Struvite Phosphorus Recovery from Aerobically Digested Municipal Wastewater
1
Talquin Electric Cooperative Inc., Quincy, FL 32351, USA
2
North Florida Research and Education Center, University of Florida-IFAS, Quincy, FL 32351 USA
3
Soil and Water Sciences Department, University of Florida-IFAS, Gainesville, FL 32611 USA
*
Author to whom correspondence should be addressed.
Sustainability 2019, 11(2), 376; https://doi.org/10.3390/su11020376
Received: 21 November 2018 / Revised: 29 December 2018 / Accepted: 30 December 2018 / Published: 13 January 2019
(This article belongs to the Section Environmental Sustainability and Applications)
Small, municipal wastewater treatment plants (WWTPs) that use aerobic digestion treat approximately 40% of the discharged wastewater in the USA, and yet they are an overlooked source of recoverable P. There are no known reports of small, aerobic WWTPs recovering P through struvite (MgNH4PO4·6H2O) precipitation for repurposing as a mineral fertilizer, even though some large WWTPs with anaerobic digestion are. Four small WWTPs in north Florida, USA, with treatment capacities from 371 to 2650 m3 wastewater d−1 and incoming P loads from 2 to 14 kg d−1 were investigated for their potential to produce struvite from digester filtrates. A chemical equilibrium model was used to predict the feasibility of struvite production and the results compared with actual WWTP filtrate measurements. Filtrates from aerobic digesters were able to form struvite if solution pH was increased by ≤1 pH unit. Depending on the WWTP, P recovery in filtrates through struvite precipitation ranged from 27–57% by mass at pH 8.5, via NaOH additions or air sparging. Increasing filtrate Mg concentrations improved P recovery up to 97%. Based upon these results, small WWTPs using aerobic digestion will be able to lower their P waste output through recovery as struvite fertilizer.
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MDPI and ACS Style
Hallas, J.F.; Mackowiak, C.L.; Wilkie, A.C.; Harris, W.G. Struvite Phosphorus Recovery from Aerobically Digested Municipal Wastewater. Sustainability 2019, 11, 376. https://doi.org/10.3390/su11020376
AMA Style
Hallas JF, Mackowiak CL, Wilkie AC, Harris WG. Struvite Phosphorus Recovery from Aerobically Digested Municipal Wastewater. Sustainability. 2019; 11(2):376. https://doi.org/10.3390/su11020376
Chicago/Turabian StyleHallas, John F., Cheryl L. Mackowiak, Ann C. Wilkie, and Willie G. Harris 2019. "Struvite Phosphorus Recovery from Aerobically Digested Municipal Wastewater" Sustainability 11, no. 2: 376. https://doi.org/10.3390/su11020376
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