Agriculture Reference
In-Depth Information
technology such as a Biostar, which is a biological wastewater treatment,
designed by the Instituto Mexicano de Tecnología del Agua (IMTA) in Cu-
ernavaca, México, or an Rotating Biological Contactor (RBC). However,
these will need a (small) sewage network and perhaps pumps to collect
and transport the wastewater besides the need for skilled operators as well
as an energy source to function and perform adequately.
In a more centralized scenario the existing sewage system and waste-
water treatment plant can be extended. However, the multiple unplanned
settlements not only make it diffi cult to extend the existing sewage system
in order to serve all households (as the capacity of the wastewater treatment
plants might need to be increased and a new sewage network will need to
be constructed amidst existing buildings and chinampas, thereby severely
limiting the design possibilities), but there are also multiple buildings con-
structed over the existing sewage system which makes rehabilitation and ex-
tension works impossible to perform without demolishing and reconstruct-
ing the buildings. Hence the expansion of the centralized system might be
more diffi cult to realize than the construction of decentralized measures. On
the other hand, the centralized system is a technology preferred by the lo-
cal inhabitants, meaning that the implementation of decentralized sanitation
options might be more diffi cult due to the lower social acceptance. This,
however, still needs to be evaluated. An example of how the implementation
of a decentralized sanitation option such as EcoSan can result in resource
recovery and water conservation is presented as follows:
(1) Description of Current Situation
The sanitation situation in the peri-urban areas of Xochimilco differs per
location. A number of houses, generally located near the urban areas and
that are connected to the water supply system or store water in tanks, make
use of flush toilets. These discharge their water into the canals or septic
tanks, which are often poorly constructed or just a hole in the ground.
Other, more remote, households make use of pour flush toilets or pit la-
trines that are often poorly constructed or defecate and urinate directly in
the environment. Gastronomical and skin problems and diarrheal diseases
are common in these areas [32].
