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Abstract

International guidelines have been presented within the Sida financed EcoSanRes programme for the use of human urine and faeces in crop production based on the current knowledge on use of urine and fae- ces in small and large-scale cultivation. Urine and faeces are each a complete fertiliser of high quality with low levels of contaminants such as heavy metals. A basis for the recommendations for agricultural use is the knowledge of the contents of nutrients in the excreta, the amounts excreted, composition and plant avai- lability of the plant nutrients, as well as the good knowledge of how the product has been sanitised. Urine is a quick-acting nitrogen rich fertiliser that can be applied as it is or diluted. Faeces are rich in phospho- rous, potassium, micronutrients as well as organic matter. Well documented research in this area is needed.
GUIDELINES FOR THE USE OF HUMAN URINE AND FAECES
IN CROP PRODUCTION
A. Richert Stintzing1, H. Jönsson2, B. Vinnerås2, E. Salomon3
1VERNA, Malngårdsvägen 14, 116 38 Stockholm, Sweden. anna@verna.se
2Dept of Biometry and Technology, Swedish University of Agricultural Sciences, Box 7032,
750 07 Uppsala, Sweden
3Swedish Institute of Agricultural and Environmental Engineering, Box 7033, 750 07 Uppsala,
Sweden
ABSTRACT
International guidelines have been presented within the Sida financed EcoSanRes programme for the
use of human urine and faeces in crop production based on the current knowledge on use of urine and fae-
ces in small and large-scale cultivation. Urine and faeces are each a complete fertiliser of high quality with
low levels of contaminants such as heavy metals. A basis for the recommendations for agricultural use is
the knowledge of the contents of nutrients in the excreta, the amounts excreted, composition and plant avai-
lability of the plant nutrients, as well as the good knowledge of how the product has been sanitised. Urine
is a quick-acting nitrogen rich fertiliser that can be applied as it is or diluted. Faeces are rich in phospho-
rous, potassium, micronutrients as well as organic matter. Well documented research in this area is needed.
INTRODUCTION
Urine and faeces from human beings are valuable resources that deserve a better fate than to
end up in surface waters as well as groundwater, where they can cause significant problems. In
regions where there is a lack of domestic financing of fertilisers for subsistence production of
food, collected urine and faeces can contribute significantly to food security and health. Source
separated urine and faeces are collected in sanitation systems designed for this, e.g. urine diver-
ting toilet systems (Johansson et al, 2001). Treatment of urine and faeces in order to minimise
the hygiene risk is important, as well as guidelines for how to use the fertiliser in crop produc-
tion that will enable proper use with minimal risk for users of the system.
MATERIALS AND METHODS
These guidelines for use of urine and faeces in crop production have been produced through
collection of experiences, documented as well as undocumented, of reuse of urine and faeces as
fertiliser. Countries where human urine and or faeces have been studied are South Africa,
Zimbabwe (Morgan, 2003), Ethiopia, Mocambique, Benin, Burkina Faso, Senegal, Cote d´Ivoire,
Togo, Mali, Mexico (Guadarrama et al, 2001), China, Sweden (Kirchmann & Pettersson, 1995,
Johansson et al, 2001, Rodhe et al, 2004) and Germany (Simons & Clemens, 2004) although
many of these experiences are not yet scientifically published. The basis for the work has also
been current plant nutrient knowledge through a literature study. A reference group consisting of
international experts has been consulted in order to assure the relevance of the guidelines.
Dissemination of the guidelines is carried out though the publication of results at conferences, as
well as thought the Internet, and the guidelines can be downloaded at www.ecosanres.org. The
authors gratefully accept comments, as updating will need to take place continuously.
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Waste Management Strategies
RESULTS AND DISCUSSION
Recommendations for agricultural use of excreta are based on knowledge of the nutrient con-
tent of the excreta, the amounts excreted, and the treatment of the excreta, which influences their
properties. Table 1 shows the proposed default values for excreted mass and nutrients from one
person on a Swedish diet. Adapting of the guidelines to local conditions is necessary since diets,
as well as plant production conditions vary. Excreta should be handled and treated according to
hygiene guidelines for safe reuse (Schönning & Stenström, 2004) before use in cultivation.
Urine and faeces are each a complete fertiliser of high quality with low levels of contami-
nants such as heavy metals (Palmquist & Jönsson, 2004). Urine is rich in nitrogen, while faeces
are rich in phosphorous, potassium and organic matter.
