Agriculture Reference
In-Depth Information
on-site scale [4-8]. However, stakeholders may prefer centralized solu-
tions because of the convenience of a centralized system.
The introduction of decentralized technologies allows for the develop-
ment of new opportunities that enable the recovery and reuse of resources
in the form of water, nutrients and energy. This resource-oriented manage-
ment of water, nutrients and energy requires a sustainable system aimed at
low resource use and high recovery and reuse rates.
Instead of designing each sector separately, which has been tradition-
ally done, this article proposes and discusses a concept that combines the
in- and outfl ows of the different sectors, reusing water and other liberated
resources where possible, which is illustrated in Figure 1. “Joints” for pos-
sible integration of these sectors are: water reuse, nutrient recycling and
energy recovery. In the decentralized concept all wastewater in a region is
seen as a separate water, nutrient and energy source, and is evaluated for
its suitability as a water source for a specifi c use, such as agriculture, non-
potable domestic purposes or forest irrigation. With letting the fi nal users
determine the quantitative and qualitative water requirements needed for
a specifi c purpose such as agriculture, industry or (nonpotable) household
activities, the user or purpose of the wastewater determines the quality to
which the wastewater is improved, which is the opposite of the conven-
tional water chain where governmental legislation or permits dictate the
treatment level. This reverse water chain [9-11], results in a new and novel
view of waste and wastewater treatment and water sourcing where legisla-
tion should allow for tailor-made solutions. This may also reduce costs as
not all waste and wastewater need to be treated up to high standards, since
a part can also be used for purposes only requiring lower standards.
This paper shows and demonstrates examples of different types of sus-
tainable water technologies that can be implemented in the peri-urban ar-
eas of Mexico City. An innovative participatory planning method using a
scenario building methodology at project level was applied. This method
has allowed for a meaningful and intensive involvement of a variety of key
stakeholders in the planning process. It also helped to identify the oppor-
tunities and limitations of resource oriented water technologies within an
urban planning context highlighting the confl ict between environmental
conservation and urbanization.
