, amb potencial per a proveir gairebé el 13% de la demanda de fertilitzants de fòsfor de la UE. A més, la recuperació de fòsfor pot reduir la seva concentració en els fluxos d'aigües residuals, la qual cosa suposa un estalvi de costos relacionat amb (i) la dosificació de productes químics per a l'eliminació de fòsfor i (ii) els problemes de manteniment causats per la precipitació incontrolada d'estruvita en canonades i equips. En els últims anys, s'ha produït un augment significatiu de les instal·lacions de recuperació de fòsfor a gran escala. Amèrica del Nord lidera la producció d'estruvita, mentre que la UE compta amb el major nombre d'unitats operatives de recuperació d'estruvita a escala real. En l'actualitat, més de 80 plantes a escala real a tot el món recuperen fòsfor d'aigües residuals industrials i municipals, emprant tecnologies com PHOSPAQ®, ANPHOS®, NeReSys®, Struvia™, PHOSNIX®, Ostara Pearl® i PhosphoGREEN. Aquests processos utilitzen MgCl2, MgO o Mg(OH)2 com a fonts de magnesi i augmenten el pH principalment per eliminació de CO₂ o afegint NaOH. No obstant això, els costos dels reactius suposen una limitació important, ja que el magnesi i els agents alcalins representen aproximadament el 75 % de les despeses d’operació, sobretot en corrents amb baixes concentracions de fòsfor. Aquesta tesi investiga la viabilitat d'utilitzar un subproducte industrial, l'òxid de magnesi de baixa contingut (LG-MgO), com a reactiu únic per a la recuperació de fòsfor mitjançant precipitació d'estruvita. Quan s'afegeix al sobrenedant de la digestió anaeròbia, l'LG-MgO allibera tant ions de magnesi com d'hidròxid, actuant simultàniament com a font de magnesi i com a reactiu alcalí. Els rendiments de recuperació de fòsfor van oscil·lar entre el 50 i el 90 %, influïts principalment per la relació molar P:Mg, la concentració de fòsfor en el sobrenedant i la reactivitat del LG-MgO utilitzat. Els precipitats resultants consistien principalment en estruvita, amb una puresa entre el 72 i el 88 % en pes. És important destacar que els resultats donen suport a la precipitació d'estruvita en corrents amb baixes concentracions de fòsfor quan les llavors d'estruvita s’afegeixen, ja que aquestes condicions promouen el creixement de les partícules. A més, l'ús d'LG-MgO redueix els costos operatius. Una anàlisi econòmica va mostrar que el cost del reactiu per a produir una tona d'estruvita era significativament inferior quan s'utilitzava LG-MgO (73 €) en comparació amb MgCl2·6H2O i NaOH (940 €) amb una eficiència de recuperació de fòsfor d'aproximadament el 90 %. Aquests resultats posen de manifest que l'LG-MgO és una alternativa rendible a les fonts convencionals de magnesi per a la precipitació d'estruvita. La seva aplicació no sols redueix els costos operatius, sinó que també afegeix valor a un subproducte industrial, promovent l'eficiència dels recursos i avançant en l'economia circular.Universitat de BarcelonaChimenos Ribera, Josep Ma.Astals Garcia, SergiUniversitat de Barcelona. Departament de Ciència dels Materials i Química Física2025info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/223269http://hdl.handle.net/10803/695241Tesis Doctorals - Departament - Ciència dels Materials i Química Físicareponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaIngléscc by-nc-nd (c) Aguilar Pozo, Verónica-Belén, 2025http://creativecommons.org/licenses/by-nc-nd/3.0/es/info:eu-repo/semantics/embargoedAccessoai:diposit.ub.edu:2445/2232692026-05-27T06:46:51Z |
| score |
15,81155 |