Effect of the stirring speed on the struvite formation using the centrate from a WWTP





Waste water, Phosphorus recovery, Struvite crystallization, Velocity gradient (g), Sustainable development


The formation of struvite (MgNH4PO4·6H2O) for nutrient recovery in wastewater treatment plants has been widely investigated; however, little attention has been paid to the effect of stirring speeds on the resulting particle size, which could affect its agronomic value as a slow-release fertilizer. In this study, struvite formation from the centrate of sewage digestate was performed under six stirring speeds (0, 100, 200, 300, 400, 500 rpm). The resulting struvite crystals were characterised using X-ray diffraction and scanning electron microscopy with energy dispersive X-ray spectroscopy. The average particle size of struvite crystals increased from 55 µm at 0 rpm to 127 µm at 100 rpm and 128 µm at 200 rpm. Further increments in stirring speeds resulted in smaller crystal sizes. These results indicated that the largest particle size can be obtained at stirring speeds ranging from 100 to 200 rpm, equivalent to a velocity gradient between 79 and 188 s-1, as there was no statistically significant difference between mean values (t-test, p<0.05). The optimum stirring speed range reported herein can be used to set operational conditions for struvite crystallisation with the benefit of producing large crystals and reducing energy consumption in stirring tanks.

= 178 veces | PDF
= 150 veces|


Download data is not yet available.

Author Biographies

Carolina González Morales, University of Antioquia

GAIA Group, Environmental School, Faculty of Engineering.

Miller Alonso Camargo-Valero, National University of Colombia

Associate Professor, Department of Chemical Engineering.

Francisco José Molina Pérez, University of Antioquia

Associate Professor, GAIA Group, Environmental School, Faculty of Engineering.


Belén Fernández, Institute of Agri-Food Science and Technology

IRTA - GIRO Program.


A. Guadiea and et al., “Enhanced struvite recovery from wastewater using a novel cone-inserted fluidized bed reactor,” J. Environ. Sci., vol. 26, no. 4, April 1 2014. [Online]. Available: https://doi.org/10.1016/S1001-0742(13)60469-6

Z. Ye and et al., “Phosphorus recovery from wastewater by struvite crystallization: Property of aggregates,” J. Environ. Sci., vol. 26, no. 5, May 2014. [Online]. Available: https://doi.org/10.1016/S1001-0742(13)60536-7

J. D. Doyle and S. A. Parsons, “Struvite formation, control and recovery,”Water Res., vol. 36, no. 16, September 2002. [Online]. Available: https://doi.org/10.1016/S0043-1354(02)00126-4

N. Morales, M. A. Boehler, S. Buettner, C. Liebi, and H. Siegrist, “Recovery of n and p from urine by struvite precipitation followed by combined stripping with digester sludge liquid at full scale,” water, vol. 5, no. 3, August 29 2013. [Online]. Available: https://doi.org/10.3390/w5031262

K. P. Fattah, “Assessing struvite formation potential at wastewater treatment plants,” IJESD, vol. 3, no. 6, 2012. [Online]. Available: https://doi.org/10.7763/IJESD.2012.V3.284

A. Uysal, Y. D. Yilmazel, and G. N. Demirer, “The determination of fertilizer quality of the formed struvite from effluent of a sewage sludge anaerobic digester,” J. Hazard. Mater., vol. 181, no. 1-3, September 2010. [Online]. Available: https://doi.org/10.1016/j.jhazmat.2010.05.004

R. W. Holloway, A. E. Childress, K. E. Dennett, and T. Y. Cath, “Forward osmosis for concentration of anaerobic digester centrate,” Water Research, vol. 41, no. 17, September 2007. [Online]. Available: https://doi.org/10.1016/j.watres.2007.05.054

E. M. Jordaan, “Development of an aerated struvite crystallization reactor for phosphorus removal and recovery from swine manure,” M.S. thesis, University of Manitoba, Winnipeg, Canadá, 2011.

