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Michael Hupfer - One of the best experts on this subject based on the ideXlab platform.
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The occurrence, identification and environmental relevance of Vivianite in waterlogged soils and aquatic sediments
Earth-Science Reviews, 2016Co-Authors: Matthias Rothe, Andreas Kleeberg, Michael HupferAbstract:Abstract In this article, we review the nature, occurrence and environmental relevance of the authigenic ferrous iron phosphate mineral Vivianite (Fe 3 (PO 4 ) 2 ·8H 2 O) in waterlogged soils and aquatic sediments. We critically discuss existing work from freshwater and marine systems, laboratory studies and microbial batch culture experiments aiming to deduce common characteristics of the mineral's occurrence, and the processes governing its formation. Vivianite regularly occurs in close association with organic remains in iron-rich sediments. Simultaneously, it is a biogenic mineral product of metal reducing bacteria. These findings suggest that Vivianite nucleation in natural systems is directed by the activity of such bacteria and crystal growth is particularly favoured within protected microzones. Taking into account recent findings from coastal marine sediments where Vivianite authigenesis has been shown to be coupled to the anaerobic oxidation of methane, small-scale microbially mediated reactions appear to be crucial for the formation of Vivianite. Small-scale heterogeneity within the sediment matrix may also explain why saturation calculations based upon bulk pore water constitutions often fail to accurately predict the occurrence of the mineral. Vivianite is not restricted to a specific trophic state of a system. The mineral forms in oligotrophic- as well as in eutrophic waters. However, depending on the iron inventory, the production, supply and degradation of organic matter determine the relative contribution of iron sulphide formation to the iron pool, and the concentration of inorganic phosphate and Fe 2 + in pore waters. Thus, Vivianite authigenesis is also governed by bulk chemical conditions such as the rate of sulphide formation relative to that of Fe 2 + production. This situation allows stimulation of Vivianite formation by iron supplementation aimed at restoring eutrophic lakes. Recent results from coastal marine sediments suggest that Vivianite authigenesis is of significance for P burial in the marine realm. Vivianite authigenesis is likely important at the global scale, but has so far largely been ignored.
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Sedimentary Sulphur:Iron Ratio Indicates Vivianite Occurrence: A Study from Two Contrasting Freshwater Systems.
PloS one, 2015Co-Authors: Matthias Rothe, Andreas Kleeberg, Björn Grüneberg, Kurt Friese, Manuel Pérez-mayo, Michael HupferAbstract:An increasing number of studies constrain the importance of iron for the long-term retention of phosphorus (P) under anoxic conditions, i.e. the formation of reduced iron phosphate minerals such as Vivianite (Fe3(PO4)2⋅8H2O). Much remains unknown about Vivianite formation, the factors controlling its occurrence, and its relevance for P burial during early sediment diagenesis. To study the occurrence of Vivianite and to assess its relevance for P binding, surface sediments of two hydrologically contrasting waters were analysed by heavy-liquid separation and subsequent powder X-ray diffraction. In Lake Arendsee, Vivianite was present in deeper sediment horizons and not in the uppermost layers with a sharp transition between Vivianite and non-Vivianite bearing layers. In contrast, in lowland river Lower Havel Vivianite was present in the upper sediment layers and not in deeper horizons with a gradual transition between non-Vivianite and Vivianite bearing layers. In both waters, Vivianite occurrence was accompanied by the presence of pyrite (FeS2). Vivianite formation was favoured by an elevated iron availability through a lower degree of sulphidisation and was present at a molar ratio of total sulphur to reactive iron smaller than 1.1, only. A longer lasting burden of sediments by organic matter, i.e. due to eutrophication, favours the release of sulphides, and the formation of insoluble iron sulphides leading to a lack of available iron and to less or no Vivianite formation. This weakening in sedimentary P retention, representing a negative feedback mechanism (P release) in terms of water quality, could be partly compensated by harmless Fe amendments.
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evidence for Vivianite formation and its contribution to long term phosphorus retention in a recent lake sediment a novel analytical approach
Biogeosciences, 2014Co-Authors: Matthias Rothe, Andreas Kleeberg, T. Frederichs, M. Eder, Michael HupferAbstract:Abstract. Vivianite, Fe3(PO4)2 · 8 H2O, is a ferrous iron phosphate mineral which forms in waterlogged soils and sediments. The phosphorus (P) bound in its crystal lattice is considered to be immobilised because Vivianite is stable under anoxic, reducing, sedimentary conditions. Thus, Vivianite formation can make a major contribution to P retention during early diagenesis. Much remains unknown about Vivianite in sediments, because technical challenges have rendered direct identification and quantification difficult. To identify Vivianite and assess its significance for P burial during early diagenesis we studied the consequences of a 1992/1993 in-lake application of FeCl3 and Fe(OH)3 aimed at restoring Lake Gros-Glienicke (Berlin, Germany). In a novel approach, we firstly applied a heavy-liquid separation to the iron-rich surface sediments which allowed direct identification of Vivianite by X-ray diffraction in the high-density (ρ > 2.3 g cm−3) sediment fraction. Secondly, we assessed the contribution of Vivianite to P retention, combining results from chemical digestion with magnetic susceptibility data derived from magnetic hysteresis measurements. Scanning electron microscopy revealed that the dark blue spherical Vivianite nodules were 40–180 μm in diameter, and formed of platy- and needle-shaped crystal aggregates. Although equilibrium calculations indicated supersaturation of Vivianite throughout the upper 30 cm of the sediment, the Vivianite deposits were homogeneously distributed within, and restricted to, the upper 23 cm only. Thus, supersaturated pore water alone cannot serve as a reliable predictor for the in situ formation of Vivianite. In Lake Gros -Glienicke, Vivianite formation continues to be triggered by the artificial iron amendment more than 20 yr ago, significantly contributing to P retention in surface sediments.
