1. Agricultural aspects of ecological sanitation
Christine Werner, Patrick Bracken, Florian Klingel
Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH
ecological sanitation programme, Division 44 – environment and infrastructure
Commissioned by:
Water Resources Protection Workshop, 2-6 May, 2005, Selam Hotel, Asmara
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2. Desertification / soil erosion
Increasing land degradation
Important facts
1/3 of the planet surface is covered by arid and semiarid zones Drylands in the Middle East cover 99% of the surface area.
Half the countries on earth lie partly or entirely in arid and semiarid zones.
Many millions of people have nowhere else to go except to live in arid zones
(UNEP, 1992)
Source:
Source:
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3. Key Elements of Biomass
The limiting factors
Energy (Light)
Water (H²O)
Carbon Dioxide (CO2)
Nutrients
Minerals
If one is missing, adding more of another will not help!!
Macro nutrients: Nitrogen (N); Phosphorus (P); Potassium (K); Sulphur (S); Calcium (Ca); Magnesium (Mg)
Micro nutrients: Boron (B) Copper (Cu) Iron (Fe) Chloride (Cl) Manganese (Mn) Molybdenum (Mo) Zinc (Zn)
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4. A simplified natural ecosystem
In a natural ecosystem all minerals are part of a continuously ongoing cycle.
Humus contains not yet mineralised organic matter.
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5. (Saskatchewan Interactive, 2002)
Introduction to ecosan
Trend of fertilizer consumption
(Saskatchewan Interactive, 2002)
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6. A simplified agro-eco ecosystem
In an agricultural ecosystem, minerals and organic matter are exported from the soil when harvesting the products.
What happens to them?
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7. For the consumer in = out An adult‘s body is barely growing.
Most minerals we take up with our food will be found later in our excreta !
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8. The nutrient content of faeces and urine
Fertilising action: Urine - readily available on application
Faeces - nutrients released slowly
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9. Nutrients in Kg for crop production.
The nutrient content of faeces and urine
1,2
0,17
1,0
Potassium
7,5 Kg
(100%)
0,45 Kg
(6 %)
7,0 Kg
(94 %)
Total N + P + K
0,7
0,6
0,19
0,4
Phosphorous
5,6
5,7
0,09
Nitrogen
Required for
230 Kg de cereales
Total
Faeces
(50 l/year)
Urine
(500 l/year)
Nutrients in Kg for crop production.
Nutrient
Fuente: Wolfgast, 1993
Nutrients in urine
N Urea
P Phosphate
K Ions
Plantas verdes con follaje y no leguminosas Nitrogen
Plantas flores y frutos Phosphorous
Verduras de raíz comestible Potassium
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10. Nutrient excretion
0.4
0.1
0.3
Faeces
1.0
2.2
Urine
1.4
2.5
Uganda, total
0.2
1.2
3.0
1.6
0.5
3.4
South Africa, total
1.1
2.3
1.5
2.7
India, total
0.9
1.9
2.1
Haiti, total
1.3
3.5
1.8
0.6
4.0
China, total
Potassium
kg/cap, yr
Phosphorus
Nitrogen
Country
The estimation of nutrients excretion per capita vary from country to country and even within the same region, according to food habits of people and the food itself
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11. Nutrients ecosan potential / example of India
An adult excretes per year:
~ 4.55 kg N
~ 0.58 kg P (= 1.33 kg P2O5)
~ 1.27 kg K (1.53 kg K K2O)
A family of 4 adults can produce the equivalent of around 30 kg NPK per year
=>
Source: Esrey et al., 1998
=>
=>
No need to buy chemical fertilisers that are more and more expensive for farmers since fossil resources are diminishing
One person can provide enough nutrients for: 200 m2 to 400 m2 agricultural production area, depending on soil and plant type
=>
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12. household nutrient flow* of about:
Value of organic household waste
Organic (kitchen) waste forms a valuable part of the overall
household nutrient flow* of about:
N: ~ 8%
P: ~ 35%
K: ~ 25%
*1571 Analysis of the „Bundesgütegemeinschaft Kompost e.V.“ in 1996
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13. source: US Geological survey, 2003
Introduction to ecosan
phosphate
source: US Geological survey, 2003
World demand for phosphate fertilizers continues to expand in relation to increased world population and food requirements.
For the period , world phosphate consumption is forecasted to increase by 2.6% annually.
Within about 60 years, all reserved phosphate are expected to be mined.
Future conflicts on the access to phosphate are likely, due to the limited reserves and the concentration of significant minable resources in a very small number of countries.
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14. Recovery and reuse is necessary!!
Minerals are very important for a successful agriculture. ?
Fosile
Thinking sustainable means thinking in the generation cycle.
Organic
It doesn't matter what we do today.
Our grandsons and grand-daughters will have to use fertilizers from human resources (urine and faeces) anyway.
