An innovative greywater treatment system for urban areas ... - SuSanA

for reuse projects. In total 32 countries, which are suffering from lack of water or approaching
water scarcity were assessed by a trimmed-down utility analysis. According to the four rating
criteria: water shortage, water quality, population density and urbanisation rate an appraisal
based on environmental aspects was conducted. Jordan was identified as a predestined
country (with a maximum rating), for the implementation of greywater recycling via MBR plant
technology, due to a correlation of all assessed criteria. Further ideal applications for
international greywater recycling projects are in the Middle East and North Africa region,
especially Oman, Egypt, Libya, and Saudi Arabia can be pointed out. These countries are all
characterised by water shortage and high urbanisation rate in combination with high
population density, which makes MBR technology reasonable. In addition, a main focus can
be on existing or emerging megacities, due to the technology’s potential to improve living
conditions, when implemented within urban planning projects.
This approach, to assess four environmental aspects, can only outline a rough estimation
of global hotspots, due to regional differences. By identification of water scarcity, as an
indicator criterion, a pre selection within the assessment was made. The worldwide view on
all four assessed environmental criteria without pre-selection may show slight changes, but
this was not possible within the limited time of this work. Furthermore, the estimation is
based on a maximum rating of 21 % of 100 % within the utility analysis, which contributes
only one-fifth to the analysis. Therefore, it must be taken into consideration that further
aspects, like economic, socio-cultural and legal criteria, can add a serious weight into
assessment as well.
In general, the identified regions represent appropriate conditions based on environmental
criteria; further aspects like installation of such a technology in large buildings with high water
consumption contribute to making a MBR project even more suitable. The same applies for
economic, legal and socio-cultural conditions, if the circumstances meet the sustainable
criteria according to the utility analysis, the project becomes more viable. Hence, a
consideration of all aspects is always necessary to identify the practicability of membrane
bioreactor technology in a certain application. Worldwide, there are a variety of application
ranges, where a viable reuse application is possible, but it needs to be well-planned, by
taking all background information into account, including economic and sustainable aspects.
To endorse the dissemination of greywater recycling, legal measures are necessary.
Governments are developing policies with incentives and/or permits to stimulate water
recycling in an industrial context. A further step in the right direction would be an adequate
price for drinking and wastewater. Often, the subsidised water price in countries with water
scarcity eliminates the stimulus to install water saving technologies such as greywater
recycling.
At the moment water reuse technologies are often considered as a gadget without benefit
and with the risk of malfunction within a project. To make greywater recycling by membrane
bioreactor technology a popular and widespread technology, further development steps are
necessary. To achieve marketable plants on a serial scale, the dispersal of ready-made
systems which can be offered cheaply, is a step required in the future.
Finally, a general paradigm shift must take place, as today's water and sewage systems
are no longer acceptable in respect to sustainability aspects. In particular, it is not an
exportable solution to emerging and developing countries, where volumes of wastewater are
increasing as well as the scarcity of water. The well-known conventional method with
centralised treatment plants is very cost intensive, due to the expensive sewer systems and
high operation costs of the sewage treatment plants. These systems are hardly affordable in
emerging and low-income economies; hence they should not be promoted as a sanitation
solution in such contexts. Additionally, the conventional wastewater treatment methods are
only disposal oriented and the potential of recycling and reuse is not taken into consideration.
Based on a holistic approach, by “closing the loop” a recirculation of water within the building
without any wastewater production is a conceivable future.
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