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Evidence for Vivianite formation and its contribution to long-term phosphorus retention in a recent lake sediment: a novel analytical approach
Biogeosciences, 2014Co-Authors: Matthias Rothe, Andreas Kleeberg, T. Frederichs, M. Eder, Michael HupferAbstract:Vivianite, Fe3(PO4)2 · 8H2O, is a ferrous iron phosphate mineral which forms in waterlogged soils and sed- iments. The phosphorus (P) bound in its crystal lattice is considered to be immobilised because Vivianite is stable un- der anoxic, reducing, sedimentary conditions. Thus, Vivianite formation can make a major contribution to P retention dur- ing early diagenesis. Much remains unknown about Vivianite in sediments, because technical challenges have rendered di- rect identification and quantification difficult. To identify vi- vianite and assess its significance for P burial during early di- agenesis we studied the consequences of a 1992/1993 in-lake application of FeCl3 and Fe(OH)3 aimed at restoring Lake Gros-Glienicke (Berlin, Germany). In a novel approach, we firstly applied a heavy-liquid separation to the iron-rich sur- face sediments which allowed direct identification of vivian- ite by X-ray diffraction in the high-density ( >
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Evidence for Vivianite formation and its contribution to long-term phosphorus retention in a recent lake sediment: a novel analytical approach
2014Co-Authors: M. Rothe, Andreas Kleeberg, T. Frederichs, M. Eder, Michael HupferAbstract:Abstract. Vivianite, Fe3(PO4)2 × 8 H2O, is a ferrous iron phosphate mineral which forms in waterlogged soils and sediments. The phosphorus (P) bound in its crystal lattice is considered to be immobilised because Vivianite is stable under anoxic, reducing, sedimentary conditions. Thus, Vivianite formation can make a major contribution to P retention during early diagenesis. Much remains unknown about Vivianite in sediments, because technical challenges have rendered direct identification and quantification difficult. To identify Vivianite and assess its significance for P burial during early diagenesis we studied the consequences of a 1992/1993 in-lake application of FeCl3 and Fe(OH)3 aimed at restoring Lake Groß-Glienicke (Berlin, Germany). In a novel approach, we firstly applied a heavy-liquid separation to the iron-rich surface sediments which allowed direct identification of Vivianite by X-ray diffraction in the high-density (ρ > 2.3 g cm−3) sediment fraction. Secondly, we assessed the contribution of Vivianite to P retention, combining results from chemical digestion with magnetic susceptibility data derived from magnetic hysteresis measurements. Scanning electron microscopy revealed that the dark blue spherical Vivianite nodules were 40–180 μm in diameter, and formed of platy- and needle shaped crystal aggregates. Although equilibrium calculations indicated supersaturation of Vivianite throughout the upper 30 cm of the sediment, the Vivianite deposits were homogeneously distributed within, and restricted to, the upper 23 cm only. Thus, supersaturated pore water alone cannot serve as a reliable predictor for the in-situ formation of Vivianite. In Lake Groß -Glienicke, Vivianite formation continues to be triggered by the artificial iron amendment more than 20 years ago, significantly contributing to P retention in surface sediments.
M C M Van Loosdrecht - One of the best experts on this subject based on the ideXlab platform.
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Vivianite scaling in wastewater treatment plants occurrence formation mechanisms and mitigation solutions
Water Research, 2021Co-Authors: T Prot, A I Dugulan, K Goubitz, Leon Korving, M C M Van LoosdrechtAbstract:Abstract The presence of soluble iron and phosphorus in wastewater sludge can lead to Vivianite scaling. This problem is not often reported in literature, most likely due to the difficult identification and quantification of this mineral. It is usually present as a hard and blue deposit that can also be brown or black depending on its composition and location. From samples and information gathered in 14 wastewater treatment plants worldwide, it became clear that Vivianite scaling is common and can cause operational issues. Vivianite scaling mainly occurred in 3 zones, for which formation hypotheses were discussed. Firstly, iron reduction seems to be the trigger for scaling in anaerobic zones like sludge pipes, mainly after sludge thickening. Secondly, pH increase was evaluated to be the major cause for the formation of a mixed scaling (a majority of oxidized Vivianite with some iron hydroxides) around dewatering centrifuges of undigested sludge. Thirdly, the temperature dependence of Vivianite solubility appears to be the driver for Vivianite deposition in heat exchanger around mesophilic digesters (37°C), while higher temperatures potentially aggravate the phenomenon, for instance in thermophilic digesters. Mitigation solutions like the use of buffer tanks or steam injections are discussed. Finally, best practices for safe mixing of sludges with each other are proposed, since poor admixing can contribute to scaling aggravation. The relevance of this study lays in the occurrence of ironphosphate scaling, while the use of iron coagulants will probably increase in the future to meet more stringent phosphorus discharge limits.