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15. Management of resources and quality
Collection:
Product quality/ concentration
Strict separation of all non organic industrial wastes and waste water (toxics and heavy metals)
Awareness, support services, discharge control at household-level !
Out = In
Treatment:
On Site / Off Site
Minimisation of waste and waste water
Guarantee for customer oriented product quality (sampling and control)
Maintenance of value
Transport:
Distances from producer to fields (energy balance)
Concentration / purity of the product (costs)
Marketing:
Acceptance by customer (informed choice)
Costs/benefit (market price)
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16. Reuse
Bio waste, human faeces and urine can be re-used in agriculture and gardening under the following conditions:
Proper pre-treatment (storage, drying, composting, anaerobic fermentation, heating, filtration, irradiation with UV etc.)
Suitable „handling“ (observing all safety measures)
Depending on pre-treatment, the re-use should be limited to specific vegetables and field crops during specific vegetation periods
Regular sampling and hygiene control
Relation to the plant‘s needs in nutrients (no over-fertilization, ground water protection)
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17. Reuse
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18. Benefits of nutrients reuse: soil fertility
Restoration of soil fertility: by reusing nutrients the soil is humus-rich and makes the difference in crops production
faeces & urine
urine
none
Source: Vinnerås, 2003
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19. Benefits of nutrients reuse: soil fertility
Spinach: Left - local soil Right - compost
Green peppers: Left - excreta compost Mid - 1/2 compost, 1/2 soil Right - soil
Lettuce: Left - local soil Right - excreta compost
Source: Peter Morgan, 2004
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20. Benefits of nutrients reuse: soil fertility
Source: CREPA, 2004
Spinach: Left - local soil Right - urine (1 / 3)
Sorghum:
To : nothing
T1 : with P and K
T2 - T4 : P and K plus urine
T5 : mineral fertiliser
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Source: Peter Morgan, 2004

21. Benefits of organic reuse: soil quality
Improved soil quality: organic reuse (as compost) enhances the water - holding capacity, ameliorates the soil structure, the buffering capacity and by supporting the soil micro-organisms
Source: Petter Jenssen
After one week without water
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22. The fertilising effect of urine
Results of a field trial using human urine as a fertiliser for leeks (Sweden)
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23. The fertilising effect of urine
Yields (grams fresh weight) in plant trials with urine as a fertiliser to vegetables in
Zimbabwe (Morgan, 2003)
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24. The fertilising effect of excreta compost
Average yields (grams fresh weight) in plant trials comparing growing in poor topsoil only, with growing in a mixture consisting of 50% topsoil and 50% Fossa alterna compost (Morgan, 2003)
Gains are less pronounced on better quality soils
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25. Agricultural use: urine
Urine - How to apply ?
Urine is collected in tanks via pipes, from separating toilets
Urine is virtually sterile - usually contaminated when it contacts faeces
Source: ecosan study in Havana
Treated by storage
Can be dilute for application (1/3)
Fertilising rules apply!!!
Source: SUDEA
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26. Agricultural use: faeces
Techniques enabling the reuse of faeces in agriculture include:
Composting toilets
Dehydrating toilets
Anaerobic digestion with or no organic waste (biogas production)
Direct injection of liquid fertiliser
Dried faeces - „soil amelioration“
Composting with organic waste
Urban agriculture
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27. Agricultural use: wastewater
Nutrient recycling - epuvalisation (Senegal)
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28. Fishfarming with wastewater from ducks, poultry or pigs husbandry (Asia)
Source: Nils de Pauw
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29. Hygienic risks of reuse
Urine - hygienic quality normally very high. Main risk is cross contamination by faeces
Faeces - risks much higher. Both primary and secondary treatment processes recommended (e.g. storage/composting followed by secondary composting
The HIV virus is very fragile and cannot be spread by treated (stored) “human residues” BUT poor water supply and poor sanitation conditions cause so called “opportunistic infections” as: Diarrhoea, Malaria, Cholera, Skin diseases etc.
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30. Survival of pathogens on crops and vegetables
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31. Survival of pathogens in the soil
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32. Hygienic quality standards for reuse (WHO 1989) for wastewater
not relevant
none
Local application to field crop of cat. B, without contact to persons C
no suggested standard
</= 1
worker
Application to field crop (for industrial use, feedstock, trees) B
</= 1000
worker, consumer, public
Application to field crop (used for raw food) A
Faecal coliforms [number / 100 g]
Nematodes [Eggs / kg]
Person / Group exposed
Use
Category
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33. Personal hygiene and handling care measures
Hygienic aspects
Personal hygiene and handling care measures
Gloves and shoes for work when handling ecosan products 33
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Veranstaltung, Ort, Datum

34. Risk minimisation Faeces and faecal sludge:
Pathogen removal in all treatment steps including:
Storage/treatment (weeks - 1 year)
Post treatment drying/composting, etc. (0,5-1 year)
Time period from application till harvest (0,1-0,5 y)
Urine:
Compliance with recommended urine storage times (depending on storage temperature between 6 weeks (25oC) and 6 months (4oC) (pH)
Consideration of hormones and medical residues
Fresh use to trees
Industrial wastes:
Separate treatment of industrial wastes / wastewater
Monitoring of dangerous substances
Maintenance of
ecosan systems:
Awareness raising and capacity building
Implementation of neighbourhood based services
Avoid misuse
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35. Balance of nutrient cycle
In theory, one person can fertilise with his / her own ecosan recyclates an agricultural area, needed to feed him with vegetables, cereals and fruits.
