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At
the global level there are several driving forces working in favour of the
promotion of ecological sanitation. There is growing awareness of the need
to develop long-term sustainability in the use of natural resources.
Freshwater resources are scarce in many ports of the world and even where
they are abundant, conventional sanitation systems (if there are any at
all) ranging from pit latrines to advanced sewage treatment plants are
inadequate and are degrading surface and groundwater quality and
ecosystems. The loss of biodiversity is also a threat to our own survival,
because of the loss of ecosystem services.
The
development of ecological sanitation in the industrial world has had two
different approaches. One focuses on water and it use and reuse while the
other has a more systemic approach, focusing on use and reuse of all
associated resources (water, energy, nutrients, etc.). These systems are
neither cheaper nor less technically sophisticated than conventional
sanitation systems. Although many of the costly high-tech solutions are
not transferable to developing countries, certain aspects can be learned
and transferred. There is a need for innovative and alternative approaches
to conventional sanitation. Wastes discharged have negative impacts on the
environment and people's health. Recycling may prove more beneficial.
Phase
1 of Sanres has mainly been active in supporting and developing low-cost,
dry sanitation systems that are appropriate for people with limited
financial and technical resources. Developments in the North may prove
useful in the further pursuit of ecological sanitation. There is much
experience built up in both the North and South and even if technical
solutions may vary, knowledge transfer is invaluable for spreading the
concept of ecological sanitation as an appropriate and trustworthy
alternative to conventional sanitary systems. Ecological sanitation is not
only a solution for the poorest of poor, but also an alternative anywhere
a sanitary system is required. This Sida-financed initiative will
significantly contribute to a wider application of ecological sanitation.
Much
of the R&D in regard to the opportunities to introduce ecological
sanitation in developing countries has been summarised in the Sanres
publication Ecological
Sanitation. This 1998, Sida publication (ISBN 91 586 76 12 0) is a
solid review of the state of the art in developing countries. Examples
from the Sanres pilot projects are given. Many technical solutions are
presented and the experimentation has been documented. They can work well
and achieve an acceptable level of pathogen destruction. Knowledge has
been gained during Phase 1 to support recommendations for use of these
systems to make them safe. The problems associated with the
flush-and-discharge approaches have been reviewed. However, in the Third
World, sewage is nearly always discharged into the environment-at-large
without treatment. Globally, sewage discharges from centralized,
water-borne collection systems are a major component of water pollution,
contributing to the nutrient overload of water bodies, toxic algae blooms,
e.g. red tides, and adversely influencing tourism in some coastal areas.
Although such systems are acceptable to the vast majority of people, they
are not simple; institutional capability is lacking; technical skills not
currently available in many Third World cities; and the systems are not
sustainable, imposing high recurrent costs.
The
so-called double-vault urine diverting dry toilet appears currently to be
the favoured technical solution to ecological sanitation installations,
although other options do exist and are being used. The urine diverting
option, in addition to being the preferred collector, also has proven to
be easily adaptable to diverse cultural needs.
Many
merits of the ecological sanitation installations are documented both for
rural and urban areas. However, additional R&D is clearly necessary to
make a convincing case for ecological sanitation as an alternative to
water-based sanitation, placing it in a larger perspective of the
ecological cycle and thereby closing the loop. |
