Agricultural aspects of ecological sanitation

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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Desertification / soil erosion
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 http//pubs.usgs.gov/
Sourcehttp//users.aber.ac.uk/
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)
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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Introduction to ecosan
Trend of fertilizer consumption
(Saskatchewan Interactive, 2002)
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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?
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For the consumer
in out
An adults body is barely growing.
Most minerals we take up with our food will be
found later in our excreta !
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The nutrient content of faeces and urine
Fertilising action Urine - readily available on
application Faeces - nutrients released
slowly
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The nutrient content of faeces and urine
Nutrients in urine N Urea P
Phosphate K Ions
Fuente Wolfgast, 1993
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Nutrient excretion
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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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
gt
Source Esrey et al., 1998
gt
gt
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 for200
m2 to 400 m2 agricultural production area,
depending on soil and plant type
gt
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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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phosphate
Introduction to ecosan
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 2003-07, 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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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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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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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 plants needs in nutrients (no
  over-fertilization, ground water protection)

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Reuse
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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
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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
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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
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
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The fertilising effect of urine
Results of a field trial using human urine as a
fertiliser for leeks (Sweden)
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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)
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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
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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
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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
Urban agriculture
Composting with organic waste
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Agricultural use wastewater
Nutrient recycling - epuvalisation (Senegal)
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Fishfarming with wastewater from ducks, poultry
or pigs husbandry (Asia)
Source Nils de Pauw
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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.

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Survival of pathogens on crops and vegetables
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Survival of pathogens in the soil
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Hygienic quality standards for reuse (WHO 1989)
for wastewater
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Hygienic aspects
Personal hygiene and handling care measures
Gloves and shoes for work when handling ecosan
products
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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)

• 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

Urine

• Separate treatment of industrial wastes /
  wastewater
• Monitoring of dangerous substances

Industrial wastes

• Awareness raising and capacity building
• Implementation of neighbourhood based services
• Avoid misuse

Maintenance of ecosan systems
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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/(haa) Maximum P (Phosphorus) 25 kg/(haa)
Extension area for urine and faeces application
from one adult person
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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

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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

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.... and ensuring health protection
One person can provide enough nutrients for200
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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For health protection hardware is not enough
Esrey et al., 1991
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The multiple barrier concept
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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

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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
  (gt1 million)
• Helminths, protozoa viruses - low dose
  required (lt 100)
• Note 1g of faeces can contain millions of
  organisms.

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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.

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The multiple barrier concept
Proper treatment and management
First Barrier
Second Barrier
Source Wagner and Lanois, 1958
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Veranstaltung, Ort, Datum
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Sanitising urine
Time and Temperature
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Sanitising faeces
Temperature pH Ammonia Dryness Solar
radiation Competition Nutrients Oxygen
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DestructionofpathogensEffect oftime andtemp.
The safety zone
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Weigh the risks and benefits
In some cases 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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