Assessment of K-Struvite Precipitation as a Means of Nutrient Recovery from Source Separated Human Urine

Işık Kabdaşlı; Sezen Kuşçuoğlu; Olcay Tünay; Alessio Siciliano

doi:10.3390/su14031082

Assessment of K-Struvite Precipitation as a Means of Nutrient Recovery from Source Separated Human Urine

Işık Kabdaşlı^*, Sezen Kuşçuoğlu, Olcay Tünay, Alessio Siciliano

^*Corresponding author for this work

Department of Environmental Engineering

Research output: Contribution to journal › Article › peer-review

20 Citations (Scopus)

Abstract

The impact of nutrients on the environment, particularly on water bodies, has led to extensive studies for nutrient control. Within this context, studies have been focused on source separation of human urine from domestic wastewater to recover nutrients. Potassium is one of the most important components of human urine. However, data on potassium removal or recovery are quite limited except for some indirect information through use of zeolites for mostly ammonia removal. Potassium struvite or K-struvite (MgKPO₄·6H₂ O) is a sparingly soluble salt belonging to the struvite family that has the potential of being used as a means of potassium and phosphate recovery from segregated human urine. This study aimed to assess the potential of K-struvite precipitation for control and recovery of nutrients. Within this context, K-struvite precipitation experiments were performed on both synthetically prepared samples and synthetic human urine solution to determine effect of operation parameters i.e., pH, stoichiometry, and temperature on potassium recovery performance. Results indicated that process performance as well as type of solid phases co-precipitated with K-struvite were closely related to initial potassium concentration, pH, and reaction stoichiometry. At pH 10, the potassium recovery efficiency was maximized up to 87% by application of 100% excess dose of Mg and P for both synthetic samples and synthetic human urine solution. On the other hand, application of excess dose of K did not provide any improvement in K recovery efficiency. The effect of temperature on solubility of K-struvite was insignificant at the temperature range of 24–90^◦ C. Solid phase analyses confirmed that K-struvite was co-precipitated with either Mg₃ (PO₄)₂, MgNaPO₄·7H₂ O, or MgHPO₄·7H₂ O depending on pH and stoichiometry instead of a pure compound.

Original language	English
Article number	1082
Journal	Sustainability (Switzerland)
Volume	14
Issue number	3
DOIs	https://doi.org/10.3390/su14031082
Publication status	Published - 1 Feb 2022

