Storage of human urine: acidification as a method to inhibit decomposition of urea

Hellström, Daniel; Johansson, Erica; Grennberg, Kerstin

doi:10.1016/s0925-8574(98)00074-3

Cited by 91 publications

(63 citation statements)

References 2 publications

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“…After a period of time, urease active bacteria, which are assumed ubiquitous in wastewater collection systems, hydrolyze urea to form ammonia and bicarbonate and increase the pH from 6 to 9 (Udert et al, 2003). Prevention of urea hydrolysis is an active area of research, and would require the addition of urease inhibitors to the urine collection system to prevent pipe blockages in plumbing due to precipitation (Hellstr€ om et al, 1999;Krajewska, 2009). Therefore, it is considered more practical to implement urine treatment technologies that effectively separate pharmaceuticals from nutrients in ureolyzed urine without the added step of preventing urea hydrolysis.…”

Section: Introductionmentioning

confidence: 99%

Ion-exchange selectivity of diclofenac, ibuprofen, ketoprofen, and naproxen in ureolyzed human urine

et al. 2015

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Section: Introductionmentioning

confidence: 99%

Ion-exchange selectivity of diclofenac, ibuprofen, ketoprofen, and naproxen in ureolyzed human urine

et al. 2015

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“…This specific value of pH was used based on the effect on the reaction rate described by Ito et al [4]. It was also based on the large capacity of acidic condition to avoid urea hydrolysis in the urine during storage and experiments [14,15]. The reaction temperature was kept at 25°C in a water bath.…”

Section: Methodsmentioning

confidence: 99%

Effect of Formaldehyde/Urea Ratio on Production Rate of Methylene Urea from Human Urine

Kabore

Ito

Funamizu

2016

J. of Wat. & Envir. Tech.

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Reclamation of nutrients from human urine for agricultural purposes is an alternative for chemical fertilizers. By reacting with formaldehyde, urea in human urine precipitates as slow-release fertilizer. However, the recovery of nitrogen decreases as formaldehyde is added and all of the nitrogen cannot be recovered. The aim of this paper was to find out the reason of this decrease. We assumed that some by-products of nitrogen might be created during the reaction and then limiting the polymerization process. Three levels of formaldehyde/urea (F/U) ratio have been investigated and the presence of undefined nitrogen compounds was found. These compounds were assumed to be low molecular weight polymers and by-products of nitrogen. Elution time of liquid chromatography with organic carbon detector (LC-OCD) corresponded to compounds of 350 Da and the degree of polymerization of the low molecular weight polymers was lower than 5. Mass spectrometry (MS) allows clear identification of by-products. They were essentially constituted by molecules with incomplete sequences of polymers. The reaction model proposes possible pathways that could lead to these by-products.

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“…In tests, the addition of sulphuric or acetic acid could inhibit urea decomposition for over 100 days. 65 Studies into the separation and stabilization of urine come mainly from the perspective of wastewater treatment. Most of this is driven by environmental concerns with the focus on sustainability, reducing waste, and mitigating nitrate build up in watercourses.…”

Section: Urea From Urinementioning

confidence: 99%

Urea as a hydrogen carrier: a perspective on its potential for safe, sustainable and long-term energy supply

Rollinson

Jones

Dupont

et al. 2011

Energy Environ. Sci.

246

169

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Recently, there have been publications reporting the use of urea, as a source of hydrogen/fuel cell power. There have however been no reports that singularly assess the suitability of urea for this purpose. This article provides not only a perspective on the attributes of urea ((NH 2 ) 2 CO) as a hydrogen carrier for fuel cells but also presents the findings of a review on the feasibility of utilising the enormous natural resource of urea that exists. Urea is a cheap and widely available commodity with well developed manufacturing infrastructure and a rapidly increasing volume of production. This offers rapid implementation of urea for application as a hydrogen carrie r either directly or as a source of ammonia. Compared with other industrial chemicals previously considered, urea has the advantages of being non-toxic, stable, and therefore easy to transport and store. This report reveals that the natural resource of urea could be a solution to long-term future sustainable hydrogen supply and that the present status of scientific knowledge necessary to extract this natural resource is in the most part understood. It is considered realistic that these sustainable routes could be exploited if they are given sufficient focus of research attention.

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Storage of human urine: acidification as a method to inhibit decomposition of urea

Cited by 91 publications

References 2 publications

Ion-exchange selectivity of diclofenac, ibuprofen, ketoprofen, and naproxen in ureolyzed human urine

Ion-exchange selectivity of diclofenac, ibuprofen, ketoprofen, and naproxen in ureolyzed human urine

Effect of Formaldehyde/Urea Ratio on Production Rate of Methylene Urea from Human Urine

Urea as a hydrogen carrier: a perspective on its potential for safe, sustainable and long-term energy supply

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