Specific local recommendations for use of urine and faeces in cultivation should be based on
local recommendations for fertilisation of crops. Application rates for commercial mineral nitro-
gen fertilisers (urea or ammonium if available) can be used as a basis for recommendations on
the use of urine. Before translating such recommendations to urine, its nitrogen (N) concentra-
tion should preferably be analysed. Otherwise, it can be estimated at 3-7 g N per litre. If no local
recommendations can be obtained, a rule of thumb is to apply the urine collected from one per-
son during one day (24 hours) to one square metre of land and cropping period. If all urine is
collected, it will suffice to fertilise 300-400 m2of crop per person and year with N at a reasona-
ble rate. For most crops, the maximum application rate, before risking toxic effects, is at least 4
times this application rate. Urine also contains phosphorus, and it will suffice to fertilise up to
600 m2of crop per person and growing season, if the application rate is chosen to replace the
phosphorus removed, as for faeces below.
Urine can be applied neat or diluted. However, the application rate should always be based
on the desired nutrient application rate and any potential need for supplementary water should
be met with plain water. To avoid smells, loss of ammonia and foliar burns urine should be
applied close to the soil and incorporated as soon as possible. Irrigation after application of urine
is beneficial.
Urine is a quick-acting fertiliser whose nutrients are best utilised if the urine is applied from
prior to sowing up until two-thirds of the period between sowing and the harvest. The best fer-
tilising effect is achieved if urine and faeces are used in combination with each other, but not
necessarily in the same year on the same area. The amount of urine to be spread can be applied
in one large dose or in several smaller doses, and under most circumstances the total yield is the
same for the same total application rate.
For faeces, the application rate can be based on the local recommendation for the use of
phosphorous-based fertilisers. This results in a low application rate, and the improvement due
to the added organic matter is hard to distinguish. However, faeces are often in the smaller scale
applied at much higher rates, at which the structure and water-holding capacity of the soil are
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Sustainable Organic Waste Management for Enviromental Protection and Food Safety
Parameter Unit Urine Faeces
Wet mass kg/person,year 550 51
Dry mass kg/ person,year 21 11
Nitrogen g/ person,year 4000 550
Phosphorus g/ person,year 365 183
Table 1. Proposed new Swedish default values for excreted mass
and nutrients (Vinnerås, 2002).
visibly improved as an effect of its content of organic matter. Both organic matter and ash are
often added to the faeces and they improve the buffering capacity and the pH of the soil, which
is especially important on soils with low pH. Thus, depending on the application strategy, the
faeces from one person will suffice to fertilise 1.5-300 m2, depending on whether they are
applied according to their content of organic matter or phosphorus. Faeces should be applied and
mixed into the soil before cultivation starts. Local application, in holes or furrows close to the
planned plants, is one way of economising on this valuable asset.
Pharmaceuticals and hormones are excreted with the urine, and the discussion has been rai-
sed whether to restrict use of urine on this account. Documented effects of pharmaceutical resi-
dues almost entirely reported for aquatic systems, rather than terrestrial systems. Many reports
have been published on adverse effects on organisms in watercourses where wastewater is rele-
ased. However, soil microorganisms are better adapted to decomposing hormones and other
organic substances than are aquatic organisms and the soil-root barrier is very tight against orga-
nic molecules. Thus, the risk when using urine from human beings as fertiliser on soil is small,
since the microbes in the soil system are good at decomposing the excreted pharmaceutical resi-
dues. This will always be a better strategy for the environment than to emit the products into
aquatic systems, as is the case for conventional wastewater systems with WC.
Further research on the use of urine and faeces as fertilisers is needed, especially in the follo-
wing areas:
Nutrient effects of excreta on crops and soil
Fertilisation strategies and application techniques when using excreta
Efficiency of short term storage of urine in soil
Simple and resource-efficient sanitation techniques for faeces
These guidelines have been developed within the EcoSanRes programme, funded by Sida,
the Swedish International Development Cooperation. The full text of the guidelines can be
downloaded from www.ecosanres.org.
CONCLUSIONS
Reuse should be safe, e.g. the hygiene guidelines on use of excreta for crop production
(Schönning & Stenström, 2004) should be followed.
