Optimization of wet acid phosphorus extraction from sewage sludge ash: Assessment of main influencing factors using an empirical model

This research investigates the primary factor influencing the phosphorus extraction efficiency (PEE) from incinerated sewage sludge ash (ISSA) using hydrochloric acid (HCl) as the extracting agent. A comprehensive database, comprising both literature and new experimental data, was developed to suppo...

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Main Authors: Hiep Le, Isabell Allwicher, Sarah Müller, David Montag, Thomas Wintgens
Format: Article
Language:English
Published: Elsevier 2025-12-01
Series:Water Research X
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Online Access:http://www.sciencedirect.com/science/article/pii/S2589914725000519
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author Hiep Le
Isabell Allwicher
Sarah Müller
David Montag
Thomas Wintgens
author_facet Hiep Le
Isabell Allwicher
Sarah Müller
David Montag
Thomas Wintgens
author_sort Hiep Le
collection DOAJ
description This research investigates the primary factor influencing the phosphorus extraction efficiency (PEE) from incinerated sewage sludge ash (ISSA) using hydrochloric acid (HCl) as the extracting agent. A comprehensive database, comprising both literature and new experimental data, was developed to support the creation of a robust regression model. Based on 152 data sets, this model showed a high coefficient of determination (R² = 0.86), indicating a solid fit. Key findings revealed that the acid concentration (CHCl) had the most significant effect on PEE, followed by the liquid-to-solid ratio (L/S) and contact time (t). The model's predictive accuracy was validated with an R² of 0.75 and a Pearson correlation (r) of 0.96, confirming its reliability. The model effectively predicts PEE for ISSA with moderate calcium content (6–12 %) and offers valuable insights into the process, providing guidelines for optimizing the configuration of process parameters. Optimal conditions for achieving high PEE (> 80 %) with acceptable acid costs (0.30–0.35 €/kg Pextracted) are expected from an extraction variable (X) of 3.8 and at a moderate CHCl (3–4 mol/L) & L/S ratio (2–3 L/kg). Still, the model's applicability is limited by the quality of the data, particularly for ashes with high calcium content. Further research is required to expand the database and enhance model accuracy, particularly for optimizing the phosphorus recovery process using wet acid extraction at an industrial scale.
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issn 2589-9147
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spelling doaj-art-314c215bc98b414395d372206059eaed2025-08-20T03:49:46ZengElsevierWater Research X2589-91472025-12-012910035210.1016/j.wroa.2025.100352Optimization of wet acid phosphorus extraction from sewage sludge ash: Assessment of main influencing factors using an empirical modelHiep Le0Isabell Allwicher1Sarah Müller2David Montag3Thomas Wintgens4Institute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1 52074 Aachen, GermanyInstitute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1 52074 Aachen, GermanyInstitute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1 52074 Aachen, GermanyInstitute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1 52074 Aachen, GermanyCorresponding author.; Institute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1 52074 Aachen, GermanyThis research investigates the primary factor influencing the phosphorus extraction efficiency (PEE) from incinerated sewage sludge ash (ISSA) using hydrochloric acid (HCl) as the extracting agent. A comprehensive database, comprising both literature and new experimental data, was developed to support the creation of a robust regression model. Based on 152 data sets, this model showed a high coefficient of determination (R² = 0.86), indicating a solid fit. Key findings revealed that the acid concentration (CHCl) had the most significant effect on PEE, followed by the liquid-to-solid ratio (L/S) and contact time (t). The model's predictive accuracy was validated with an R² of 0.75 and a Pearson correlation (r) of 0.96, confirming its reliability. The model effectively predicts PEE for ISSA with moderate calcium content (6–12 %) and offers valuable insights into the process, providing guidelines for optimizing the configuration of process parameters. Optimal conditions for achieving high PEE (> 80 %) with acceptable acid costs (0.30–0.35 €/kg Pextracted) are expected from an extraction variable (X) of 3.8 and at a moderate CHCl (3–4 mol/L) & L/S ratio (2–3 L/kg). Still, the model's applicability is limited by the quality of the data, particularly for ashes with high calcium content. Further research is required to expand the database and enhance model accuracy, particularly for optimizing the phosphorus recovery process using wet acid extraction at an industrial scale.http://www.sciencedirect.com/science/article/pii/S2589914725000519Phosphorus recoverySewage sludge ashWet acid extractionEmpirical modelProcess optimization
spellingShingle Hiep Le
Isabell Allwicher
Sarah Müller
David Montag
Thomas Wintgens
Optimization of wet acid phosphorus extraction from sewage sludge ash: Assessment of main influencing factors using an empirical model
Water Research X
Phosphorus recovery
Sewage sludge ash
Wet acid extraction
Empirical model
Process optimization
title Optimization of wet acid phosphorus extraction from sewage sludge ash: Assessment of main influencing factors using an empirical model
title_full Optimization of wet acid phosphorus extraction from sewage sludge ash: Assessment of main influencing factors using an empirical model
title_fullStr Optimization of wet acid phosphorus extraction from sewage sludge ash: Assessment of main influencing factors using an empirical model
title_full_unstemmed Optimization of wet acid phosphorus extraction from sewage sludge ash: Assessment of main influencing factors using an empirical model
title_short Optimization of wet acid phosphorus extraction from sewage sludge ash: Assessment of main influencing factors using an empirical model
title_sort optimization of wet acid phosphorus extraction from sewage sludge ash assessment of main influencing factors using an empirical model
topic Phosphorus recovery
Sewage sludge ash
Wet acid extraction
Empirical model
Process optimization
url http://www.sciencedirect.com/science/article/pii/S2589914725000519
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