VUNA Handbook on Urine Treatment - PDF document

1 VUNA Handbook on Urine Treatment 2 Versi
VUNA Handbook on Urine Treatment 2 Version:The VUNA Project was carried out by: 3 VUNA – Urine Treatment ProcessesTable of Contents in urine. This process developed as a pilot in the VUNA Project losses and malodour. Electrolysis (p. 15) VUNA studied new methods to monitor nitrite in urine treatment processes, dgecwug vjg kpvgtogfkcvg pkvtkvg eqortqokugu rtqeguu uvcdknkvy0 nutrients from urine. This section presents certain processes including their ghhgevkxgpguu cpf hgcukdknkvy0 Urine Analysis (p. 20)vjku ugevkqp vq ghhgevkxgny ucorng. ogcuwtg. qt gxgp uypvjgukug wtkpg0 Struvite Precipitation (p. 16) StoredUrine StoredUrine Treated StoredUrine Treatment Process Control Stripping Adsorption Ca(OH)2 addition Freeze-Drying Urine Fertiliser PhosphorusDeprived Mg2+ StabilisedUrine Water VUNA NutrientSolution ExcessSludgePower SupplyOffGasStruvitePowderAeration Distiller phosphorus fertiliser.VUNA developed +++++----- PO NH Electrolysis CellStruviteReactorColumn Mg for bene�cial reuse. Table 1 attributes bene�cial reuses and poof urine treatment is to maximise bene�cial reuse while minimisTable 1: Compound Water N Nitrogen(present as NH+) Smell and toxicity of gaseous ammonia

2 P Phosphorus3-)Environmental pollution
P Phosphorus3-)Environmental pollution (eutrophication) K Potassium+)Salinisation of agricultural soils and groundwater Ca Calcium2+)Precipitates block pipes and valves (with phosphates). Mg Magnesium2+)Precipitates block pipes and valves (with phosphates). S SulphurEnvironmental pollution (in excessively high concentrations only) B Fe Zn Mo Mn Cu Micro-nutrients Environmental pollution (in excessively high concentrations only) HCO3– Bicarbonate3–)NonePrecipitates block pipes and valves SALT Sodium chlorideRaw product for Salinisation of agricultural soils and groundwater C C C Bulk organic substancesNonePungent smell. Treatment problems, e.g. foaming 2O production (pollutants, climate gases) PharmaceuticalsNoneHuman health concerns PathogensNoneHuman health concernsUrine is a complex mixture of numerous substances. All together - 5 The �rst process is Struvite Precipitation (p. 16)gen and potassium, remain in the ef�uent and pathogens are Complete Nutrient Recovery (p. 6)a combination of nitri�cation and distillation. This process Vgejpqnqikgu hqt vjg vtgcvogpv qh uqwteg/ugrctcvgf wtkpg kp vjg gVjgmykpk owpkekrcnkvy0Table 2: Main productStruvite (phosphate

3 mineral)MgNH4PO4·6H2OConcentrated nutri
mineral)MgNH4PO4·6H2OConcentrated nutrient solutionLiquid without ammonia, organic Primary nutrient P N Medium, mainly phosphate N P K + all other nutrientsHigh, nearly all nutrientsNone, Primary nutrient P N K + other nutrientsLow, little ammonia volatilization N P K + other nutrients High, ammonia is oxidised to N2Sanitisation/ Medium, depends on drying Complete (during distillation) Medium, due to chlorinationMalodour removalNoYesYesPharmaceuticals No degradation ?Unknown degradation Energy demand* Very low (manual reactor) Low (automated reactor) Medium ~ 50 Wh·Lurine-1~ 100 Wh·Lurine-1 distillation Volume reduction High Urine to struvite: HighLiquid volume:No volume reductionOther outputsPhosphate depleted urineDistilled water, excess sludgeOff-gas with chlorinated by-productsProcess Low (manual reactor) Medium (automated reactor) High LowDevelopment level High High The third process is Electrolysis (p. 15). This process could priate electrodes and voltages are used. However, nitrogen is ry, struvite precipitation and nitri�cation/distillation have already been operated at pilot scale. For more details refer to the rec 6 while still allowing oxygen to diffus