German law for fertilizer use / water shed protection
Maximum N (Nitrate): 150 kg/(ha*a)
Maximum P (Phosphorus): 25 kg/(ha*a)
Extension area for urine and faeces application from one adult person:
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36. Recommendations for reuse
Excreta (urine and faeces):
Excreta should be handled and treated according to hygiene guidelines
Urine and faeces are complete fertilisers of high quality with low levels of contaminants such as heavy metals. The best fertilising effect is achieved if they are used in combination with each other, but not necessarily the same year on the same area
Faeces:
Both organic matter and ash, which are often added to the faeces, increase the buffering capacity and the pH of the soil, especially important on soils with low pH
Organic matter also improves the structure and the water-holding capacity of the soil
Faeces should be applied and mixed into the soil before cultivation starts
the application rate can be based on the current recommendation for the use
of phosphorous-based fertilisers. This gives a low application rate, and the improvement due to the added organic matter is hard to distinguish. However, faeces are often applied at much higher rates, at which the structure and water-holding capacity of the soil are also noticeably improved
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37. Recommendations for reuse
Urine:
Quick-acting nitrogen-rich complete fertiliser. Best used when applied prior to sowing, up until two-thirds of the period between sowing and harvest
Urine can be applied neat or diluted. However, the application rate should always be based on the desired nitrogen application
The recommended application rate and time for chemical nitrogen fertilisers (urea or ammonium if available) best starting point for developing local recommendations on application rate and time for urine. For translating such recommendations to urine, its concentration can be estimated at 3-7 g per litre
If no recommendations can be obtained, a rule of thumb is to apply the urine collected from one person during 24 hours to 1 square m of crop
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38. .... and ensuring health protection
One person can provide enough nutrients for 200 m2 to 400 m2 agricultural production area, depending on soil and plant type.
Reuse often not a problem but:
Multi-barrier concept needed to secure hygienic safety in the reuse of human excreta and domestic wastewater:
Awareness raising and education on hygiene and reuse aspects
Effective treatment (primary treatment followed by secondary treatment if needed - storage, drying, composting, anaerobic digestion, heating, filtration, irradiation with UV etc.)
Suitable „handling“ (with security measures)
Limitation to specific vegetables and field crops, or to specific vegetation periods, depending on pre-treatment
the crops nutrient needs have to be respected (no over-fertilisation)
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39. For health protection hardware is not enough
Esrey et al., 1991
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40. The multiple barrier concept
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41. The pathogens to be stopped
Four groups of Pathogens:
Viruses: a strand of DNA in a protein coat, causing many types of illness
Bacteria: single-cell organism living in and around us. Some of them are helpful and some other cause diseases
Protozoa: large group of one-celled animal
Helminths: parasitic worms - toughest 41
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42. Infective dose of a pathogen (the dose required to create disease in a human host)
Bacteria: - medium to high dose required (>1 million)
Helminths, protozoa & viruses: - low dose required (< 100)
Note: 1g of faeces can contain millions of organisms.
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43. Sanitation and hygiene
Good sanitation prevents excreta from entering the domestic environment and getting into water
Good hygiene prevents the transmission of microbes from the environment into the human body via hands
Adequate excreta disposal and safe hygiene practices together effectively prevent almost all gastro-intestinal infection.
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44. The multiple barrier concept
Water quality
Fingers
Water Quantity
Hand washing
Hand washing
Fluids
New Host
Faeces
Food
Flies
Fields
Proper treatment and management
First Barrier
Second Barrier
Source: Wagner and Lanois, 1958 44
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45. Sanitising urine Time and Temperature
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46. Sanitising faeces Temperature pH Ammonia Dryness Solar radiation
Competition
Nutrients
Oxygen
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47. Destruction of pathogens: Effect of time and temp.
The safety zone
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48. Weigh the risks and benefits
“..the food supplied and the resulting improvement in nutrition may outweigh the potential health risks from this practice.”
DRAFT GUIDELINES FOR THE SAFE USE OF EXCRETA AND GREYWATER
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49. Thanx
For further information: or subscribe to the ecosan-newsletter by sending a mail to : (text of the mail: subscribe ecosan)
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