Environmental Engineering Reference
In-Depth Information
Table 3 Examples for existing wastewater reuse schemes using agroecological elements
Country
Practice
Source
Egypt
Engineered wetlands for water treatment (at 10 % of
the cost of traditional, chemical-intensive wastewa-
ter treatment systems),
fish farming and agriculture
El-Gamal (
2013
)
India
Crops that tolerate higher contamination levels (e.g.
fodder grass) grown in proximity to the city with
more sensitive crops (e.g. rice, vegetables) cultivated
further downstream where the contamination levels
of wastewater are lower
Amerasinghe et al. (
2009
),
Bradford et al. (
2003
)
India
Cultivation of cauliflower and beet root in the same
wastewater irrigated plots
Hunshal et al. (
1997
)
India
Beetles as bio-control agents against weeds
Bradford et al. (
2002
)
India
The East Kolkata wetlands are one of the world
'
s
largest integrated systems of wastewater treatment,
aquaculture and irrigated agriculture
Fureddy and Ghosh
(
1984
), Ghosh (
2005
)
Peru
Small treatment ponds for aquaculture (
sh pro-
duction). Ef
uent is then used for agricultural
irrigation
Moscoso Cavallini (
2013
)
Sweden
Short-rotation willow coppice for low-cost treat-
ment. Biomass used for combined heat and power
generation
Dimitriou and Aronsson
(
2005
)
Therefore, rather than doing nothing about a situation in which large volumes of
wastewater are disposed of untreated into the environment, it makes more sense to
introduce a management approach loop based on agroecological principles. With
regards to the need to adapt each system to its speci
c local context and for a
participatory learning and development process is not meant as a
fixed model but
rather as a basis for discussion (Fig.
4
).
5 Conclusions
The huge demographic and social changes that will happen in the next decades will
greatly impact society. Urbanization, as one of the most critical changes, in fact the
most relevant in the next 50 years, will impact signi
cantly on wastewater gener-
ation and the need for increased food production. So far, most of the world
s
wastewater enters the environment untreated. This does not only constitute risks
that are dif
'
cult to manage, but also an enormous waste of resources. Wastewater
irrigation offers the possibility to link environmental and health protection with
food and energy production and income creation. New approaches offer great
promise to engage many informal workers in the creation of worthwhile enterprises.
So far, there has been a discrepancy between a focus on expensive technical
solutions to wastewater treatment from of
cial bodies on the one hand and millions
of farmers using wastewater semi-legally or illegally on their
fields on the other
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