P. Battistoni, A. D. Angelis, M. Prisciandaro, R. Boccadoro, and D. Bolzonella, “P removal from anaerobic supernatants by struvite crystallization: long term validation and process modellingr,” Water Research, vol. 36, no. 8, April 2002. [Online]. Available: https://doi.org/10.1016/S0043-1354(01)00401-8

A. Muhmood, J. Lu, R. Dong, and S. Wu, “Formation of struvite from agricultural wastewaters and its reuse on farmlands: Status and hindrances to closing the nutrient loop,” J. Environ. Manage., vol. 230, January 15 2019. [Online]. Available: https://doi.org/10.1016/j.jenvman.2018.09.030

B. Li and et al., “Phosphorous recovery through struvite crystallization: Challenges for future design,” Sci. Total Environ., vol. 648, January 15 2019. [Online]. Available: https://doi.org/10.1016/j.scitotenv.2018.07.166

K. S. L. Corre, E. Valsami, P. Hobbs, and S. A. Parsons, “Phosphorus recovery from wastewater by struvite crystallization: A review,” Environ. Sci. Technol., vol. 39, no. 6, May 28 2009. [Online]. Available: https://doi.org/10.1080/10643380701640573

M. M. Rahman and et al., “Production of slow release crystal fertilizer from wastewaters through struvite crystallization – a review,” Arab. J. Chem., vol. 7, no. 1, January 2014. [Online]. Available: https://doi.org/10.1016/j.arabjc.2013.10.007

X. Ye and et al., “A comprehensive understanding of saturation index and upflow velocity in a pilot-scale fluidized bed reactor for struvite recovery from swine wastewater,” Powder Technol., vol. 295, July 2016. [Online]. Available: https://doi.org/10.1016/j.powtec.2016.03.022

P. Battistoni, R. Boccadoro, F. Fatone, and P. Pavan, “Auto-nucleation and crystal growth of struvite in a demonstrative fluidized bed reactor (fbr),” Environ. Technol., vol. 26, no. 9, May 11 2005. [Online]. Available: https://doi.org/10.1080/09593332608618486

K. S. Le Corre and E. Valsami and P. Hobbs and B. Jefferson and S. A. Parsons, “Struvite crystallisation and recovery using a stainless steel structure as a seed material,” Water Research, vol. 41, no. 11, June 2007. [Online]. Available: https://doi.org/10.1016/j.watres.2007.03.002

J. Wang, X. Ye, Z. Zhang, Y. Zhi, and S. Chen, “Selection of cost-effective magnesium sources for fluidized struvite crystallization,” J. Environ. Sci., vol. 70, August 2018. [Online]. Available: https://doi.org/10.1016/j.jes.2017.11.029

E. Tarragó, S. Puig, M. Ruscalleda, M. D. Balaguer, and J. Colprim, “Controlling struvite particles’ size using the up-flow velocity,” Chem. Eng. J., vol. 302, October 15 2016. [Online]. Available: https://doi.org/10.1016/j.cej.2016.06.036

L. Pastor. (2006) Investigations on the recovery of phosphorus from wastewater by crystallization. [Dissertation.com]. [Online]. Available: http://www.dissertation.com/m/books/1581123337

M. Ronteltap, M. Maurer, R. Hausherr, and W. Gujer, “Struvite precipitation from urine – influencing factors on particle size,” Water Res., vol. 44, no. 6, March 2010. [Online]. Available: https://doi.org/10.1016/j.watres.2009.12.015

S. Dhakal, “A laboratory study of struvite precipitation for phosphorus removal from concentrated animal feeding operation wastewater,” M.S. thesis, Missouri University of Science and Technology, Rolla, [USA], 2008.

D. Crutchik, N. Morales, J. M. Garrido, and J. R. Vázquez, “Enhancement of struvite pellets crystallization in a full- scale plant using an industrial grade magnesium product,” Water. Sci. Technol., vol. 75, no. 3, February 13 2017. [Online]. Available: https://doi.org/10.2166/wst.2016.527

X. Liu and et al., “Influence of process parameters on phosphorus recovery by struvite formation from urine,” Water Sci. Technol., vol. 68, no. 11, pp. 2434–2440, 2013.

