On-site urine treatment combining Ca(OH)2 dissolution and dehydration with ambient air

We present the results of three field tests and three laboratory tests of a new physical-chemical urine treatment system, which can recover all nutrients, while pathogens are inactivated. The system consists of two steps. In the first reactor, biological processes including urea hydrolysis are preve...

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Autores principales:	Michel E. Riechmann, Bonginkosi Ndwandwe, Esther E. Greenwood, Eva Reynaert, Eberhard Morgenroth, Kai M. Udert
Formato:	article
Lenguaje:	EN
Publicado:	Elsevier 2021
Materias:	Field testing Resource recovery Urine stabilization Calcium hydroxide Source separation Blue Diversion Autarky Environmental technology. Sanitary engineering TD1-1066
Acceso en línea:	https://doaj.org/article/df19303c85b048afb653a740a5d27996
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spelling	oai:doaj.org-article:df19303c85b048afb653a740a5d279962021-12-02T05:03:32ZOn-site urine treatment combining Ca(OH)2 dissolution and dehydration with ambient air2589-914710.1016/j.wroa.2021.100124https://doaj.org/article/df19303c85b048afb653a740a5d279962021-12-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S2589914721000372https://doaj.org/toc/2589-9147We present the results of three field tests and three laboratory tests of a new physical-chemical urine treatment system, which can recover all nutrients, while pathogens are inactivated. The system consists of two steps. In the first reactor, biological processes including urea hydrolysis are prevented by mixing fresh urine with calcium hydroxide (Ca(OH)2). Due to the high pH value and the high availability of calcium, phosphate can be recovered by precipitation. The high pH value also fosters the inactivation of microorganisms, including pathogens. In the second reactor, water is evaporated at low energy consumption by blowing unheated ambient air over the stabilized urine. Stabilization in the first reactor was successful in all field and laboratory tests. The pH value remained between 12 and 13, except for short dips due to shortages of Ca(OH)2. Nearly all phosphorus (92-96%) precipitated and could be recovered as calcium phosphate in the first reactor, while nitrogen and potassium overflowed with the urine into the evaporation reactor. The efficiency of the second treatment step was very different for field and laboratory experiments and depended on the duration of the experiment. During a four-day laboratory test, nitrogen recovery was 98%. In contrast, nitrogen recovery was only around 20% in the long-term field experiments. The high nitrogen losses occurred, because biological urea hydrolysis was not inhibited anymore, when the pH value in the second reactor decreased due to the dissolution of high amounts of carbon dioxide from the ambient air. Potassium was not subject to any significant loss, and the measured recovery in the solid evaporation product was 98%. Evaporation rates ranged between 50 g m−2 h−1 (RH = 82±13%, T = 12±6°C) and 130 g m−2 h−1 (RH = 60±19%, T = 24±5°C) in the three field tests. Apart from some disturbances due to low supply of Ca(OH)2, the urine module functioned without any substantial failures and was simple to maintain. The minimum consumption of Ca(OH)2 at full capacity was 6 g·L−1 urine and the electricity demand was 150 Wh kg−1 water evaporated from urine, resulting in operational costs of 0.05 EUR pers−1 d−1.Michel E. RiechmannBonginkosi NdwandweEsther E. GreenwoodEva ReynaertEberhard MorgenrothKai M. UdertElsevierarticleField testingResource recoveryUrine stabilizationCalcium hydroxideSource separationBlue Diversion AutarkyEnvironmental technology. Sanitary engineeringTD1-1066ENWater Research X, Vol 13, Iss , Pp 100124- (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Field testing Resource recovery Urine stabilization Calcium hydroxide Source separation Blue Diversion Autarky Environmental technology. Sanitary engineering TD1-1066