Bibliographical note

Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Funding

etfifoicnie wncays oafcc8o5m%pcaonrrieedspboyndoitnhgert osoalimdsa,xsimpeucmificoanlelyfoMr gsy3(nPtOhe4)t2i,c MsagmNpalPesOa4·t7pHH2O1,0 a.0n2d. AlmostMgHPOequal4·7H2KO. recovery efficiency (87%) was obtained for synthetic human urine at pH 10.04 and 100% excess dose of Mg and P. •SuppInleamlletnhtearsye Mpraetceirpiiatlast: iTohnee fxoplleorwiminegn atrsep aevrafoilramblee donulsininegats ywnwthwe.tmicdaplliy.cpomre/pxaxrxe/sd1,s aTmabplel eSs1,: RecipPea onfd syMntghewtiecr heuamlmano sutricnoem upseledteinly thpirsesctiupdiyta [t3e4d].. Table S2: Effect of duration on K-struvite • As evidenced by XRD results, K-struvite did not precipitate alone, but its precipita-tion was accompanied by other solids, specifically Mg3(PO4)2, MgNaPO4·7H2O, and on K-struviteMgHPO4re·7H2covery (K/MgO. /P: 10/10/10 mM). Figure S1: XRD analysis (K/Mg/P: 250/250/250 mM, pH 10.01). Figure S2: XRD analysis (K/Mg/P: 125/250/250 mM, pH 10.03). Figure S3: XRD analysis (K/Mg/P: 100/100/100 mM, pH 10.05). Supplementary Materials: The following are available online at https://www.mdpi.com/article/10.3 Author Contributions: Conceptualization, I.K. and O.T.; methodology, I.K. and O.T.; supervision, 390/su14031082/s1, Table S1: Recipe of synthetic human urine used in this study [34]. Table S2: Effect I.K.; experimental study—data production, S.K.; writing—review and editing, I.K., O.T. and A.S., of duration on K-struvite precipitation performance. Table S3: Effect of temperature on K-struvite pre-All authors have read and agreed to the published version of the manuscript. cipitation performance. Table S4: Effect of pH on K-struvite precipitation (K/Mg/P: 250/250/250 mM), TFaubnledSin5:g:ETffheicstroefsepaHrcohn wKa-ssfturunvdieted rbeycoİvstearnyb(uKl /TMecgh/nPic:a1l0U/n10iv/e1r0simtyMun).dFeirg uPrreojSe1c:t XNRuDmbanera lByAsiPs- (K32/4M36g. /P: 250/250/250 mM, pH 10.01). Figure S2: XRD analysis (K/Mg/P: 125/250/250 mM, pH 10.03). Figure S3: XRD analysis (K/Mg/P: 100/100/100 mM, pH 10.05). Institutional Review Board Statement: Not applicable. Author Contributions: Conceptualization, I.K. and O.T.; methodology, I.K. and O.T.; supervision, Informed Consent Statement: Not applicable. I.K.; experimental study—data production, S.K.; writing—review and editing, I.K., O.T. and A.S. All aDutahtoar As vhaaivleabreilaidtya Sntdataegmreeendt:tDoathtae rpeupbolritsehde dinv theriss isotnudoyf tahree mdualnyuasvcraiiplat.ble from the corresponding author on reasonable request. ˙ Funding: This research was funded by Istanbul Technical University under Project Number BAP-32436. Conflicts of Interest: The authors declare no conflict of interest. Institutional Review Board Statement: Not applicable. Acknowledgments: The authors are thankful to Mehmet Kobya for SEM and XRD analyses.

Funders	Funder number
Istanbul Teknik Üniversitesi	BAP-32436

Keywords

Human urine
K-struvite precipitation
Nutrient recovery
Operation parameters
Solid phases

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.3390/su14031082

Cite this

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title = "Assessment of K-Struvite Precipitation as a Means of Nutrient Recovery from Source Separated Human Urine",

abstract = "The impact of nutrients on the environment, particularly on water bodies, has led to extensive studies for nutrient control. Within this context, studies have been focused on source separation of human urine from domestic wastewater to recover nutrients. Potassium is one of the most important components of human urine. However, data on potassium removal or recovery are quite limited except for some indirect information through use of zeolites for mostly ammonia removal. Potassium struvite or K-struvite (MgKPO4·6H2 O) is a sparingly soluble salt belonging to the struvite family that has the potential of being used as a means of potassium and phosphate recovery from segregated human urine. This study aimed to assess the potential of K-struvite precipitation for control and recovery of nutrients. Within this context, K-struvite precipitation experiments were performed on both synthetically prepared samples and synthetic human urine solution to determine effect of operation parameters i.e., pH, stoichiometry, and temperature on potassium recovery performance. Results indicated that process performance as well as type of solid phases co-precipitated with K-struvite were closely related to initial potassium concentration, pH, and reaction stoichiometry. At pH 10, the potassium recovery efficiency was maximized up to 87% by application of 100% excess dose of Mg and P for both synthetic samples and synthetic human urine solution. On the other hand, application of excess dose of K did not provide any improvement in K recovery efficiency. The effect of temperature on solubility of K-struvite was insignificant at the temperature range of 24–90◦ C. Solid phase analyses confirmed that K-struvite was co-precipitated with either Mg3 (PO4)2, MgNaPO4·7H2 O, or MgHPO4·7H2 O depending on pH and stoichiometry instead of a pure compound.",

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author = "I{\c s}ık Kabda{\c s}lı and Sezen Ku{\c s}{\c c}uoğlu and Olcay T{\"u}nay and Alessio Siciliano",

note = "Publisher Copyright: {\textcopyright} 2022 by the authors. Licensee MDPI, Basel, Switzerland.",