Urine and faeces supplement each other as fertilisers, urine is rich in nitrogen that is
quickly available, while faeces is rich in rich in phosphorus, potassium and organics and
its nutrients are not that readily available.
The chemical contamination of urine and faeces is minimal and the levels of e.g. heavy
metals are very low. Pharmaceuticals residues are excreted via urine and faeces.
However, the soil-root barrier is very efficient and therefore the risk with these substan-
ces is probably far smaller than that associated with e.g. insecticides, fungicides and her-
bicides applied to crops.
As these fertilisers contain all the elements removed from the field by the crop, their use
decreases both the need of soil analyses and the risk for soil depletion.
Reuse of urine and faeces as fertilisers essentially eliminates the risk that their nutrients
pollute the environment and it enables sustainable crop production.
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... In light of these considerations, human faecal sludge from ventilated improved pit latrines (VIP latrines) emerges as a viable alternative fertilizer due to its rich nutrient content and its ability to enhance soil quality (Nikiema et al., 2013). While human faeces have been recognized as a valuable nutrient source in several countries worldwide, including China, Japan, Korea, and various African and South American nations, its acceptance in Botswana remains limited, primarily utilized by select urban residents for landscaping and gardening purposes (Jönsson et al., 2004). Nevertheless, it is essential to acknowledge that faecal material represents a critical threat to human and animal health, as well as ecosystem integrity (Graham & Polizzoto, 2013). ...
... According to previous research, the annual quantity of sludge generated from pit latrines averages around 520 kg per person, primarily comprising urine and faeces (Jacks et al., 1999). Urine is rich in nitrogen, while faeces contain substantial phosphorous and potassium levels (Jönsson et al., 2004). Recycling this sludge into the soil can replenish these essential nutrients, sustaining land fertility and agricultural productivity (Jacks et al., 1999). ...
... However, the most undesirable consequence of such high nutrient concentrations is the risk of pollution which is posed by pit latrines. Several researchers have found that pit latrines are a source of nitrate contamination and therefore a hazard to groundwater due to their huge capacity to play a part in chemical and/or microbial pollution (Appiah-Effah et al., 2015;Gimeno-García et al., 1996;Graham & Polizzoto, 2013;Jacks et al., 1999;Jönsson et al., 2004;Mafa, 2003;Nikiema et al., 2013). Earlier studies carried out by Mafa (2003) in the city of Francistown in Botswana showed that pit latrines were found to have the highest impact on groundwater quality, resulting in such groundwater being unsuitable for consumption. ...
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Household wastewater can be divided into three fractions by origin; urine, faeces and greywater. The largest nutrient and smallest heavy metal contents are found in the urine, which is easily collected separately using a urine-diverting toilet. The second most nutrient-containing fraction is the faecal matter. This fraction (faeces and toilet paper) has the smallest mass of the three, approximately 60 kg of wet weight per person and year. The nutrients in the urine and faeces have to be recycled to agriculture for society to be sustainable. The faecal matter can either be collected dry or, after a short waterborne transport, be separated from the flushwater in a separator that uses a combination of whirlpool effect, gravity and surface tension. Using this type of separation, between 58% and 85% of the faecal nutrients were separated in the measurements performed here. By recycling the urine and the faecal nutrients, much energy can be saved as the load on the wastewater treatment plant decreases and as mineral fertilisers are replaced in agriculture. To avoid transmission of diseases, the faecal matter has to be sanitised before recycling. If the faecal matter is collected dry, it is possible to perform the sanitation by thermal composting, preferably together with household biodegradable waste. A calculation method for determination of the safety margins for sanitation was developed. In a pilot-scale study, the safety margin for thermal composting of faeces and food waste, with old compost as an amendment, was approximately 37 times total inactivation of Enteroviruses, the most thermotolerant organism evaluated. Another sanitation method investigated was chemical disinfection using urea or peracetic acid. At a dosage between 0.5% and 1.0%, the highly reactive peracetic acid inactivated all investigated organisms within 12 hours of treatment. The high dry matter content (10% DM) meant that high dosages were needed. Lower dry matter content would decrease the dosage required for proper sanitation. A very promising treatment was the addition of urea. Addition of 30 g ureanitrogen per kg of wet weight faecal matter resulted in total inactivation of the monitored organisms, E. coli, Salmonella spp, Enterococcus spp, Salmonella typhimurium 28B phage and Ascaris suum eggs, within 50 days of treatment at 20°C. The spore-forming bacteria Clostridium spp in its dormant state was resistant to this treatment. As the urea has to be degraded to ammonia before it functions as a disinfectant, there is some delay in this treatment. Therefore, urea addition followed by 2 months storage is the preferred treatment for disinfection of separated faecal matter. As additional effects, urea increases the fertiliser value of the treated material and there is no risk of microbial regrowth. Changing to urine-diversion combined with faecal separation and disinfection by urea seems to be an interesting way to decrease the resource usage and possibly improve the hygienic standard of wastewater systems.