4 e to lower bio�lm layers. the
e to lower bio�lm layers. they �oat beneath the surface in absence of any agitation. A ers. The VUNA reactors used the Kaldnes K1 type carriers Nutrients [g]Nutrients [g]Nutrients [g]Nutrients [g] urea-N 1.8 NH4-N 1.8PO4-P 0.1SO4 0.3K 0.5 freshstored 0.03 L 50Wh 80Wh Storage Collection Nitrification Distillation electrical energy input:electrical energy input: NH4+-N 0.9 NO3--N 0.9 PO4-P 0.1SO4 0.3K 0.5 NH4+-N 0.9NO3--N 0.9 Polyethylene biomass carriers provide a large The complete nitri�cation process developed by the VUNA Project Approximately 50% of the total ammonia (NH) by bacteria. Simultaneously, about 90% of the organic to 5% of its initial volume. The remaining concentrated liquid A moving bed bio�lm reactor (MBBR) holds a large number of small plastic biomass carriers (Figure 2) to provide a large surface for bacterial growth. By providing this surface, slow-growtor. The selection occurs as bacteria growing on carriers bene�t pension are washed out faster. MBBR are typically �lled to about % of their bulk volume with biomass carriers. Lower �lling growth, thus result in lower conversion rates. Higher �lling rates

5 (above 60%) impede proper mixing of the
(above 60%) impede proper mixing of the reactor contents and 7 carefully adapted to new situations. Furthermore, the technology of urine per day. This corresponds to the average urine �ow at Eawag’s main building, Forum Chriesbach (see Links). The i.e. once at the Newlands-Mashu Field Test Site and once at the Urine storage tank: Attenuates �uctuations and ensures Pkvtk�ecvkqp eqnwop: Stores the (partially) nitri�ed urine Vacuum distiller: Final product storage and recycling: Hqtwo Ejtkgudcej – Gcyci’u ockp dwknfkpi:yyy0hqtwoejtkgudcej0gcyci0ejyyy0gcyci0ej1�ngcfokp1Fqockp31Cdqwv1Pcejjcnvki1hqtwo Rainwater StorageWCWCWCWCWC VUNA to be taken into account8 From the urine collection from the toilet users to the use of the �nal products, i.e. the concentrated nuhas a footprint of approximately 5modating it should not be smaller than 10. Although the three the basement. Rainwater is used to �ush the toilets (Figure 3). Customer Care Centre: At present, 3 waterless urinals are At a later stage, when new urine-diverting �ush toilets will be 8 Producer of the vacuum distiller used in the VUNA pilots:www.kmu-loft.dewww.solarspr

6 ing.devessels for the nitri�c
ing.devessels for the nitri�cation reactor. As the reactors were to be visitors. However, other plastic materials, such as PP or PE are also suitable for the reactor construction. The column was �lled with a bulk volume of 60% biomass carriers to form a movThe volume of the nitri�cation reactor has to be calculated urine and the maximum nitri�cation rate. In the VUNA reactors, the maximum nitri�cation rate varied from 100 to 800 mg/L/d (as to 4mg/L (as ammonium-nitrogen), one column of 120Important factors in�uencing the maximum nitri�cation rate are temperature and the maturity stage of the bio�lm. To operate unBetter rates were obtained at higher temperatures comprised between 25 and 30°C. The VUNA reactors repeatedly featured (see 1.3 Nitri�cation Start-up Procedure, p. 10), before they dropped back to rather low rates (100mg/L/d) due to limited the case of nitri�ed urine, water is the component with the lowest boiling point. Hence, at a certain temperature, water evaporates natively, an increased concentration of the nutrient solution can Membrane distillation: A gas-permeable membrane lets water For