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full scale increased iron dosage to stimulate the formation of Vivianite and its recovery from digested sewage sludge
Water Research, 2020Co-Authors: T Prot, A I Dugulan, K Goubitz, Leon Korving, W Wijdeveld, Ekua L Eshun, M C M Van LoosdrechtAbstract:Abstract The recovery of phosphorus from secondary sources like sewage sludge is essential in a world suffering from resources depletion. Recent studies have demonstrated that phosphorus can be magnetically recovered as Vivianite (Fe(II)3(PO4)2∗8H2O) from the digested sludge (DS) of Waste Water Treatment Plants (WWTP) dosing iron. To study the production of Vivianite in digested sludge, the quantity of Fe dosed at the WWTP of Nieuwveer (The Netherlands) was increased (from 0.83 to 1.53 kg Fe/kg P in the influent), and the possible benefits for the functioning of the WWTP were evaluated. Higher Fe dosing is not only relevant for P-recovery, but also for maximal recovery of organics from influent for e.g. biogas production. The share of phosphorus present as Vivianite in the DS increased from 20% to 50% after the increase in Fe dosing, making more phosphorus available for future magnetic recovery. This increase was directly proportional to the increase of Fe in DS, suggesting that Vivianite could be favored not only thermodynamically, but also kinetically. Interestingly, analyses suggest that several types of Vivianite are formed in the WWTP, and could differ in their purity, oxidation state or crystallinity. These differences could have an impact on the subsequent magnetic separation. Following the Fe dosing increase, P in the effluent and H2S in the biogas both decreased: 1.28 to 0.42 ppm for P and 26 to 8 ppm for H2S. No negative impact on the nitrogen removal, biogas production, COD removal or dewaterability was observed. Since quantification of Vivianite in DS is complicated, previous studies were reviewed and we proposed a more accurate Mossbauer spectroscopy analysis and fitting for sludge samples. This study is important from a P recovery point of view, but also because iron addition can play a crucial role in future resource recovery wastewater facilities.
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Vivianite as the main phosphate mineral in digested sewage sludge and its role for phosphate recovery
Water Research, 2018Co-Authors: Philipp Wilfert, A I Dugulan, K Goubitz, Leon Korving, G J Witkamp, M C M Van LoosdrechtAbstract:Phosphate recovery from sewage sludge is essential in a circular economy. Currently, the main focus in centralized municipal wastewater treatment plants (MWTPs) lies on struvite recovery routes, land application of sludge or on technologies that rely on sludge incineration. These routes have several disadvantages. Our study shows that the mineral Vivianite, Fe2(PO4)3 × 8H2O, is present in digested sludge and can be the major form of phosphate in the sludge. Thus, we suggest Vivianite can be the nucleus for alternative phosphate recovery options. Excess and digested sewage sludge was sampled from full-scale MWTPs and analysed using x-ray diffraction (XRD), conventional scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), environmental SEM-EDX (eSEM-EDX) and Mossbauer spectroscopy. Vivianite was observed in all plants where iron was used for phosphate removal. In excess sludge before the anaerobic digestion, ferrous iron dominated the iron pool (≥50%) as shown by Mossbauer spectroscopy. XRD and Mossbauer spectroscopy showed no clear correlation between Vivianite bound phosphate versus the iron content in excess sludge. In digested sludge, ferrous iron was the dominant iron form (>85%). Phosphate bound in Vivianite increased with the iron content of the digested sludge but levelled off at high iron levels. 70-90% of all phosphate was bound in Vivianite in the sludge with the highest iron content (molar Fe:P = 2.5). The quantification of Vivianite was difficult and bears some uncertainty probably because of the presence of impure Vivianite as indicated by SEM-EDX. eSEM-EDX indicates that the Vivianite occurs as relatively small (20-100 μm) but free particles. We envisage very efficient phosphate recovery technologies that separate these particles based on their magnetic properties from the complex sludge matrix.
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Vivianite as an important iron phosphate precipitate in sewage treatment plants.
Water research, 2016Co-Authors: Philipp Wilfert, A I Dugulan, K Goubitz, Leon Korving, A. Mandalidis, Hardy Temmink, Geert-jan Witkamp, M C M Van LoosdrechtAbstract:Iron is an important element for modern sewage treatment, inter alia to remove phosphorus from sewage. However, phosphorus recovery from iron phosphorus containing sewage sludge, without incineration, is not yet economical. We believe, increasing the knowledge about iron-phosphorus speciation in sewage sludge can help to identify new routes for phosphorus recovery. Surplus and digested sludge of two sewage treatment plants was investigated. The plants relied either solely on iron based phosphorus removal or on biological phosphorus removal supported by iron dosing. Mossbauer spectroscopy showed that Vivianite and pyrite were the dominating iron compounds in the surplus and anaerobically digested sludge solids in both plants. Mossbauer spectroscopy and XRD suggested that Vivianite bound phosphorus made up between 10 and 30% (in the plant relying mainly on biological removal) and between 40 and 50% of total phosphorus (in the plant that relies on iron based phosphorus removal). Furthermore, Mossbauer spectroscopy indicated that none of the samples contained a significant amount of Fe(III), even though aerated treatment stages existed and although besides Fe(II) also Fe(III) was dosed. We hypothesize that chemical/microbial Fe(III) reduction in the treatment lines is relatively quick and triggers Vivianite formation. Once formed, Vivianite may endure oxygenated treatment zones due to slow oxidation kinetics and due to oxygen diffusion limitations into sludge flocs. These results indicate that Vivianite is the major iron phosphorus compound in sewage treatment plants with moderate iron dosing. We hypothesize that Vivianite is dominating in most plants where iron is dosed for phosphorus removal which could offer new routes for phosphorus recovery.
