Water 2013, 5(3), 1262-1278; doi:10.3390/w5031262
Article

Recovery of N and P from Urine by Struvite Precipitation Followed by Combined Stripping with Digester Sludge Liquid at Full Scale

1 Eawag, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf 8600, Switzerland 2 Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, Santiago de Compostela, Galicia 15782, Spain 3 Ingenieurbüro Gujer AG, Ruemlang CH 8153, Switzerland 4 WWTP Abwasserreinigung Kloten-Opfikon, Opfikon CH-8152, Switzerland
* Author to whom correspondence should be addressed.
Received: 12 June 2013; in revised form: 8 July 2013 / Accepted: 12 August 2013 / Published: 29 August 2013
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Abstract: A novel ammonia stripping method, including a CO2 pre-stripper was used to treat a mix of supernatant liquor from an anaerobic digester and urine in order to recycle nitrogen as ammonium sulfate at full-scale in the WWTP Kloten/Opfikon. Waste streams were not generated, since the ammonia was recovered as a marketable nitrogen fertilizer, turning a waste product into a valuable product. The efficiency of this system was increased by means of the addition of pre-treated urine collected separately at EAWAG building. The separation step was performed by the use of water free urinals and urine diversion flush toilets. An increase of 10% in the liquid flux with the addition of the urine translated into a 40% increase of the ammonia concentration in the inlet of the stripping unit. The achievement of these percentages generated a proportional increase in the fertilizer production. The urine pre-treatment was carried out by adding magnesium to produce a precipitate of struvite. The first experiments with the combined treatment showed the feasibility of the combination of the separation and pre-treatment steps.
Keywords: air stripping; ammonium sulfate; nutrients recovery; urine treatment; struvite

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MDPI and ACS Style

Morales, N.; Boehler, M.A.; Buettner, S.; Liebi, C.; Siegrist, H. Recovery of N and P from Urine by Struvite Precipitation Followed by Combined Stripping with Digester Sludge Liquid at Full Scale. Water 2013, 5, 1262-1278.

AMA Style

Morales N, Boehler MA, Buettner S, Liebi C, Siegrist H. Recovery of N and P from Urine by Struvite Precipitation Followed by Combined Stripping with Digester Sludge Liquid at Full Scale. Water. 2013; 5(3):1262-1278.

Chicago/Turabian Style

Morales, Nicolás; Boehler, Marc A.; Buettner, Sandra; Liebi, Christoph; Siegrist, Hansruedi. 2013. "Recovery of N and P from Urine by Struvite Precipitation Followed by Combined Stripping with Digester Sludge Liquid at Full Scale." Water 5, no. 3: 1262-1278.

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