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T1 - Assessment of K-Struvite Precipitation as a Means of Nutrient Recovery from Source Separated Human Urine

AU - Kabdaşlı, Işık

AU - Kuşçuoğlu, Sezen

AU - Tünay, Olcay

AU - Siciliano, Alessio

PY - 2022/2/1

Y1 - 2022/2/1

N2 - The impact of nutrients on the environment, particularly on water bodies, has led to extensive studies for nutrient control. Within this context, studies have been focused on source separation of human urine from domestic wastewater to recover nutrients. Potassium is one of the most important components of human urine. However, data on potassium removal or recovery are quite limited except for some indirect information through use of zeolites for mostly ammonia removal. Potassium struvite or K-struvite (MgKPO4·6H2 O) is a sparingly soluble salt belonging to the struvite family that has the potential of being used as a means of potassium and phosphate recovery from segregated human urine. This study aimed to assess the potential of K-struvite precipitation for control and recovery of nutrients. Within this context, K-struvite precipitation experiments were performed on both synthetically prepared samples and synthetic human urine solution to determine effect of operation parameters i.e., pH, stoichiometry, and temperature on potassium recovery performance. Results indicated that process performance as well as type of solid phases co-precipitated with K-struvite were closely related to initial potassium concentration, pH, and reaction stoichiometry. At pH 10, the potassium recovery efficiency was maximized up to 87% by application of 100% excess dose of Mg and P for both synthetic samples and synthetic human urine solution. On the other hand, application of excess dose of K did not provide any improvement in K recovery efficiency. The effect of temperature on solubility of K-struvite was insignificant at the temperature range of 24–90◦ C. Solid phase analyses confirmed that K-struvite was co-precipitated with either Mg3 (PO4)2, MgNaPO4·7H2 O, or MgHPO4·7H2 O depending on pH and stoichiometry instead of a pure compound.

AB - The impact of nutrients on the environment, particularly on water bodies, has led to extensive studies for nutrient control. Within this context, studies have been focused on source separation of human urine from domestic wastewater to recover nutrients. Potassium is one of the most important components of human urine. However, data on potassium removal or recovery are quite limited except for some indirect information through use of zeolites for mostly ammonia removal. Potassium struvite or K-struvite (MgKPO4·6H2 O) is a sparingly soluble salt belonging to the struvite family that has the potential of being used as a means of potassium and phosphate recovery from segregated human urine. This study aimed to assess the potential of K-struvite precipitation for control and recovery of nutrients. Within this context, K-struvite precipitation experiments were performed on both synthetically prepared samples and synthetic human urine solution to determine effect of operation parameters i.e., pH, stoichiometry, and temperature on potassium recovery performance. Results indicated that process performance as well as type of solid phases co-precipitated with K-struvite were closely related to initial potassium concentration, pH, and reaction stoichiometry. At pH 10, the potassium recovery efficiency was maximized up to 87% by application of 100% excess dose of Mg and P for both synthetic samples and synthetic human urine solution. On the other hand, application of excess dose of K did not provide any improvement in K recovery efficiency. The effect of temperature on solubility of K-struvite was insignificant at the temperature range of 24–90◦ C. Solid phase analyses confirmed that K-struvite was co-precipitated with either Mg3 (PO4)2, MgNaPO4·7H2 O, or MgHPO4·7H2 O depending on pH and stoichiometry instead of a pure compound.

KW - Human urine

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KW - Operation parameters

KW - Solid phases

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DO - 10.3390/su14031082

M3 - Article

AN - SCOPUS:85123021613

SN - 2071-1050

VL - 14

JO - Sustainability (Switzerland)

JF - Sustainability (Switzerland)

IS - 3

M1 - 1082

ER -

Assessment of K-Struvite Precipitation as a Means of Nutrient Recovery from Source Separated Human Urine

Abstract

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Keywords

UN SDGs

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