Matthias Rothe - One of the best experts on this subject based on the ideXlab platform.
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The occurrence, identification and environmental relevance of Vivianite in waterlogged soils and aquatic sediments
Earth-Science Reviews, 2016Co-Authors: Matthias Rothe, Andreas Kleeberg, Michael HupferAbstract:Abstract In this article, we review the nature, occurrence and environmental relevance of the authigenic ferrous iron phosphate mineral Vivianite (Fe 3 (PO 4 ) 2 ·8H 2 O) in waterlogged soils and aquatic sediments. We critically discuss existing work from freshwater and marine systems, laboratory studies and microbial batch culture experiments aiming to deduce common characteristics of the mineral's occurrence, and the processes governing its formation. Vivianite regularly occurs in close association with organic remains in iron-rich sediments. Simultaneously, it is a biogenic mineral product of metal reducing bacteria. These findings suggest that Vivianite nucleation in natural systems is directed by the activity of such bacteria and crystal growth is particularly favoured within protected microzones. Taking into account recent findings from coastal marine sediments where Vivianite authigenesis has been shown to be coupled to the anaerobic oxidation of methane, small-scale microbially mediated reactions appear to be crucial for the formation of Vivianite. Small-scale heterogeneity within the sediment matrix may also explain why saturation calculations based upon bulk pore water constitutions often fail to accurately predict the occurrence of the mineral. Vivianite is not restricted to a specific trophic state of a system. The mineral forms in oligotrophic- as well as in eutrophic waters. However, depending on the iron inventory, the production, supply and degradation of organic matter determine the relative contribution of iron sulphide formation to the iron pool, and the concentration of inorganic phosphate and Fe 2 + in pore waters. Thus, Vivianite authigenesis is also governed by bulk chemical conditions such as the rate of sulphide formation relative to that of Fe 2 + production. This situation allows stimulation of Vivianite formation by iron supplementation aimed at restoring eutrophic lakes. Recent results from coastal marine sediments suggest that Vivianite authigenesis is of significance for P burial in the marine realm. Vivianite authigenesis is likely important at the global scale, but has so far largely been ignored.
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Sedimentary Sulphur:Iron Ratio Indicates Vivianite Occurrence: A Study from Two Contrasting Freshwater Systems.
PloS one, 2015Co-Authors: Matthias Rothe, Andreas Kleeberg, Björn Grüneberg, Kurt Friese, Manuel Pérez-mayo, Michael HupferAbstract:An increasing number of studies constrain the importance of iron for the long-term retention of phosphorus (P) under anoxic conditions, i.e. the formation of reduced iron phosphate minerals such as Vivianite (Fe3(PO4)2⋅8H2O). Much remains unknown about Vivianite formation, the factors controlling its occurrence, and its relevance for P burial during early sediment diagenesis. To study the occurrence of Vivianite and to assess its relevance for P binding, surface sediments of two hydrologically contrasting waters were analysed by heavy-liquid separation and subsequent powder X-ray diffraction. In Lake Arendsee, Vivianite was present in deeper sediment horizons and not in the uppermost layers with a sharp transition between Vivianite and non-Vivianite bearing layers. In contrast, in lowland river Lower Havel Vivianite was present in the upper sediment layers and not in deeper horizons with a gradual transition between non-Vivianite and Vivianite bearing layers. In both waters, Vivianite occurrence was accompanied by the presence of pyrite (FeS2). Vivianite formation was favoured by an elevated iron availability through a lower degree of sulphidisation and was present at a molar ratio of total sulphur to reactive iron smaller than 1.1, only. A longer lasting burden of sediments by organic matter, i.e. due to eutrophication, favours the release of sulphides, and the formation of insoluble iron sulphides leading to a lack of available iron and to less or no Vivianite formation. This weakening in sedimentary P retention, representing a negative feedback mechanism (P release) in terms of water quality, could be partly compensated by harmless Fe amendments.
