Sulfide induced phosphate release from iron phosphates and its potential for phosphate recovery

P. Wilfert, J. Meerdink, B. Degaga, H. Temmink, L. Korving, G.J. Witkamp, K. Goubitz, M.C.M. van Loosdrecht*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Sulfide is frequently suggested as a tool to release and recover phosphate from iron phosphate rich waste streams, such as sewage sludge, although systematic studies on mechanisms and efficiencies are missing. Batch experiments were conducted with different synthetic iron phosphates (purchased Fe(III)P, Fe(III)P synthesized in the lab and vivianite, Fe(II)3(PO4)2*8H2O), various sewage sludges (with different molar Fe:P ratios) and sewage sludge ash. When sulfide was added to synthetic iron phosphates (molar Fe:S = 1), phosphate release was completed within 1 h with a maximum release of 92% (vivianite), 60% (purchased Fe(III)P) and 76% (synthesized Fe(III)P). In the latter experiment, rebinding of phosphate to Fe(II) decreased net phosphate release to 56%. Prior to the re-precipitation, phosphate release was very efficient (P released/S input) because it was driven by Fe(III) reduction and not by, more sulfide demanding, FeSx formation. This was confirmed in low dose sulfide experiments without significant FeSx formation. Phosphate release from vivianite was very efficient because sulfide reacts directly (1:1) with Fe(II) to form FeSx, without Fe(III) reduction. At the same time vivianite-Fe(II) is as efficient as Fe(III) in binding phosphate. From digested sewage sludge, sulfide dissolved maximally 30% of all phosphate, from the sludge with the highest iron content which was not as high as suggested in earlier studies. Sludge dewaterability (capillary suction test, 0.13 ± 0.015 g2(s2m4)−1) dropped significantly after sulfide addition (0.06 ± 0.004 g2(s2m4)−1). Insignificant net phosphate release (1.5%) was observed from sewage sludge ash. Overall, sulfide can be a useful tool to release and recover phosphate bound to iron from sewage sludge. Drawbacks -deterioration of the dewaterability and a net phosphate release that is lower than expected-need to be investigated.

Original languageEnglish
Article number115389
JournalWater Research
Volume171
DOIs
Publication statusPublished - 15 Mar 2020

Fingerprint

Phosphates
sulfide
phosphate
Iron
Recovery
iron
Sewage sludge
vivianite
Ashes
Sulfides
ash
sludge
experiment
Experiments
suction
Deterioration
sewage sludge

Keywords

  • Iron
  • Phosphate recovery
  • Sewage sludge
  • Sulfide

Cite this

Wilfert, P., Meerdink, J., Degaga, B., Temmink, H., Korving, L., Witkamp, G. J., ... van Loosdrecht, M. C. M. (2020). Sulfide induced phosphate release from iron phosphates and its potential for phosphate recovery. Water Research, 171, [115389]. https://doi.org/10.1016/j.watres.2019.115389
Wilfert, P. ; Meerdink, J. ; Degaga, B. ; Temmink, H. ; Korving, L. ; Witkamp, G.J. ; Goubitz, K. ; van Loosdrecht, M.C.M. / Sulfide induced phosphate release from iron phosphates and its potential for phosphate recovery. In: Water Research. 2020 ; Vol. 171.
@article{f89c6aeeae5c479da8d05928a4988284,
title = "Sulfide induced phosphate release from iron phosphates and its potential for phosphate recovery",
abstract = "Sulfide is frequently suggested as a tool to release and recover phosphate from iron phosphate rich waste streams, such as sewage sludge, although systematic studies on mechanisms and efficiencies are missing. Batch experiments were conducted with different synthetic iron phosphates (purchased Fe(III)P, Fe(III)P synthesized in the lab and vivianite, Fe(II)3(PO4)2*8H2O), various sewage sludges (with different molar Fe:P ratios) and sewage sludge ash. When sulfide was added to synthetic iron phosphates (molar Fe:S = 1), phosphate release was completed within 1 h with a maximum release of 92{\%} (vivianite), 60{\%} (purchased Fe(III)P) and 76{\%} (synthesized Fe(III)P). In the latter experiment, rebinding of phosphate to Fe(II) decreased net phosphate release to 56{\%}. Prior to the re-precipitation, phosphate release was very efficient (P released/S input) because it was driven by Fe(III) reduction and not by, more sulfide demanding, FeSx formation. This was confirmed in low dose sulfide experiments without significant FeSx formation. Phosphate release from vivianite was very efficient because sulfide reacts directly (1:1) with Fe(II) to form FeSx, without Fe(III) reduction. At the same time vivianite-Fe(II) is as efficient as Fe(III) in binding phosphate. From digested sewage sludge, sulfide dissolved maximally 30{\%} of all phosphate, from the sludge with the highest iron content which was not as high as suggested in earlier studies. Sludge dewaterability (capillary suction test, 0.13 ± 0.015 g2(s2m4)−1) dropped significantly after sulfide addition (0.06 ± 0.004 g2(s2m4)−1). Insignificant net phosphate release (1.5{\%}) was observed from sewage sludge ash. Overall, sulfide can be a useful tool to release and recover phosphate bound to iron from sewage sludge. Drawbacks -deterioration of the dewaterability and a net phosphate release that is lower than expected-need to be investigated.",
keywords = "Iron, Phosphate recovery, Sewage sludge, Sulfide",
author = "P. Wilfert and J. Meerdink and B. Degaga and H. Temmink and L. Korving and G.J. Witkamp and K. Goubitz and {van Loosdrecht}, M.C.M.",
year = "2020",
month = "3",
day = "15",
doi = "10.1016/j.watres.2019.115389",
language = "English",
volume = "171",
journal = "Water Research",
issn = "0043-1354",
publisher = "IWA Publishing",