M. Cerrillo, J. Palatsi, J. Comas, J. Vicens, and A.Bonmatí, “Struvite precipitation as a technology to be integrated in a manure anaerobic digestion treatment plant – removal efficiency, crystal characterization and agricultural assessment,” J. Chem. Technol. Biotechnol., vol. 90, no. 6, June 13 2015. [Online]. Available: https://doi.org/10.1002/jctb.4459

D. Kim, J. Kim, R. Hong, and L. Sang, “Effect of mixing on spontaneous struvite precipitation from semiconductor wastewater,” Bioresour. Technol., vol. 100, no. 1, January 2009. [Online]. Available: https://doi.org/10.1016/j.biortech.2008.05.024

American Public Health Association and American Water Works Association and Water Environment Federation, Standard methods for the examination of water and wastewater, 20th ed. Washington, D.C: APHA-AWWA-WEF, 1998.

The International Centre for Diffraction Data (ICDD). PDF-2. Accessed May. 28, 2019. [Online]. Available: http://www.icdd.com/index.php/pdf-2/

Image J, National institutes of Health, 2016.

S. Rodrigues, “Precipitação de estruvita: recuperação de nitrogênio e fósforo utilizando fontes alternativas de reagentes,” Ph.D. dissertation, Universidade Federal de Minas Gerais, Belo horizonte, Brazil, 2014.

A. Capdevielle, E. Sýkorová, B. Biscans, F. Béline, and M. L. Daumer, “Optimization of struvite precipitation in synthetic biologically treated swine wastewater-determination of the optimal process 49 C. González-Morales et al., Revista Facultad de Ingeniería, Universidad de Antioquia, No. 92, pp. 42-50, 2019 parameters,” J. Hazard. Mater., vol. 244–245, January 15 2013. [Online]. Available: https://doi.org/10.1016/j.jhazmat.2012.11.054

N. Y. Acelas, E. Flórez, and D. López, “Phosphorus recovery through struvite precipitation from wastewater: effect of the competitive ions,” Desalin. Water Treat, vol. 54, no. 9, March 27 2014. [Online]. Available: https://doi.org/10.1080/19443994.2014.902337

X. D. Hao, C. C. Wang, L. Lan, and M. C. M. V. Loosdrecht, “Struvite formation, analytical methods and effects of ph and ca2+,” Water Sci. Technol., vol. 58, no. 8, 2008. [Online]. Available: https://doi.org/10.2166/wst.2008.557

L. Pastor, “Estudio de la precipitación y recuperación del fósforo presente en las aguas residuales en forma de estruvita (mgnh4po4·6h2o),” Ph.D. dissertation, Departamento de Ingeniería Hidráulica y Medio Ambiente, Universidad Politécnica de Valencia, Valencia, España, 2008.

D. A. Cornwell and M. M. Bishop, “Determining velocity gradients in laboratory and fullscale systems,” Journal (American Water Works Association), vol. 75, no. 9, September 01 1983. [Online]. Available: https://doi.org/10.1002/j.1551-8833.1983.tb05197.x

M. I. H. Bhuiyan, D. S. Mavinic, and F. A. Koch, “Phosphorus recovery from wastewater through struvite formation in fluidized bed reactors: a sustainable approach.” Water Sci. Technol., vol. 57, no. 2, 2008. [Online]. Available: https://doi.org/10.2166/wst.2008.002.

D. Crutchik, S. Rodrigues, D. Ruddle, and J. M. Garrido, “Evaluation of a low-cost magnesium product for phosphorus recovery by struvite crystallization,” J. Chem. Technol. Biotechnol., vol. 93, no. 4, April 2018. [Online]. Available: https://doi.org/10.1002/jctb.5453

Y. Jaffer, T. A. Clark, P. Pearce, and S. A. Parsons, “Potential phosphorus recovery by struvite formation,” Water Research, vol. 36, no. 7, April 2002. [Online]. Available: https://doi.org/10.1016/S0043-1354(01)00391-8

E. Ariyanto, H. M. Ang, and T. K. Sen, “The influence of various process parameters on dissolution kinetics and mechanism of struvite seed crystals,” Journal of the Institution of Engineers (India): Series A, vol. 98, no. 3, September 2017. [Online]. Available: https://doi.org/10.1007/s40030-017-0212-4




How to Cite

González Morales, C., Camargo-Valero, M. A., Molina Pérez, F. J., & Fernández, B. (2019). Effect of the stirring speed on the struvite formation using the centrate from a WWTP. Revista Facultad De Ingeniería Universidad De Antioquia, (92), 42–50. https://doi.org/10.17533/10.17533/udea.redin.20190518