7 the VUNA pilots, we opted for an indust
the VUNA pilots, we opted for an industrial vacuum distiller, ly 85°C. This had the signi�cant advantage of being below the Germany (see Links). The distiller uses vapour compression to to achieve an optimal energy ef�ciency. An additional heat exin�owing urine, thus cooling the distillate and pre-heating the ci�c energy consumption of 100Wh/L treated urine. Compared to the nitri�cation reactor, the distiller’s capacity is about one market. With the alternative processes described, alternative Vqvcn pwvtkgpv tgeqxgty htqo wtkpg – qrgtcvkqp qh c rknqv/uecng pkvtk�ecvkqp tgcevqt0 htqo uqwteg/ugrctcvgf wtkpg dy pkvtk�ecvkqp cpf fkuvknncvkqp0 VesselVapour 9 The in�uent pump is controlled by the pH value in the nitri�cation The air required to aerate the nitri�cation reactor can either be The nitri�cation reactor should sit in a retention basin able to retain one complete reactor volume in case of spills or breakages. The room with the reactors should have a �oor drain linked to a 2. Intermediate storage tankssoak pit or a sewer, to quickly evacuate any spills (Figure 7). The �

8 066006C;oor drain should immediately be
066006C;oor drain should immediately be followed by a p-trap to prevent The initial urine storage tank (Figure 6) should be sized in order to attenuate any daily, weekly or even seasonal �uctuations, as the nitri�cation process requires a steady input. The intermeDepending on the reactor size, the in�uent pump, the air comnitri�cation volume, a 400 V 3-phase connection will be necesSafety, p. 13), the room has to be suf�ciently ventilated. A addition to the normal room ventilation. Suf�cient air space for 1 1 2 2 3 5 6 7 8 9 10 VUNA started up three pilot nitri�cation plants8 the �rst one Newlands-Mashu Field Test Site in eThekwini, and the third The main drivers of the nitri�cation process are the nitrifying ideal growth conditions. To initiate the process of growing nitrifying bacteria in urine, we �rst need to source a suitable bacteria population. In the VUNA nitri�cation reactors, we ipal wastewater treatment plants (Figure 8). Given that the substrate concentrations in municipal wastewater are about 100 times lower compared to urine, the bacteria �rst had to Calculate the amo

9 unt of urine necessary to reach a total
unt of urine necessary to reach a total Set the pH control to switch on the in�uent urine pump, 11 Set the aeration rate to maintain a well stirred nitri�cation column and a dissolved oxygen level above 4 mg/L. A rotameter can be For details on laboratory analyses of chemical parameters to be It is assumed that the nitri�ed urine leaving the reactor into the intermediate storage tank has a composition equal to the one in If the concentrate is mixed in a concentrate holding tank, a comAs micro-nutrients are an important component in the concenWeekly to monthly (depending on stability of signals): Yearly: omitted in industrial plants. We expect the costs to signi�cantly Vcdng 5: Equvu kp UC [ZCT]Total 12 side product at up to 97% of the initial urine volume. Although mg/L is typical. Also, a thin oil layer can sometimes be observed �oating on the distillate. It originates from tiny leakages Vqkngv �wuj ycvgt: into the toilet �ush water storage. Normally, the distillate is diin the toilet �ush water tank. In an extreme case, when the However, even at such low levels, no odours or other comprobetween relevant standards on battery

10 water and the distillate tillate and an
water and the distillate tillate and an ammonium sulphate solution is produced, which Vcdng 6: Uqwvj Chtkec,Ucetk�ekcn cpqfg:�ector in the main distillation vessel. It had to be removed after which activates the vacuum pump at given intervals for 1 second. One-hour intervals were found to be suf�ciently short to In general, the distiller was inspected and serviced twice a year, Vcdng 7: NOPOKNaCl2.12.10.21.71.33.1SOCaB0.80.040.0040.0020.001only distiller component susceptible to corrosion. 13 Compounds causing signi�cant environmental and health conWhen storing large volumes of urine containers, contact with the air, signi�cant amounts of ammonia volatilise. During the nitri�cation process, nitrite may accumuAmmonium nitrate:um nitrate is highly explosive. Also, when in solution maximum and distillation process. Nevertheless, critical compounds may Ammonia is a strong irritant to the respiratory system depending on its concentration. In large urine storage tanks, ammonia can accumulate in the headspace and become a health hazard, if always wear adequate protective equipment, such as a mask In the case of nitrite accumulation during the nitri�

11 660069;cation protrate, before the solut
660069;cation protrate, before the solution is distilled. As nitrite is toxic for plants, it must not be contained in the �nal fertiliser product. In the case of high nitrite concentrations in the nitri�cation reactor, nitrogen tri�cation process is not solely an issue compromising process Ammonium nitrate is thermally unstable, i.e. it decomposes viotemperature of 130°C will not be exceeded. We therefore recal., 2015 for details). Thus, one has to ensure that suf�cient Under normal operating conditions in vacuum distillers, the ever, in the case all liquid accidentally be evaporated, the temGiven its thermal instability, ammonium nitrate is regulated in in the concentrated nutrient solution can further increase the risk of thermal decomposition: Chloride and organic substances. In South Africa: and regulated as explosives, if they a) contain > 25% nitrogen or b) contain > 16% of nitrogen and > 0.4% combustible maIn the European Union and Switzerland: fertilisers with > 16% nitrogen may only be sold to farmers and professional gardeners (EEC, 2008) and with > 28% nitrogen face a series of other restrictions on pH, chloride content (max. 0.02%), particle size, and combu

12 stible material content tion (4.2% nitro
stible material content tion (4.2% nitrogen) is suf�ciently low that no further measures sionals (other limits do not apply below 28% nitrogen content). exceeded in the dried solid (approximately 0.5%). Thus a solid would have to be declared as an explosive entailing complex legal procedures and dif�cult handling, except if it was mixed with limestone. This is a common practice for commercial fertilisers. cpf Cooqpkwo Pkvtcvg0Gzrnqukxgu Cev0 The complete nutrient recovery relies on a functioning nitri�cation process. Therefore, mechanisms underlying nitri�cation of Fumasoli (formerly Hug) carried out her PhD research on “Stabilisation of urine with nitri�cation as pre-treatment for nutrient recovery” (Fumasoli, 2016). The following paragraphs present ammonium oxidising bacteria (AOB) decrease or even cease in urine nitri�cation plants, because “related ammonia oxidizing bacteria causes strong acidi�cationin high strength nitrogen wastewater” (Fumasoli et al., 2016). Based on their �ndings, the team developed guidelines for a “Stable ammoniaconversion to nitrate and the prevention of unfavourable system states durin

13 g nitri�cation of urine” (F
g nitri�cation of urine” (Fumasoli et al., 2016). Details on nitri�cation rates, bacterial growth and further mechanisms in the pilot nitri�cation reactor are summarised in the publication “Complete nutrient recovery from urine in a pilot-scale of partial nitri�cation – as it occurs in the VUNA pilot plants, limited by the natural alkalinity in urine – with complete nitri�cation, i.e. a conversion of 100% ammonium to nitrate by adding a base (Uhlmann, 2014). She found that complete nitri�cation did neito partial nitri�cation. It was rather temperature �uctuations that Fumasoli, A., Morgenroth, E., Udert, K.M. (2016) Uvcdng cooqpkceqpxgtukqp vq pkvtcvg cpf vjg rtgxgpvkqp qh wphcxqtcdng J., Morgenroth E., Udert K.M. (2016) Vjg itqyvj qh pkvtquqeqeewu/tgncvgf cooqpkc qzkfkzkpi dcevgtkc ecwugu uvtqpi cekfk�ecvkqpkp jkij uvtgpivj pkvtqigp ycuvgycvgt0 Submitted to Eqorngvg pwvtkgpv tgeqxgty htqo wtkpg kp c rknqv/uecngecvkqp qh uqwteg/ugrctcvgf wtkpg0 To concentrate the nitri�ed urine, distillation was selected as a of concept that the combination of nitri�cation and distillation cation on â€

