Infrastructure Models for Ecological Wastewater Management - Restorative Redevelopment of Devastated Ecocultural Landscapes - page 400

of the world population lives in developing countries (Population Reference Bureau
2002). As the world's population continues to grow, it is shifting from rural to urban
areas. Total urban population was projected to be 2.3 billion in 1990 and is projected
to increase to 4.6 billion by 2020, with 93 percent of this growth occurring in less
developed countries.
The shift from rural to urban areas continues to create dense population cen-
ters that lack basic sanitation facilities, representing about 38 percent of the current
world population (Postel 2003). Approximately 40 percent of the world's population
is experiencing water stress (Glieck 1993). Continued exploitation of water reserves
is likely to have detrimental long-term consequences on the availability of fresh
water for human communities and native ecosystems (Kivaisi 2001). As water scar-
city becomes more and more common, reuse of treated wastewater becomes increas-
ingly important.
In the context of the Mesopotamian marshes, Iraq is undergoing a transformation
from a water-rich country to a water-poor country. The construction of dams along
the Tigris and Euphrates Rivers (including the massive Ataturk Dam in Turkey) has
significantly altered the natural hydrology of the marshes, and water diversions for
irrigation are severely limiting the quantity and quality of water available for marsh
restoration. Current estimates surmise that only 15 to 20 percent of the drained
marshes can be restored (Richardson et al. 2005) given the limitations on water avail-
ability now, and the uncertainty of water availability in the future. In a water-scarce
future, wastewater reuse will play an important role in meeting Iraq's water needs.
CREATING SUCCESSFUL WASTEWATER INFRASTRUCTURE
Creating an infrastructure that successfully meets the needs of a society depends on
implementing the “correct” technology. In this context, “correctness” can be defined
as how well the selected technology meets the needs of society. In Iraq, there is
clearly a large, unmet need for wastewater treatment, and as water scarcity becomes
more common, effluent reuse will become a preferred management option. So, if the
need is apparent, and water is scarce, why is technology selection difficult?
The societal “fit” of a technology is critical in technology selection, and is depen-
dent on many factors. The technology needs to be compatible with cultural values
and traditions, but it also has to make sense economically. In most cases, this means
that the wastewater system can be built using locally available materials and is easy
to operate and repair. The system must provide effective treatment, yet be capable of
being locally operated and maintained. Finally, there must be societal support for the
system, which requires that the benefits of the treatment system (in terms of public
health, environmental protection, and economic return) are apparent to the commu-
nity. However, technologies that can be offered as a solution are highly dependent on
the scale of the infrastructure, as discussed in the next section.
THE EFFECT OF SCALE IN WASTEWATER INFRASTRUCTURE
Wastewater infrastructure around the world generally falls into one of three models
(Hallahan and Wallace 2001). These three infrastructure models are categorized by