Newsletter and Technical Publications
<International Source Book On Environmentally Sound Technologies
for Wastewater and Stormwater Management>
Section 2
Environmentally Sound Technologies and Practices
1. Overview of the Sound Technologies and
Practices section
Technologies which are environmentally sound are technologies which help
protect the quality of the environment. It may be argued that technologies used
to manage wastewater and stormwater are inherently environmental technologies,
because without these technologies the pollutants in wastewater and stormwater
will negatively affect the environment (Section 1). Some of these technologies
may utilise less energy than others, produce less air pollution or hazardous
sludge, or more suited to wastewater and sludge reuse. Hence some of these
technologies are more sustainable. The application of a technology is dependent
on local physical factors of land availability, its topography, climate, soil,
availability of energy and existing land uses. Sound technology practice is
therefore dependent on being able to fit the technology to the local conditions.
Sound practice is also dependent on the context of the local community where
the technology is to be applied. Long term sustainability is a function of
community resources (funds, skills) to afford the technology and its willingness
to pay for the technology and its operation. Sound practices are therefore
practices which fit into the environmental, economic, social, cultural and
institutional setting of the community.
In this Section wastewater and stormwater characteristics are described to
set the context for technologies that need to be used to manage the pollutants
they contain. The description is also meant to indicate the resources that are
contained in human excreta, and therefore its potential for reuse. Technologies
for collection, treatment, reuse and disposal are then described, so that
options for the different local environmental, economic and social contexts
described above can be evaluated. The description is not meant to be exhaustive,
but to enable the scientific basis of the technologies to be understood. The
relationship between processes in engineered systems and natural purification
processes is also presented, so that simple engineered systems that are more
akin to natural systems can be appreciated. Sludge is produced from treatment
systems, and a section is devoted to its characteristics, treatment, reuse and
disposal. Finally sound technology practices are reviewed in the context of
environmental, economic and social conditions of a community.
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