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evidence for Vivianite formation and its contribution to long term phosphorus retention in a recent lake sediment a novel analytical approach
Biogeosciences, 2014Co-Authors: Matthias Rothe, Andreas Kleeberg, T. Frederichs, M. Eder, Michael HupferAbstract:Abstract. Vivianite, Fe3(PO4)2 · 8 H2O, is a ferrous iron phosphate mineral which forms in waterlogged soils and sediments. The phosphorus (P) bound in its crystal lattice is considered to be immobilised because Vivianite is stable under anoxic, reducing, sedimentary conditions. Thus, Vivianite formation can make a major contribution to P retention during early diagenesis. Much remains unknown about Vivianite in sediments, because technical challenges have rendered direct identification and quantification difficult. To identify Vivianite and assess its significance for P burial during early diagenesis we studied the consequences of a 1992/1993 in-lake application of FeCl3 and Fe(OH)3 aimed at restoring Lake Gros-Glienicke (Berlin, Germany). In a novel approach, we firstly applied a heavy-liquid separation to the iron-rich surface sediments which allowed direct identification of Vivianite by X-ray diffraction in the high-density (ρ > 2.3 g cm−3) sediment fraction. Secondly, we assessed the contribution of Vivianite to P retention, combining results from chemical digestion with magnetic susceptibility data derived from magnetic hysteresis measurements. Scanning electron microscopy revealed that the dark blue spherical Vivianite nodules were 40–180 μm in diameter, and formed of platy- and needle-shaped crystal aggregates. Although equilibrium calculations indicated supersaturation of Vivianite throughout the upper 30 cm of the sediment, the Vivianite deposits were homogeneously distributed within, and restricted to, the upper 23 cm only. Thus, supersaturated pore water alone cannot serve as a reliable predictor for the in situ formation of Vivianite. In Lake Gros -Glienicke, Vivianite formation continues to be triggered by the artificial iron amendment more than 20 yr ago, significantly contributing to P retention in surface sediments.
-
Evidence for Vivianite formation and its contribution to long-term phosphorus retention in a recent lake sediment: a novel analytical approach
Biogeosciences, 2014Co-Authors: Matthias Rothe, Andreas Kleeberg, T. Frederichs, M. Eder, Michael HupferAbstract:Vivianite, Fe3(PO4)2 · 8H2O, is a ferrous iron phosphate mineral which forms in waterlogged soils and sed- iments. The phosphorus (P) bound in its crystal lattice is considered to be immobilised because Vivianite is stable un- der anoxic, reducing, sedimentary conditions. Thus, Vivianite formation can make a major contribution to P retention dur- ing early diagenesis. Much remains unknown about Vivianite in sediments, because technical challenges have rendered di- rect identification and quantification difficult. To identify vi- vianite and assess its significance for P burial during early di- agenesis we studied the consequences of a 1992/1993 in-lake application of FeCl3 and Fe(OH)3 aimed at restoring Lake Gros-Glienicke (Berlin, Germany). In a novel approach, we firstly applied a heavy-liquid separation to the iron-rich sur- face sediments which allowed direct identification of vivian- ite by X-ray diffraction in the high-density ( >
Leon Korving - One of the best experts on this subject based on the ideXlab platform.
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Vivianite scaling in wastewater treatment plants occurrence formation mechanisms and mitigation solutions
Water Research, 2021Co-Authors: T Prot, A I Dugulan, K Goubitz, Leon Korving, M C M Van LoosdrechtAbstract:Abstract The presence of soluble iron and phosphorus in wastewater sludge can lead to Vivianite scaling. This problem is not often reported in literature, most likely due to the difficult identification and quantification of this mineral. It is usually present as a hard and blue deposit that can also be brown or black depending on its composition and location. From samples and information gathered in 14 wastewater treatment plants worldwide, it became clear that Vivianite scaling is common and can cause operational issues. Vivianite scaling mainly occurred in 3 zones, for which formation hypotheses were discussed. Firstly, iron reduction seems to be the trigger for scaling in anaerobic zones like sludge pipes, mainly after sludge thickening. Secondly, pH increase was evaluated to be the major cause for the formation of a mixed scaling (a majority of oxidized Vivianite with some iron hydroxides) around dewatering centrifuges of undigested sludge. Thirdly, the temperature dependence of Vivianite solubility appears to be the driver for Vivianite deposition in heat exchanger around mesophilic digesters (37°C), while higher temperatures potentially aggravate the phenomenon, for instance in thermophilic digesters. Mitigation solutions like the use of buffer tanks or steam injections are discussed. Finally, best practices for safe mixing of sludges with each other are proposed, since poor admixing can contribute to scaling aggravation. The relevance of this study lays in the occurrence of ironphosphate scaling, while the use of iron coagulants will probably increase in the future to meet more stringent phosphorus discharge limits.
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full scale increased iron dosage to stimulate the formation of Vivianite and its recovery from digested sewage sludge
Water Research, 2020Co-Authors: T Prot, A I Dugulan, K Goubitz, Leon Korving, W Wijdeveld, Ekua L Eshun, M C M Van LoosdrechtAbstract:Abstract The recovery of phosphorus from secondary sources like sewage sludge is essential in a world suffering from resources depletion. Recent studies have demonstrated that phosphorus can be magnetically recovered as Vivianite (Fe(II)3(PO4)2∗8H2O) from the digested sludge (DS) of Waste Water Treatment Plants (WWTP) dosing iron. To study the production of Vivianite in digested sludge, the quantity of Fe dosed at the WWTP of Nieuwveer (The Netherlands) was increased (from 0.83 to 1.53 kg Fe/kg P in the influent), and the possible benefits for the functioning of the WWTP were evaluated. Higher Fe dosing is not only relevant for P-recovery, but also for maximal recovery of organics from influent for e.g. biogas production. The share of phosphorus present as Vivianite in the DS increased from 20% to 50% after the increase in Fe dosing, making more phosphorus available for future magnetic recovery. This increase was directly proportional to the increase of Fe in DS, suggesting that Vivianite could be favored not only thermodynamically, but also kinetically. Interestingly, analyses suggest that several types of Vivianite are formed in the WWTP, and could differ in their purity, oxidation state or crystallinity. These differences could have an impact on the subsequent magnetic separation. Following the Fe dosing increase, P in the effluent and H2S in the biogas both decreased: 1.28 to 0.42 ppm for P and 26 to 8 ppm for H2S. No negative impact on the nitrogen removal, biogas production, COD removal or dewaterability was observed. Since quantification of Vivianite in DS is complicated, previous studies were reviewed and we proposed a more accurate Mossbauer spectroscopy analysis and fitting for sludge samples. This study is important from a P recovery point of view, but also because iron addition can play a crucial role in future resource recovery wastewater facilities.
