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

3.6 INVESTIGATION OF INTERNATIONAL TRANSFERABILITY OF GREYWATER
TREATMENT SYSTEMS WITH MBR TECHNOLOGY
3.6.1 BASIC PRINCIPLES
The prevailing centralised wastewater system in Germany is very well adapted for our
local conditions, but the wastewater transport and treatment facilities are not optimally
transferable to many other regions of the world. Although it is a powerful technology, the
international transfer is often not meaningful because of local climatic, economic and cultural
conditions. Reasons for this include a low flexibility with respect to changes in capacity, for
example in a rapidly growing city or in inconveniently located settlement structures. There is
no possibility to reuse purified water close to the village (e.g. in agriculture or industry)
(Herbst, 2008).
Therefore, urban planners are investigating decentralised systems where the wastewater
is treated close to the location where it is generated. Even for urban areas prone to natural
hazards this may even be an appropriate option (Corcoran et al., 2010)
The unequal dispersal of wastewater ingredients in the sub-streams of domestic
wastewater is regarded as a reason for considering a system change (Lange & Otterpohl,
2000), particularly regions with lack of water can benefit from recycling orientated “closing
the loop” technologies.
The practice to use treated greywater as process water contributes to the protection of the
environment and water resources. Greywater treatment plants reduce the demand for
drinking water that is used for purposes other than cooking, drinking or personal hygiene and
therefore exert a positive influence on the water balance. Thus, the negative effects of the
drinking water extraction and distribution processes are reduced. Additionally, greywater
recycling reduces the volume of produced wastewater and consequently, the water pollution
risk as well (fbr, 2005).
The separate collection, treatment and reuse of greywater is useful, if the water balance of
greywater production and process water demand is almost equal within a building. In new
constructed or renovated buildings, it is easy to provide additional piping systems for
installation to collect greywater separately from blackwater and distribute the treated
greywater in the building again (HUBER SE, 2011c).
3.6.2 RESULTS OF UTILITY ANALYSIS OF INTERNATIONAL TRANSFERABILITY OF
GREYWATER TREATMENT VIA MEMBRANE BIOREACTOR TECHNOLOGY -
MATRIX OF UTILITY ANALYSIS
In section 2.4 the method of investigation, evaluation, rating and weighting of international
transferability of MBR treatment by utility analysis is explained and described. The complete
matrix of utility analysis is presented in Table 24 together with three examples of evaluated
projects. Especially the compilation of main groups and its sub issues within the utility
analysis was a development process, same as weighting of sub categories. It is based on
literature study, discussion with experts and in the end the final adaptation of rating was done
by the investigation of existing projects with a good data basis.
53