14 œComplete nutrient recovery from source-
œComplete nutrient recovery from source-separated urine by nitri�cation and distillation” (Udert & Wächter, 2012) potential in terms of energy ef�ciency, recovery rates, and process Safety, p. 13). For a comprehensive documentation of safety aspects during distillation, as well as a description of the underlying experiments, refer to the publication “Safety assessment for production and storage of nitri�ed and concentrated how sodium chloride can be removed from nitri�ed urine by selective crystallisation. Given that both sodium and chloride Vgorgtcvwtg fgrgpfgpv tgoqxcn qh 15 ing through the urine transforms certain substances. The techsystems, as it requires only a small space. In addition, one can “Electrolysis for the treatment of stored source-separated urine” processes (Figure 10) at three different levels of anode potential. Besides the anode potential, another important parameter in�uencing the process is the electrode material. The following and gaseous nitrogen. In their publication “Direct electrochemshowed that graphite anodes are suitable, as they are suf�ciently selective, i.e. they only convert the targeted substances, i

15 n ti�ed an “Inhibition of d
n ti�ed an “Inhibition of direct electrolytic ammonia oxidation due oxide �lms (TDIROF), which had been shown to be catalytically tion, the researchers propose a modi�ed electrolysis cell design nia to nitrate or gaseous nitrogen. Refer to “Electrochemical oxby-products formation8 Christina Fritzsche and Annette Remmele. For details refer to their master’s theses or to the publication summarising the results “Formation of chlorination by-products Rwdnkecvkqpu qp Gngevtq/Ejgokecn Wtkpg Vtgcvogpv:fwtkpi gngevtqnyvke wtkpg vtgcvogpv0Kpjkdkvkqp qh fktgev Environmental Science and Technology, 49(18), 11062-11069. By-productsPower supplyChlorinatedorganicsOrganicSubstancesIndirectoxidationAnode potentialDirectoxidatione–e–e–N2N2Cl2, HOCl, OCl–ClO3–ClO–NO3–NO3–NH3NH3Cl–Anode Processes occurring at an anode in urine vary Slow ! 16 Struvite Precipitationadd magnesium and �lter the precipitated powder from the (12.5%) containing some magnesium (10%) and nitrogen (5%), uct (Figure 11). Thus, struvite precipitation has to be combined tal and the eThekwini Municipality around Maximilian Grau, Sara developed two struvite reacto

16 rs for �eld applications. The
rs for �eld applications. The following paragraphs present an overview of their work and direct you to relevant documents and publications. For an overview and comparison of different processes, refer to “Technologies The �rst struvite reactor in eThekwini was adapted from the PVC, and was thus corrosion-proof. A sight glass and sturdy pipe connections enabled a convenient operation (Figure 12) For complete account on the struvite reactors in eThekwini, refer to the conference contributions “Nutrient recovery from urine8 Operation & optimization of reactors in eThekwini” (Grau et al., Filtration & Drying Nutrients [g]Nutrients [g] urea-N 1.8PO4-P 0.3SO4 0.3K 0.5 -N 1.8 2.4 g struvite powder 1 Leffluent Storage Collection Struvite Precipitation Mg2+ 0.4 NH4+-N 0.1 PO4-P 0.3Mg2+ 0.4 SO4 0.3 K 0.5 NH4+-N 1.7 magnesium input: Hkiwtg 33:tinued developing an automated reactor, to improve ef�ciency nesium has to be dosed according to laboratory measurements described in “Development of a fully automated struvite reactor project, the researchers at Eawag assessed “Struvite precipitation from urine with electrochemical magnesium dosage” (Figure 14; Hug & Udert, 2013) as well