spellingShingle	Field testing Resource recovery Urine stabilization Calcium hydroxide Source separation Blue Diversion Autarky Environmental technology. Sanitary engineering TD1-1066 Michel E. Riechmann Bonginkosi Ndwandwe Esther E. Greenwood Eva Reynaert Eberhard Morgenroth Kai M. Udert On-site urine treatment combining Ca(OH)2 dissolution and dehydration with ambient air
description	We present the results of three field tests and three laboratory tests of a new physical-chemical urine treatment system, which can recover all nutrients, while pathogens are inactivated. The system consists of two steps. In the first reactor, biological processes including urea hydrolysis are prevented by mixing fresh urine with calcium hydroxide (Ca(OH)2). Due to the high pH value and the high availability of calcium, phosphate can be recovered by precipitation. The high pH value also fosters the inactivation of microorganisms, including pathogens. In the second reactor, water is evaporated at low energy consumption by blowing unheated ambient air over the stabilized urine. Stabilization in the first reactor was successful in all field and laboratory tests. The pH value remained between 12 and 13, except for short dips due to shortages of Ca(OH)2. Nearly all phosphorus (92-96%) precipitated and could be recovered as calcium phosphate in the first reactor, while nitrogen and potassium overflowed with the urine into the evaporation reactor. The efficiency of the second treatment step was very different for field and laboratory experiments and depended on the duration of the experiment. During a four-day laboratory test, nitrogen recovery was 98%. In contrast, nitrogen recovery was only around 20% in the long-term field experiments. The high nitrogen losses occurred, because biological urea hydrolysis was not inhibited anymore, when the pH value in the second reactor decreased due to the dissolution of high amounts of carbon dioxide from the ambient air. Potassium was not subject to any significant loss, and the measured recovery in the solid evaporation product was 98%. Evaporation rates ranged between 50 g m−2 h−1 (RH = 82±13%, T = 12±6°C) and 130 g m−2 h−1 (RH = 60±19%, T = 24±5°C) in the three field tests. Apart from some disturbances due to low supply of Ca(OH)2, the urine module functioned without any substantial failures and was simple to maintain. The minimum consumption of Ca(OH)2 at full capacity was 6 g·L−1 urine and the electricity demand was 150 Wh kg−1 water evaporated from urine, resulting in operational costs of 0.05 EUR pers−1 d−1.
format	article
author	Michel E. Riechmann Bonginkosi Ndwandwe Esther E. Greenwood Eva Reynaert Eberhard Morgenroth Kai M. Udert
author_facet	Michel E. Riechmann Bonginkosi Ndwandwe Esther E. Greenwood Eva Reynaert Eberhard Morgenroth Kai M. Udert
author_sort	Michel E. Riechmann
title	On-site urine treatment combining Ca(OH)2 dissolution and dehydration with ambient air
title_short	On-site urine treatment combining Ca(OH)2 dissolution and dehydration with ambient air
title_full	On-site urine treatment combining Ca(OH)2 dissolution and dehydration with ambient air
title_fullStr	On-site urine treatment combining Ca(OH)2 dissolution and dehydration with ambient air
title_full_unstemmed	On-site urine treatment combining Ca(OH)2 dissolution and dehydration with ambient air
title_sort	on-site urine treatment combining ca(oh)2 dissolution and dehydration with ambient air
publisher	Elsevier
publishDate	2021
url	https://doaj.org/article/df19303c85b048afb653a740a5d27996
work_keys_str_mv	AT micheleriechmann onsiteurinetreatmentcombiningcaoh2dissolutionanddehydrationwithambientair AT bonginkosindwandwe onsiteurinetreatmentcombiningcaoh2dissolutionanddehydrationwithambientair AT estheregreenwood onsiteurinetreatmentcombiningcaoh2dissolutionanddehydrationwithambientair AT evareynaert onsiteurinetreatmentcombiningcaoh2dissolutionanddehydrationwithambientair AT eberhardmorgenroth onsiteurinetreatmentcombiningcaoh2dissolutionanddehydrationwithambientair AT kaimudert onsiteurinetreatmentcombiningcaoh2dissolutionanddehydrationwithambientair
_version_	1718400682086629376

On-site urine treatment combining Ca(OH)2 dissolution and dehydration with ambient air

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