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< prev - next > Water and sanitation Sanitation KnO 100408_Ecological Sanitation (Printable PDF)
ECOLOGICAL
SANITATION
A CONCEPT
Introduction
Ecological sanitation (ecosan) works on the principle that human excrement is not a waste
product but contains the nutrients required to fertilise land and that it should be used for this
purpose. The ecological sanitation cycle begins with containment, where excreta is held in the
sanitation installation. The waste is then sanitised through one or several processes which
cause pathogen die off, the resultant safe soil conditioner (from faeces) and fertiliser (from
urine) is then recycled and used to assist crop production. Figure 1 shows these processes
alongside the harvesting, production and consumption of food that keeps the nutrients within
the ecological cycle.
Safe and nutritious
food
Transport
Storage
Processing
People
Excreta
Pathogen
destruction
Harvest crop
Plant
Safe fertiliser and
soil conditioner
Figure 1: The principle of ecological sanitation is to return the valuable nutrients from urine and faeces
back to the environment and avoid the pollution often caused by conventional sewerage whilst
contributing to the food production. [Adapted from: Esrey and Andersson, 2001]
A wide variety of ecosan toilets exist, the
complexity of which vary significantly as a
result of options being explored in both
developed and developing countries. This
technical brief will briefly describe the main
categories of ecosan toilet, the reasons to
adopt ecosan options and some of the
concerns practitioners have about their use.
Figure 2: Nutrient availability for plant growth
[Source: Smet and Sugden, 2006]
Research indicates that human waste from
one person can supply nearly enough
nutrients to produce 250 kg of cereals
annually (figure 2). The majority of the
nutrients are contained within the urine
component, and the faeces contain the most
pathogens (although when treated correctly it
becomes a good soil conditioner).
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