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magnetic separation and characterization of Vivianite from digested sewage sludge
Separation and Purification Technology, 2019Co-Authors: T Prot, Philipp Wilfert, A I Dugulan, K Goubitz, Leon Korving, Van Hoa Nguyen, Dick De Ridder, Peter Carlo Rem, A Bouderbala, G J WitkampAbstract:To prevent eutrophication of surface water, phosphate needs to be removed from sewage. Iron (Fe) dosing is commonly used to achieve this goal either as the main strategy or in support of biological removal. Vivianite (Fe(II) 3 (PO 4 ) 2 * 8H 2 O) plays a crucial role in capturing the phosphate, and if enough iron is present in the sludge after anaerobic digestion, 70–90% of total phosphorus (P) can be bound in Vivianite. Based on its paramagnetism and inspired by technologies used in the mining industry, a magnetic separation procedure has been developed. Two digested sludges from sewage treatment plants using Chemical Phosphorus Removal were processed with a lab-scale Jones magnetic separator with an emphasis on the characterization of the recovered Vivianite and the P-rich caustic solution. The recovered fractions were analyzed with various analytical techniques (e.g., ICP-OES, TG-DSC-MS, XRD and Mossbauer spectroscopy). The magnetic separation showed a concentration factor for phosphorus and iron of 2–3. The separated fractions consist of 52–62% of Vivianite, 20% of organic matter, less than 10% of quartz and a small quantity of siderite. More than 80% of the P in the recovered Vivianite mixture can be released and thus recovered via an alkaline treatment while the resulting iron oxide has the potential to be reused. Moreover, the trace elements in the P-rich caustic solution meet the future legislation for recovered phosphorus salts and are comparable to the usual content in Phosphate rock. The efficiency of the magnetic separation and the advantages of its implementation in WWTP are also discussed in this paper.
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Vivianite as the main phosphate mineral in digested sewage sludge and its role for phosphate recovery
Water Research, 2018Co-Authors: Philipp Wilfert, A I Dugulan, K Goubitz, Leon Korving, G J Witkamp, M C M Van LoosdrechtAbstract:Phosphate recovery from sewage sludge is essential in a circular economy. Currently, the main focus in centralized municipal wastewater treatment plants (MWTPs) lies on struvite recovery routes, land application of sludge or on technologies that rely on sludge incineration. These routes have several disadvantages. Our study shows that the mineral Vivianite, Fe2(PO4)3 × 8H2O, is present in digested sludge and can be the major form of phosphate in the sludge. Thus, we suggest Vivianite can be the nucleus for alternative phosphate recovery options. Excess and digested sewage sludge was sampled from full-scale MWTPs and analysed using x-ray diffraction (XRD), conventional scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), environmental SEM-EDX (eSEM-EDX) and Mossbauer spectroscopy. Vivianite was observed in all plants where iron was used for phosphate removal. In excess sludge before the anaerobic digestion, ferrous iron dominated the iron pool (≥50%) as shown by Mossbauer spectroscopy. XRD and Mossbauer spectroscopy showed no clear correlation between Vivianite bound phosphate versus the iron content in excess sludge. In digested sludge, ferrous iron was the dominant iron form (>85%). Phosphate bound in Vivianite increased with the iron content of the digested sludge but levelled off at high iron levels. 70-90% of all phosphate was bound in Vivianite in the sludge with the highest iron content (molar Fe:P = 2.5). The quantification of Vivianite was difficult and bears some uncertainty probably because of the presence of impure Vivianite as indicated by SEM-EDX. eSEM-EDX indicates that the Vivianite occurs as relatively small (20-100 μm) but free particles. We envisage very efficient phosphate recovery technologies that separate these particles based on their magnetic properties from the complex sludge matrix.
-
Vivianite as an important iron phosphate precipitate in sewage treatment plants.
