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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 Workshop with the Water Resources Department, , Asmara
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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: Workshop with the Water Resources Department, , Asmara
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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) Workshop with the Water Resources Department, , Asmara
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A simplified natural ecosystem
In a natural ecosystem all minerals are part of a continuously ongoing cycle. Humus contains not yet mineralised organic matter. Workshop with the Water Resources Department, , Asmara
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(Saskatchewan Interactive, 2002)
Introduction to ecosan Trend of fertilizer consumption (Saskatchewan Interactive, 2002) Workshop with the Water Resources Department, , Asmara
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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? Workshop with the Water Resources Department, , Asmara
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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 ! Workshop with the Water Resources Department, , Asmara
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The nutrient content of faeces and urine
Fertilising action: Urine - readily available on application Faeces - nutrients released slowly Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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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 => Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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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. Workshop with the Water Resources Department, , Asmara
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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. Workshop with the Water Resources Department, , Asmara
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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) Workshop with the Water Resources Department, , Asmara
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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) Workshop with the Water Resources Department, , Asmara
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Reuse Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara Source: Peter Morgan, 2004
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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 Workshop with the Water Resources Department, , Asmara
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The fertilising effect of urine
Results of a field trial using human urine as a fertiliser for leeks (Sweden) Workshop with the Water Resources Department, , Asmara
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The fertilising effect of urine
Yields (grams fresh weight) in plant trials with urine as a fertiliser to vegetables in Zimbabwe (Morgan, 2003) Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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Agricultural use: wastewater
Nutrient recycling - epuvalisation (Senegal) Workshop with the Water Resources Department, , Asmara
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Fishfarming with wastewater from ducks, poultry or pigs husbandry (Asia)
Source: Nils de Pauw Workshop with the Water Resources Department, , Asmara
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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. Workshop with the Water Resources Department, , Asmara
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Survival of pathogens on crops and vegetables
Workshop with the Water Resources Department, , Asmara
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Survival of pathogens in the soil
Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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Personal hygiene and handling care measures
Hygienic aspects Personal hygiene and handling care measures Gloves and shoes for work when handling ecosan products 33 Workshop with the Water Resources Department, , Asmara Veranstaltung, Ort, Datum
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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 Workshop with the Water Resources Department, , Asmara
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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: Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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.... 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) Workshop with the Water Resources Department, , Asmara
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For health protection hardware is not enough
Esrey et al., 1991 Workshop with the Water Resources Department, , Asmara
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The multiple barrier concept
Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara Veranstaltung, Ort, Datum
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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. Workshop with the Water Resources Department, , Asmara
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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. Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara Veranstaltung, Ort, Datum
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Sanitising urine Time and Temperature
Workshop with the Water Resources Department, , Asmara
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Sanitising faeces Temperature pH Ammonia Dryness Solar radiation
Competition Nutrients Oxygen Workshop with the Water Resources Department, , Asmara
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Destruction of pathogens: Effect of time and temp.
The safety zone Workshop with the Water Resources Department, , Asmara
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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 Workshop with the Water Resources Department, , Asmara
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Thanx For further information: or subscribe to the ecosan-newsletter by sending a mail to : (text of the mail: subscribe ecosan) Workshop with the Water Resources Department, , Asmara
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