Complete nutrient recovery from source-separated urine by nitrification and distillation

Udert, Kai M.; Wächter, Michael

doi:10.1016/j.watres.2011.11.020

Cited by 257 publications

(182 citation statements)

References 29 publications

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“…We demonstrate the developed method by means of data collected during a single cycle of an intermittent flow stirred-tank reactor for biological urine nitrification (Udert and Wächter, 2012;Fumasoli et al, 2016). This cycle starts with a short feeding of source-separated urine collected at Eawag with No-Mix toilets (Larsen et al, 2001).…”

Section: Problem Statementmentioning

confidence: 99%

Extent computation under rank-deficient conditions

et al. 2017

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The identification of kinetic models can be simplified via the computation of extents of reaction on the basis of invariants such as stoichiometric balances. With extents, one can identify the structure and the parameters of reaction rates individually, which significantly reduces the number of parameters that need to be estimated simultaneously. So far, extentbased modeling has only been applied to cases where all the extents can be computed from measured concentrations. This generally excludes its application to many biological processes since the number of reactions tends to be larger than the number of measured quantities. This paper shows that, in some cases, such restrictions can be lifted. In addition, in contrast to most extent-based modeling studies that have dealt with simulated data, this study demonstrates the applicability of extent-based model identification using laboratory experimental data.

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Section: Problem Statementmentioning

confidence: 99%

Extent computation under rank-deficient conditions

et al. 2017

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“…6,8 Due primarily to the fecal contamination of sourceseparated urine, 9 handling of urine and direct application as fertilizer in agriculture can pose microbial health risks. 10 Storage of urine for 6 months at 20°C is recommended prior to handling and usage in order to reduce or eliminate the risks.…”

Section: Introductionmentioning

confidence: 99%

“…14 In configurations where nitrification is applied in combination with evaporation, a concentrated solution that preserves nearly all nutrients in the urine can be produced. 15 Pilot reactors for combined nitrification/distillation systems are operated at eThekwini Water and Sanitation in Durban, South Africa and at the Swiss Federal Institute of Aquatic Science and Technology (Eawag) in Dübendorf, Switzerland as part of the Valorisation of Urine Nutrients in Africa (VUNA) project. 13 Nitrification of urine, i.e., the oxidation of ammonia (NH 3 ) to nitrate ĲNO 3 − ), prevents ammonia volatilization, enhancing the recovery of nitrogen in urine.…”

Section: Introductionmentioning

confidence: 99%

Inactivation kinetics and mechanisms of viral and bacterial pathogen surrogates during urine nitrification

Bischel

Schertenleib

Fumasoli

et al. 2015

Environ. Sci.: Water Res. Technol.

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a This paper assesses the inactivation performance and mechanisms in urine nitrification reactors using bacteria and bacteriophages as surrogates for human pathogens. Two parallel continuous-flow moving bed biofilm reactors (MBBRs) were operated over a two-month period. One MBBR was used to conduct a continuous spike experiment with bacteriophage MS2. The second reactor provided the matrix for a series of batch experiments conducted to investigate the inactivation of Salmonella typhimurium, Enterococcus spp., MS2, Qβ, and ΦX174 during urine nitrification. The roles of aeration, biological activity, and solution composition in inactivation were evaluated. Whereas bacteriophages ΦX174 and MS2 remained infective following urine nitrification, partial inactivation of bacteriophage Qβ was observed. Qβ inactivation was attributed primarily to aeration with a potential additive effect of biological processes, i.e., processes that are attributable to the presence of other microorganisms such as sorption to biomass, predation or enzymatic activity. Tailing of Qβ inactivation to a plateau indicated a protective effect of the solution components in aerated nitrification reactors. In contrast to the bacteriophages, S. typhimurium and Enterococcus spp. were mainly affected by biological processes: they were inactivated in biologically active nitrification reactors while remaining stable in chemically equivalent filtered controls. The tested bacteria could, for example, be out-competed by other microbial communities or sorbed to biomass in the reactor. Microbial communities did not adapt to inactivate bacteriophage MS2 (e.g., via increased prevalence of virus predators) in the experimental time-scale evaluated, with no observed inactivation of MS2 during continuous input for 51 days in the flow-through MBBR. The compilation of these results suggests that biological nitrification as a fertilizer production process remains insufficient as a stand-alone technology for the sanitization of source-separated urine.

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“…EWS had already installed urine tanks on 300 UDDTs and was collecting urine in three communities, so these became the control areas. The urine was being collected for related research on nutrient recovery [34,35] within an interdisciplinary sanitation project (see www.vuna.ch). The 300 households in the control sample represented about 10% of the total households who had a UDDT (complete lists of all UDDTs installed in the areas were not available when the experiment started).…”

Section: Sample Selectionmentioning

confidence: 99%

The Impact of Conditional Cash Transfer on Toilet Use in eThekwini, South Africa

Tilley

Günther

2016

Sustainability

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Abstract:In the developing world, having access to a toilet does not necessarily imply use: infrequent or non-use limits the desired health outcomes of improved sanitation. We examine the sanitation situation in a rural part of South Africa where recipients of novel, waterless "urine-diverting dry toilets" are not regularly using them. In order to determine if small, conditional cash transfers (CCT) could motivate families to use their toilets more, we paid for urine via different incentive-based interventions: two were based on volumetric pricing and the third was a flat-rate payment (irrespective of volume). A flat-rate payment (approx. €1) resulted in the highest rates of regular (weekly) participation at 59%. The low volumetric payment (approx. €0.05/L) led to regular participation rates of only 12% and no increase in toilet use. The high volumetric payment (approx. €0.1/L) resulted in lower rates of regular participation (35%), but increased the average urine production per household per day by 74%. As a first example of conditional cash transfers being used in the sanitation sector, we show that they are an accepted and effective tool for increasing toilet use, while putting small cash payments in the hands of poor, largely unemployed populations in rural South Africa.

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Complete nutrient recovery from source-separated urine by nitrification and distillation

Cited by 257 publications

References 29 publications

Extent computation under rank-deficient conditions

Extent computation under rank-deficient conditions

Inactivation kinetics and mechanisms of viral and bacterial pathogen surrogates during urine nitrification

The Impact of Conditional Cash Transfer on Toilet Use in eThekwini, South Africa

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