17 as the option to use “Pretreatmalanga.
as the option to use “Pretreatmalanga. Alternatively “Wood ash as a magnesium source for phosphorus recovery from source-separated urine (Sakthivel et al., 2012) was also studied, but did not yield satifactory results. 17 UVWP – Uvtwxkvg htqo Wtkpg kp Pgrcn – VWPC’u rtgewtuqt project developed a low-cost struvite reactor. A construction and www.eawag.ch/stunwww.phosphorusplatform.euwww.ostara.chwww.saniphos.euyyy0pwtguyu0qtiwww.multiformharvest.com VWPC Rwdnkecvkqpu qp Uvtwxkvg Rtgekrkvcvkqp htqo Wtkpg:Grau, M.G.P., Rhoton, S., Brouckaert, C.J., Buckley, C.A. (2015)Vgejpqnqikgu hqt vjg vtgcvogpv qh uqwteg/ugrctcvgf wtkpg kp vjg gVjgmykpk Owpkekrcnkvy0Nqy/equv uvtwxkvg rtqfwevkqp wukpi uqwteg/ugrctcvgf wtkpg kp Pgrcn0 Hug, A., Udert, K.M. (2013) Uvtwxkvg rtgekrkvcvkqp htqo wtkpg Wqqf cuj cu c ugrctcvgf wtkpg0 Science of the Total Environment, 419, 68-75.Odour emissions are reduced by a completely enclosed �lter. 18 As indicated in the previous chapter on urine nitri�cation (2 Nitri�cation, p. 14), nitrite accumulation is a severe threat to a stable process operation. As currently no methods are available Group at Eawag assessed two methods to detect the nitrite conUltr

18 aviolet (UV) spectrophotometricuting UV
aviolet (UV) spectrophotometricuting UV light absorption at a speci�c wavelength to nitrite Intelligence and Control at Eawag. For the VUNA Project, Alma Mašic´ and Kris Villez coordinated the studies on nitrite detection. Their comprehensive website (see Link Section) contains prevent irreversible failure of urine nitri�cation reactors. Alurine. The SPIKE researchers showed that “Estimation of nitrite in source-separated nitri�ed urine with UV spectrophotometry” (Mašic´numerous experiments at laboratory and pilot scale. Four masHess, Elisabeth Grimon, and Katja Briner (see Publications Seccaused by nitrite respectively nitrate. In nitri�ed urine, nitrate is present at high concentrations. Therefore, detecting nitrite at concentrations, which are 3 orders of magnitude lower, requires speci�c algorithms taking into account several measured wavecentration in the nitri�cation reactor knowing the momentary and results are best summarised in “Model-based observers for monitoring of a biological nitri�cation process for decentralized Rwdnkecvkqpu qp Rtqeguu Eqpvtqn kp Wtkpg Vtgcvogpv:Ecnkdtcvkqp qh c WV/Vku urgevtqrjqvqogvgt

19 Hgcukdknkvy qh WV/Vku urgevtqrjqvqogvty
Hgcukdknkvy qh WV/Vku urgevtqrjqvqogvty ykvj WV urgevtqrjqvqogvty0tgcevqt dy ogcpu qh WV urgevtqrjqvqogvty0on Nutrient Removal & Recovery, 18-21 May, Gdansk, Poland.Gxcnwcvkqp qh WV/urgevtqrjqvqogvty www.eawag.ch/en/department/eng/main-focus/sensors-and-automation 19 Rwdnkecvkqpu qp Ovjgt Wtkpg Vtgcvogpv Rtqeguugu (Dgyqpf VWPC):C pqxgn crrtqcej hqt uvcdknkzkpi htguj wtkpg dy ugrctcvkqp cpf fgegpvtcnkzcvkqp hqt ycuvgycvgt ocpcigogpv0Maurer, M., Pronk, W., Larsen, T.A. (2006) Vtgcvogpv rtqeguuguMorales, N., Boehler, M.A., Buettner, S., Liebi, C., Siegrist, H. Tgeqxgty qh pkvtqigp cpf rjqurjqtwu htqo wtkpg dy uvtwxkvg rtgekrkvcvkqp hqnnqygf dy eqodkpgf uvtkrrkpi ykvj Schielke-Jenni, S. (2015) Fgegpvtcnkugf wtkpg vtgcvogpv ykvj Vjg Cwvctmy vqkngv eqodkpkpi uvcdknkucvkqp qh wtkpg dy nkog yyy0cwvctmy0ejin the VUNA Project were8 nitri�cation, distillation, electrolysis, and struvite precipitation. Researchers around the world have tested other processes to recover nutrients from urine. This secfor your urine. For an extended overview on urine treatment proGiven that struvite precipitation recovers mainly phosphorus, but vided, in order to achieve a satisfactory ef�uent quality. Stripping has been