Water research, 2016Co-Authors: Philipp Wilfert, A I Dugulan, K Goubitz, Leon Korving, A. Mandalidis, Hardy Temmink, Geert-jan Witkamp, M C M Van LoosdrechtAbstract:Iron is an important element for modern sewage treatment, inter alia to remove phosphorus from sewage. However, phosphorus recovery from iron phosphorus containing sewage sludge, without incineration, is not yet economical. We believe, increasing the knowledge about iron-phosphorus speciation in sewage sludge can help to identify new routes for phosphorus recovery. Surplus and digested sludge of two sewage treatment plants was investigated. The plants relied either solely on iron based phosphorus removal or on biological phosphorus removal supported by iron dosing. Mossbauer spectroscopy showed that Vivianite and pyrite were the dominating iron compounds in the surplus and anaerobically digested sludge solids in both plants. Mossbauer spectroscopy and XRD suggested that Vivianite bound phosphorus made up between 10 and 30% (in the plant relying mainly on biological removal) and between 40 and 50% of total phosphorus (in the plant that relies on iron based phosphorus removal). Furthermore, Mossbauer spectroscopy indicated that none of the samples contained a significant amount of Fe(III), even though aerated treatment stages existed and although besides Fe(II) also Fe(III) was dosed. We hypothesize that chemical/microbial Fe(III) reduction in the treatment lines is relatively quick and triggers Vivianite formation. Once formed, Vivianite may endure oxygenated treatment zones due to slow oxidation kinetics and due to oxygen diffusion limitations into sludge flocs. These results indicate that Vivianite is the major iron phosphorus compound in sewage treatment plants with moderate iron dosing. We hypothesize that Vivianite is dominating in most plants where iron is dosed for phosphorus removal which could offer new routes for phosphorus recovery.
K Goubitz - One of the best experts on this subject based on the ideXlab platform.
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Vivianite scaling in wastewater treatment plants occurrence formation mechanisms and mitigation solutions
Water Research, 2021Co-Authors: T Prot, A I Dugulan, K Goubitz, Leon Korving, M C M Van LoosdrechtAbstract:Abstract The presence of soluble iron and phosphorus in wastewater sludge can lead to Vivianite scaling. This problem is not often reported in literature, most likely due to the difficult identification and quantification of this mineral. It is usually present as a hard and blue deposit that can also be brown or black depending on its composition and location. From samples and information gathered in 14 wastewater treatment plants worldwide, it became clear that Vivianite scaling is common and can cause operational issues. Vivianite scaling mainly occurred in 3 zones, for which formation hypotheses were discussed. Firstly, iron reduction seems to be the trigger for scaling in anaerobic zones like sludge pipes, mainly after sludge thickening. Secondly, pH increase was evaluated to be the major cause for the formation of a mixed scaling (a majority of oxidized Vivianite with some iron hydroxides) around dewatering centrifuges of undigested sludge. Thirdly, the temperature dependence of Vivianite solubility appears to be the driver for Vivianite deposition in heat exchanger around mesophilic digesters (37°C), while higher temperatures potentially aggravate the phenomenon, for instance in thermophilic digesters. Mitigation solutions like the use of buffer tanks or steam injections are discussed. Finally, best practices for safe mixing of sludges with each other are proposed, since poor admixing can contribute to scaling aggravation. The relevance of this study lays in the occurrence of ironphosphate scaling, while the use of iron coagulants will probably increase in the future to meet more stringent phosphorus discharge limits.
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full scale increased iron dosage to stimulate the formation of Vivianite and its recovery from digested sewage sludge
Water Research, 2020Co-Authors: T Prot, A I Dugulan, K Goubitz, Leon Korving, W Wijdeveld, Ekua L Eshun, M C M Van LoosdrechtAbstract:Abstract The recovery of phosphorus from secondary sources like sewage sludge is essential in a world suffering from resources depletion. Recent studies have demonstrated that phosphorus can be magnetically recovered as Vivianite (Fe(II)3(PO4)2∗8H2O) from the digested sludge (DS) of Waste Water Treatment Plants (WWTP) dosing iron. To study the production of Vivianite in digested sludge, the quantity of Fe dosed at the WWTP of Nieuwveer (The Netherlands) was increased (from 0.83 to 1.53 kg Fe/kg P in the influent), and the possible benefits for the functioning of the WWTP were evaluated. Higher Fe dosing is not only relevant for P-recovery, but also for maximal recovery of organics from influent for e.g. biogas production. The share of phosphorus present as Vivianite in the DS increased from 20% to 50% after the increase in Fe dosing, making more phosphorus available for future magnetic recovery. This increase was directly proportional to the increase of Fe in DS, suggesting that Vivianite could be favored not only thermodynamically, but also kinetically. Interestingly, analyses suggest that several types of Vivianite are formed in the WWTP, and could differ in their purity, oxidation state or crystallinity. These differences could have an impact on the subsequent magnetic separation. Following the Fe dosing increase, P in the effluent and H2S in the biogas both decreased: 1.28 to 0.42 ppm for P and 26 to 8 ppm for H2S. No negative impact on the nitrogen removal, biogas production, COD removal or dewaterability was observed. Since quantification of Vivianite in DS is complicated, previous studies were reviewed and we proposed a more accurate Mossbauer spectroscopy analysis and fitting for sludge samples. This study is important from a P recovery point of view, but also because iron addition can play a crucial role in future resource recovery wastewater facilities.
