Urea hydrolysis and precipitation dynamics in a urine-collecting system

Udert, Kai M.; Larsen, Tove A.; Biebow, Martin; Gujer, Willi

doi:10.1016/s0043-1354(03)00065-4

Cited by 386 publications

(304 citation statements)

References 16 publications

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“…However, for practical purposes, the simpler and more economical approach seems to be the use of magnesium oxide in powder form, as no extra chemicals are required and obtained results were equivalents after a reaction time of 30 min. pH of fresh urine samples collected in the inflow of the urine storage tank was around 7.2, the same value observed by Udert et al [29], but that value rose in the storage tank to values around 9.1-9.3 due to the ureolysis (Udert et al [29] obtained a pH of 9.0 in stored urine). The precipitation experiments showed that the pH rose by 0.04 units after MgO addition in powder and dropped 0.04 units if MgO was pre-solved in acid, in consequence, no significant pH variations were produced by the reagent addition.…”

Section: Magnesium Dose and Reaction Time Determination Urine Pre-trsupporting

confidence: 78%

“…Literature values for phosphorus concentration in fresh human urine samples are about 740 mg P/L [28]. However, in the storage tank, that value can be reduced to 76 mg P/L due to the ureolysis (urea is hydrolyzed to ammonia by naturally-occurring bacteria) and subsequent struvite precipitation [29], while total phosphate precipitation is limited by the lack of magnesium.…”

Section: Magnesium Dose and Reaction Time Determination Urine Pre-trmentioning

confidence: 99%

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

Morales

Boehler

Buettner³

et al. 2013

Water

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A novel ammonia stripping method, including a CO 2 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. OPEN ACCESSWater 2013, 5 1263

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Section: Magnesium Dose and Reaction Time Determination Urine Pre-trsupporting

confidence: 78%

Section: Magnesium Dose and Reaction Time Determination Urine Pre-trmentioning

confidence: 99%

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

Morales

Boehler

Buettner³

et al. 2013

Water

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“…In Kenya, up to 720 Ascaris eggs per litre were found in the urine of poorly maintained UDTs in a school (Kraft, 2010). The harsh chemical conditions of stored urine, in particular the high pH and ammonia concentration caused by urea hydrolysis (Udert et al, 2003), promote the inactivation of microorganisms. These conditions lead to high levels of free ammonia (NH 3 ), a constituent known to be biocidal for most organisms (Cramer et al, 1983;Jenkins et al, 1998;Pecson and Nelson, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Struvite production mainly aims at recovering phosphorus from urine, since only a small percentage of the ammonia in the initial urine solution is recovered (Etter et al, 2011). Some struvite spontaneously precipitates during urine storage due to urea hydrolysis (Udert et al, 2003), though more significant quantities can be generated by adding magnesium-containing minerals. Struvite crystallization is a fast process, taking only a few minutes (Etter et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Fate of the pathogen indicators phage ΦX174 and Ascaris suum eggs during the production of struvite fertilizer from source-separated urine

et al. 2011

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“…Diurnal variations can also be observed. (UDERT et al, 2003a(UDERT et al, , 2003b. Urine is the main source of ammonia in domestic wastewater as urea is easily hydrolyzed according to the following reaction (UDERT et al, 2003b):…”

Section: Resultsmentioning

confidence: 99%

Relation Between Conductivity and Ion Content in Urban Wastewater

Bonté

Pons

Potier

et al. 2008

rseau

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Wastewater conductivity has been monitored for extended periods of time by in situ probes and on grabbed samples in four communities (from 1,000 to 350,000 PE). In parallel, the concentrations of the main ionic contributors, such as calcium, sodium, potassium, magnesium, ammonium, ortho-phosphate, chloride and sulphate have been measured and their variations with respect to time compared to human activity patterns. It appears that sodium, potassium, ammonium and ortho-phosphate, which contribute to about 34% to wastewater conductivity, exhibit diurnal variations in phase with human activity evaluated by absorbance at 254 nm. However calcium (≈ 22% of wastewater conductivity) is out‑of-phase. This release, ahead of the one of other cations and anions, could be related to sewer concrete corrosion or to groundwater infiltration. The combination of these different ionic contributions creates a conductivity pattern which cannot be easily related to human activity. It makes difficult to integrate conductivity in a monitoring system able to detect ion-related abnormalities in wastewater quality.Les variations de la conductivité d’eaux usées urbaines ont été suivies sur de longues durées a l’aide de sondes placées in situ en entrée d’installations de traitement et sur des échantillons prélevés automatiquement. Quatre communautés (entre 1 000 et 350 000 habitants) ont été choisies pour cette étude. On a également dosé sur les échantillons les principaux ions (calcium, sodium, potassium, magnésium, ammonium, ortho-phosphates, chlorures et sulfates). Il apparait que le sodium, le potassium, l’ammonium et les ortho-phosphates contribuent pour 34 % a la conductivité des eaux usées et présentent des variations journalicres en phase avec la pollution carbonée soluble, estimée a partir de l’absorbance a 254 nm. Par contre, le calcium, qui contribue pour 22 % a la conductivité, présente un déphasage qui peut ztre du a son transport dans le réseau d’assainissement du fait de la corrosion des conduites en béton ou a des infiltrations d’eaux claires. Finalement, la combinaison de ces différentes contributions ioniques conduit a une variabilité de la conductivité qu’il n’est pas facile de lier a l’activité humaine, et donc a des rejets accidentels dans le cadre d’un systcme de détection de variation anormale de la qualité des eaux usées

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Urea hydrolysis and precipitation dynamics in a urine-collecting system

Cited by 386 publications

References 16 publications

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

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

Fate of the pathogen indicators phage ΦX174 and Ascaris suum eggs during the production of struvite fertilizer from source-separated urine

Relation Between Conductivity and Ion Content in Urban Wastewater

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