20 tested in various projects to recover a
tested in various projects to recover ammonia from ammonia-rich wastewater. In this process, air is forced through urine jected into a tank containing sulphuric acid, which at its turn, reacts with the gaseous ammonia to form an ammonium sulphate solution. ment plant near Eawag for the “Recovery of nitrogen and phosphoAs part of the Autarky Project (see Link Section), “A novel ap(Krähenbühl et al., 2016) has been developed. The process is to be integrated directly into the toilet (Figure 16), as lime inhibits In the Autarky Project, the urine stabilised by lime is humidi�ed8 �owing through a ventilated pipe, the liquid evaporates at ambi“Decentralised urine treatment with the nitritation/anammox proAlthough published a decade ago, the review “Treatment proprovides an extensive overview of potential urine treatment proscribed in this manual8 freeze-thawing, reverse osmosis, acidi�cation, ion-exchange, electro-dialysis, nano-�ltration, ozonation.waste streams with high ammonium content, such as liquid manure, land�ll leachate, or digester supernatant. On the other 20 ment processes. In certain cases, it is necessary to produce synthetic urine, to st

21 udy speci�c mechanisms. With
udy speci�c mechanisms. With synthetic chapter also presents recipes for synthetic stored and nitri�ed Eqorngvg pwvtkgpv tgeqxgty htqo wtkpg kp c rknqv/uecngTypical Concentrationsfactors in�uencing every individual. In the VUNA Project, urine was collected at various places from numerous individuals over an extended period of time. Therefore, �uctuations are not as be representative for an of�ce building. Contrarily to a housing unit, concentrations in an of�ce building might be lower, given that the most concentrated urine is excreted just after people get up in the morning and urinate the �rst time in a day. Hence, In addition to the daily �uctuations, �ush water has an important lets do require some �ush water to convey the faecal matter into the conventional sewer. A small proportion of this �ush water may in�ltrate into the urine pipe, if the urine-diverting valve is not perfectly water-tight. As men use waterless urinals with no risk of water in�ltration into the urine pipe, less water enters the men’s urine collection tank, thus the nutrient concentration in the

22 men’s Vcdng 8: 50 Wqogp’u vcpm60
men’s Vcdng 8: 50 Wqogp’u vcpm60 Ogp’u vcpm 21 For laboratory experiments, synthetic urine may replace real thetic urine in the laboratory. These recipes reduce the components contained in urine mainly to the most important minerals. Depending on the recipe, only urea (fresh urine – Table 7) and pounds. The recipe for nitri�ed urine (Table 9) does not contain Vcdng 9: been hydrolysed into ammonium and carbon dioxide. Also, hood! Add the NHOH solution with a volumetric cylinder or a glass pipette, but not with a micro-pipette with plastic tips, as Vcdng 8: For experiments on distillation or fertiliser trials, it might be of qualities of nitri�ed urine. The recipe in Table 9 is based on the ammonia, 25% of the total ammonia volatilised and 50% of the Vcdng ;: ComponentIonWater (H2O)1 LNH4-NNH4NO3 19.2 gNO3-NNaH2PO4·2H2O 2.7 gPO4-PKCl3.4 gKKHCO31.1 gSO4Na2SO4 anhydrous2.3 gClNaCl3.6 gNa0.4 mLTIC Udert, K.M., Wächter, M. (2012)  Water Science & Technology, 54(11-12), 413-420. Editors: Bastian Etter, Kai M. UdertContact: Etter, B., Udert, K.M. (2015) VUNA handbook on urine treatment. Eawag, Dübendorf, Switzerland VUNA – Urine Treatment Processes VUNA – Urine Treatment