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magnetic separation and characterization of Vivianite from digested sewage sludge
Separation and Purification Technology, 2019Co-Authors: T Prot, Philipp Wilfert, A I Dugulan, K Goubitz, Leon Korving, Van Hoa Nguyen, Dick De Ridder, Peter Carlo Rem, A Bouderbala, G J WitkampAbstract:To prevent eutrophication of surface water, phosphate needs to be removed from sewage. Iron (Fe) dosing is commonly used to achieve this goal either as the main strategy or in support of biological removal. Vivianite (Fe(II) 3 (PO 4 ) 2 * 8H 2 O) plays a crucial role in capturing the phosphate, and if enough iron is present in the sludge after anaerobic digestion, 70–90% of total phosphorus (P) can be bound in Vivianite. Based on its paramagnetism and inspired by technologies used in the mining industry, a magnetic separation procedure has been developed. Two digested sludges from sewage treatment plants using Chemical Phosphorus Removal were processed with a lab-scale Jones magnetic separator with an emphasis on the characterization of the recovered Vivianite and the P-rich caustic solution. The recovered fractions were analyzed with various analytical techniques (e.g., ICP-OES, TG-DSC-MS, XRD and Mossbauer spectroscopy). The magnetic separation showed a concentration factor for phosphorus and iron of 2–3. The separated fractions consist of 52–62% of Vivianite, 20% of organic matter, less than 10% of quartz and a small quantity of siderite. More than 80% of the P in the recovered Vivianite mixture can be released and thus recovered via an alkaline treatment while the resulting iron oxide has the potential to be reused. Moreover, the trace elements in the P-rich caustic solution meet the future legislation for recovered phosphorus salts and are comparable to the usual content in Phosphate rock. The efficiency of the magnetic separation and the advantages of its implementation in WWTP are also discussed in this paper.
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Vivianite as the main phosphate mineral in digested sewage sludge and its role for phosphate recovery
Water Research, 2018Co-Authors: Philipp Wilfert, A I Dugulan, K Goubitz, Leon Korving, G J Witkamp, M C M Van LoosdrechtAbstract:Phosphate recovery from sewage sludge is essential in a circular economy. Currently, the main focus in centralized municipal wastewater treatment plants (MWTPs) lies on struvite recovery routes, land application of sludge or on technologies that rely on sludge incineration. These routes have several disadvantages. Our study shows that the mineral Vivianite, Fe2(PO4)3 × 8H2O, is present in digested sludge and can be the major form of phosphate in the sludge. Thus, we suggest Vivianite can be the nucleus for alternative phosphate recovery options. Excess and digested sewage sludge was sampled from full-scale MWTPs and analysed using x-ray diffraction (XRD), conventional scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), environmental SEM-EDX (eSEM-EDX) and Mossbauer spectroscopy. Vivianite was observed in all plants where iron was used for phosphate removal. In excess sludge before the anaerobic digestion, ferrous iron dominated the iron pool (≥50%) as shown by Mossbauer spectroscopy. XRD and Mossbauer spectroscopy showed no clear correlation between Vivianite bound phosphate versus the iron content in excess sludge. In digested sludge, ferrous iron was the dominant iron form (>85%). Phosphate bound in Vivianite increased with the iron content of the digested sludge but levelled off at high iron levels. 70-90% of all phosphate was bound in Vivianite in the sludge with the highest iron content (molar Fe:P = 2.5). The quantification of Vivianite was difficult and bears some uncertainty probably because of the presence of impure Vivianite as indicated by SEM-EDX. eSEM-EDX indicates that the Vivianite occurs as relatively small (20-100 μm) but free particles. We envisage very efficient phosphate recovery technologies that separate these particles based on their magnetic properties from the complex sludge matrix.
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Vivianite as an important iron phosphate precipitate in sewage treatment plants.
Water research, 2016Co-Authors: Philipp Wilfert, A I Dugulan, K Goubitz, Leon Korving, A. Mandalidis, Hardy Temmink, Geert-jan Witkamp, M C M Van LoosdrechtAbstract:Iron is an important element for modern sewage treatment, inter alia to remove phosphorus from sewage. However, phosphorus recovery from iron phosphorus containing sewage sludge, without incineration, is not yet economical. We believe, increasing the knowledge about iron-phosphorus speciation in sewage sludge can help to identify new routes for phosphorus recovery. Surplus and digested sludge of two sewage treatment plants was investigated. The plants relied either solely on iron based phosphorus removal or on biological phosphorus removal supported by iron dosing. Mossbauer spectroscopy showed that Vivianite and pyrite were the dominating iron compounds in the surplus and anaerobically digested sludge solids in both plants. Mossbauer spectroscopy and XRD suggested that Vivianite bound phosphorus made up between 10 and 30% (in the plant relying mainly on biological removal) and between 40 and 50% of total phosphorus (in the plant that relies on iron based phosphorus removal). Furthermore, Mossbauer spectroscopy indicated that none of the samples contained a significant amount of Fe(III), even though aerated treatment stages existed and although besides Fe(II) also Fe(III) was dosed. We hypothesize that chemical/microbial Fe(III) reduction in the treatment lines is relatively quick and triggers Vivianite formation. Once formed, Vivianite may endure oxygenated treatment zones due to slow oxidation kinetics and due to oxygen diffusion limitations into sludge flocs. These results indicate that Vivianite is the major iron phosphorus compound in sewage treatment plants with moderate iron dosing. We hypothesize that Vivianite is dominating in most plants where iron is dosed for phosphorus removal which could offer new routes for phosphorus recovery.
