Human Excreta
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Transcript of Human Excreta
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Excreta and Household
Wastewaters - Introduction
Margaret Katusiime Semakula
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Household Human Wastes and
Wastewaters
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Excreta and Graywater Definitions & Properties
Excreta: Human feces and urineManaged in different ways:Direct disposal on land or in water
Direct use as fertilizer, soil conditioner and for aquaculture
Pre-treatment prior to use
Dilution with water to convey (sewage) for disposal or use
Direct use of untreated (raw) sewage
Treatment and discharge to land or water
Treatment and reuse (agriculture, aquaculture, horticulture,
industrial and civil useGraywater: Other wastewater from human activity
Not directly from human fecs and urine
Wastewater from washing, bathing, etc
Contains human wastes and exudates
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Managing Human Excreta - Options
Dry Collection: Open defecation
Collect in a container
e.g., chamber pot
Discharge to theenvironment w/ or w/o Rx
Latrines several kinds
Treat or dispose of or both
Separate feces and urine; Then, treat/store, use,
dispose to the
environment
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Managing Human Excreta - Options
Semi-wet (or semi-dry)
Use some water
Pour-flush toilets and other low water usesystems
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Managing Human Excreta - Options
Wet Systems
On-site Septic Systems
Other On-site systems
Soak pits
Sewerage
Sewage treatment systems
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Human Excreta Resource or Risk?
Nitrogen (N) 4.5
Phosphorous (P) 0.6
Potassium 1.0Organic matter
(as BOD)
35
Human excreta as a potential resource
Contains nutrients (N, P, K, and organicmatter)
Nutrients and organic matter are:
Detrimental in water, esp. surface water
Eutrophication, anoxia, fish kills Beneficial on land
Fertilizer, soil conditioner, land stabilizer
Widely used as a fertilizer and soil
amendment in both developed and developing
countries
Potential for excreta misuse and
environmental pollution is great without proper
attention to management plans and human
behavior considerations
Annual Amounts/Person, Kg
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Nutrient Content of Human Excreta
Rich source of inorganic plant nutrients: N, P K and organic matter
Daily human excretion: ~30 g of C (90 g of organic matter), ~ 10-12 g
N, ~ 2 g of P and 3 g of K.
Most organic matter in feces most N and P (70-80 %) in urine. K
equally distributed between urine and feces.
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0
20
Organicskg COD/ (Personyear)
12.3
3.6
14.1
VolumeLiter / (Personyear)
500 l 50 l
source:Otterpohl
0
6
Nutrient contentkg N,P,K / (Personyear)
N
P
K
0.8
5.3
1.0
Composition of Household
Waste and Wastewater
greywater urine faeces
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of no major (or less) hygienic concern/risk
volumetrically the largest portion of wastewater
contains almost no (or less) nutrients (simpler
treatment)
may contain spent washing powders etc.
3. greywater
less hygienically critical (less risk)
contains the largest proportion of nutrients
available to plants
may contain hormones or medical residues
2. urine
hygienically critical (high risk)
consists of organics, nutrients and trace elements
improves soil quality and increase its water
retention capacity
1. feces
characteristicfraction
Characteristics of Human Wastes
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source:Drangert,
1998
Fertilizer Equivalence of Yearly per Capita ExcretedNutrients and Fertiliser Requirements for Producing
250 kg of Cereals
0
1
2
3
4
5
6
N N P P K K
N
utrient(kg)
cerealrequirements
faeces
urine
Fertilizer Potential of Human Excreta
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treatment
utilisation
substances faeces(brownwater)
anaerobic
digestion,
drying,
composting
biogas,
soil
improvement
constructed
wetlands, gardening,
wastewater ponds, biol.
treatment, membrane-
technology
greywater
(shower,
washing, etc.)
irrigation,
groundwater-
recharge or
direct reuse
urine
(yellowwater)
liquid or dry
fertiliser
hygienisation by
storage or
drying
Options for Excreta and Greywater Utilization