Fate of nitrogen during volume reduction of human urine using an on-site volume reduction system.
Environ Technol
; 33(1-3): 229-35, 2012.
Article
em En
| MEDLINE
| ID: mdl-22519107
ABSTRACT
This study was carried to assess the effect of a mixture of salts, urea and creatinine on water evaporation from urine using an on-site volume reduction system in long-term experiments. Subsequently, the fate of nitrogen during volume reduction of urine was also assessed. The water evaporation rate, salt accumulation in the gauze sheet, concentrations of urea and ammonia-N, and pH of urine were measured periodically. Based on the results, a mass balance of nitrogen in concentrated urine was calculated for a moderate evaporating condition. The results revealed that steady-state evaporation was observed throughout the experiment period without any inhibition due to salt accumulation. Salt concentration in the gauze sheet reached steady-state illustrating the possibility of salt falling back to the tank from the sheet. No significant reduction of urea was observed for a moderate evaporating condition, which indicates inhibition of urea hydrolysis by the high concentration of the mixture of salts, urea and creatinine in the urine. In contrast, for a low evaporating condition, the pH of the urine increased to 8.9, which indicates early urea hydrolysis, causing an offensive odour and ammonia loss to the air. In simple storage experiments, a mixture of salts, urea and creatinine amounting to 227-334 g L(-1) in urine inhibited urea hydrolysis, even with faecal contamination, at 25 degrees C, while urine samples containing a mixture of salts, urea and creatinine at less than 227 g L(-1) did not provide strong inhibition of hydrolysis.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ureia
/
Urina
/
Eliminação de Resíduos Líquidos
/
Amônia
/
Nitrogênio
Tipo de estudo:
Evaluation_studies
Limite:
Humans
Idioma:
En
Revista:
Environ Technol
Assunto da revista:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Japão