}

Wilfert, P, Meerdink, J, Degaga, B, Temmink, H, Korving, L, Witkamp, GJ, Goubitz, K & van Loosdrecht, MCM 2020, 'Sulfide induced phosphate release from iron phosphates and its potential for phosphate recovery', Water Research, vol. 171, 115389. https://doi.org/10.1016/j.watres.2019.115389

Sulfide induced phosphate release from iron phosphates and its potential for phosphate recovery. / Wilfert, P.; Meerdink, J.; Degaga, B.; Temmink, H.; Korving, L.; Witkamp, G.J.; Goubitz, K.; van Loosdrecht, M.C.M.

In: Water Research, Vol. 171, 115389, 15.03.2020.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Sulfide induced phosphate release from iron phosphates and its potential for phosphate recovery

AU - Wilfert, P.

AU - Meerdink, J.

AU - Degaga, B.

AU - Temmink, H.

AU - Korving, L.

AU - Witkamp, G.J.

AU - Goubitz, K.

AU - van Loosdrecht, M.C.M.

PY - 2020/3/15

Y1 - 2020/3/15

N2 - Sulfide is frequently suggested as a tool to release and recover phosphate from iron phosphate rich waste streams, such as sewage sludge, although systematic studies on mechanisms and efficiencies are missing. Batch experiments were conducted with different synthetic iron phosphates (purchased Fe(III)P, Fe(III)P synthesized in the lab and vivianite, Fe(II)3(PO4)2*8H2O), various sewage sludges (with different molar Fe:P ratios) and sewage sludge ash. When sulfide was added to synthetic iron phosphates (molar Fe:S = 1), phosphate release was completed within 1 h with a maximum release of 92% (vivianite), 60% (purchased Fe(III)P) and 76% (synthesized Fe(III)P). In the latter experiment, rebinding of phosphate to Fe(II) decreased net phosphate release to 56%. Prior to the re-precipitation, phosphate release was very efficient (P released/S input) because it was driven by Fe(III) reduction and not by, more sulfide demanding, FeSx formation. This was confirmed in low dose sulfide experiments without significant FeSx formation. Phosphate release from vivianite was very efficient because sulfide reacts directly (1:1) with Fe(II) to form FeSx, without Fe(III) reduction. At the same time vivianite-Fe(II) is as efficient as Fe(III) in binding phosphate. From digested sewage sludge, sulfide dissolved maximally 30% of all phosphate, from the sludge with the highest iron content which was not as high as suggested in earlier studies. Sludge dewaterability (capillary suction test, 0.13 ± 0.015 g2(s2m4)−1) dropped significantly after sulfide addition (0.06 ± 0.004 g2(s2m4)−1). Insignificant net phosphate release (1.5%) was observed from sewage sludge ash. Overall, sulfide can be a useful tool to release and recover phosphate bound to iron from sewage sludge. Drawbacks -deterioration of the dewaterability and a net phosphate release that is lower than expected-need to be investigated.

AB - Sulfide is frequently suggested as a tool to release and recover phosphate from iron phosphate rich waste streams, such as sewage sludge, although systematic studies on mechanisms and efficiencies are missing. Batch experiments were conducted with different synthetic iron phosphates (purchased Fe(III)P, Fe(III)P synthesized in the lab and vivianite, Fe(II)3(PO4)2*8H2O), various sewage sludges (with different molar Fe:P ratios) and sewage sludge ash. When sulfide was added to synthetic iron phosphates (molar Fe:S = 1), phosphate release was completed within 1 h with a maximum release of 92% (vivianite), 60% (purchased Fe(III)P) and 76% (synthesized Fe(III)P). In the latter experiment, rebinding of phosphate to Fe(II) decreased net phosphate release to 56%. Prior to the re-precipitation, phosphate release was very efficient (P released/S input) because it was driven by Fe(III) reduction and not by, more sulfide demanding, FeSx formation. This was confirmed in low dose sulfide experiments without significant FeSx formation. Phosphate release from vivianite was very efficient because sulfide reacts directly (1:1) with Fe(II) to form FeSx, without Fe(III) reduction. At the same time vivianite-Fe(II) is as efficient as Fe(III) in binding phosphate. From digested sewage sludge, sulfide dissolved maximally 30% of all phosphate, from the sludge with the highest iron content which was not as high as suggested in earlier studies. Sludge dewaterability (capillary suction test, 0.13 ± 0.015 g2(s2m4)−1) dropped significantly after sulfide addition (0.06 ± 0.004 g2(s2m4)−1). Insignificant net phosphate release (1.5%) was observed from sewage sludge ash. Overall, sulfide can be a useful tool to release and recover phosphate bound to iron from sewage sludge. Drawbacks -deterioration of the dewaterability and a net phosphate release that is lower than expected-need to be investigated.

KW - Iron

KW - Phosphate recovery

KW - Sewage sludge

KW - Sulfide

U2 - 10.1016/j.watres.2019.115389

DO - 10.1016/j.watres.2019.115389

M3 - Article

VL - 171

JO - Water Research

JF - Water Research

SN - 0043-1354

M1 - 115389

ER -