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Important amounts of plant nutrients excreted by humans are found in human urine. This provides the motivation for separating urine and recycling it, as fertiliser, back to agricultural land for food or fodder production. There are some housing estates in Sweden, both blocks of flats and separate houses, in which urine-separating toilets have been installed. The urine is stored in covered basins and spread on agricultural land. The objective of the present study was to evaluate the influence of application rate, application techniques and time on NH3 emissions after application of source-separated human urine. Human urine was spread at different application rates (10, 20 and 60 Mg ha–1) before sowing (year 1 to 3) and when the barley crop was 20-30 cm high (year 2). Urine was spread with a plot spreader using two band-application techniques (with bands 0.25 m apart): trailing hoses and trailing shoes. In spring, band-spread urine with trailing hoses was incorporated with a harrow four hours after application. The four (year 1 and 3) or six (year 2) treatments were organised into a randomised block design with three replicates. An equilibrium concentration method was used for measuring ammonia emissions directly after application. After spring application with trailing hoses and harrowing after four hours, the nitrogen [N] loss as ammonia [NH3], average over 3 years, was 5% of the applied N, irrespective of the application rate. The largest loss (10% of the applied N) was measured after application of 60 t of urine per hectare in spring. Hardly any NH3 loss occurred after incorporation with a harrow, with the exception of the highest application rate. Loss of NH3 was very low, close to 1% of the applied N, when the urine was incorporated directly into the soil in spring by band application with trailing shoes. Virtually no emissions were detected when the urine was applied to the growing crop, neither by trailing hoses nor by trailing shoes. This study shows that it is possible to apply human urine on bare soil or in growing barley crop with very low losses of N as NH3. Together with careful handling and the use of covered storage, nutrients in human urine could be recycled from households to agricultural land with low NH3 emissions.
Article
Stored human urine had pH values of 8.9 and was composed of eight main ionic species (> 0.1 meq L–1), the cations Na, K, NH4, Ca and the anions, Cl, SO4, PO4 and HCO3. Nitrogen was mainly (> 90%) present as ammoniacal N, with ammonium bicarbonate being the dominant compound. Urea and urate decomposed during storage. Heavy metal concentrations in urine samples were low compared with other organic fertilizers, but copper, mercury, nickel and zinc were 10–500 times higher in urine than in precipitation and surface waters. In a pot experiment with15N labelled human urine, higher gaseous losses and lower crop uptake (barley) of urine N than of labelled ammonium nitrate were found. Phosphorus present in urine was utilized at a higher rate than soluble phosphate, showing that urine P is at least as available to crops as soluble P fertilizers.
Urine and compost efficiency applied to let- 359 Waste Management Strategies r360 Sustainable Organic Waste Management for Enviromental Protection and Food Safety tuce under greenhouse conditions in Temixco
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Palmquist, H., Jönsson, H. 2004. Urine, faeces, greywater, greywater and biodegradable solid waste as potential fertilisers. In: Ecosan – closing the loop. Proceedings of the 2nd International Symposium on Ecological Sanitation, Incorporating the 1st IWA Specialist Group Conference on Sustainable Sanitation, 7th-11th April, Lübeck, Germany, pp. 587-594
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Schönning, C., Stenström, T. A. 2004. Guidelines for the safe use of urine and faeces in ecological sanitation systems. EcoSanRes report 2004-1. Available at www.ecosanres.org Simons, J., Clemens, J. 2004. The use of separated human urine as mineral fertiliser. In: Ecosan – Closing the loop. Proceedings of the 2 nd International symposium on ecological sanitation, incorporating the 1 st IWA specialist group conference on sustainable sanitation, 7 th -11 th April 2003, Lübeck, Germany. pp 595-600.