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

1 INTRODUCTION
In regions of the world, where low availability of water causes significant problems, the
sustainable use of water resources is a fundamental task. Due to increasing water demand,
global structural shifts, and climate change, investments particularly in water saving
techniques and improved water management systems are vital developments in those areas.
A solution to these challenges is offered by greywater reuse, with multiple use of water in the
household (fbr, 2011). Wastewater treatment techniques, which result in an enhanced
removal of a wide range of contaminants, enable the implementation of such an approach. In
particular, the industry works actively on water reuse projects, not only for economic reasons,
but also from the perspective of an environmental responsibility (Van der Bruggen, 2010).
Greywater is a part of domestic wastewater which is produced during personal hygiene
routines such as showering, bathing or hand-washing. In addition, washing machine,
dishwasher and kitchen sink water also generates greywater. It is faecal free, and low
polluted wastewater (DIN EN 12056-1, 2000). Every single household within a given region,
and with an equal cultural background, produces similar amounts of greywater with a similar
quality every day, regardless of weather conditions.
In order to “lead by example”, the Deutsche Gesellschaft für Internationale
Zusammenarbeit (GIZ) GmbH installed a greywater treatment system within the research
project SANIRESCH in its headquarters located in Eschborn, Germany (Winker & Saadoun,
2011). The aim is to showcase the potential of such systems for urban areas in both,
developed and developing countries. The system is based on the technology of membrane
bioreactor (MBR), a method which provides a very good cleaning capacity and effective
removal of contaminants (Mallevialle et al., 1996), developed by company HUBER SE. After
MBR treatment, the purified water fulfils the regulations of the EU directive 2006/7/EG for
bathing water quality. The water is then called process water. It can be used optimally for
irrigation, toilet flushing or laundry.
This technology firstly reduces the water consumption and secondly substitutes drinking
water in applications where drinking water quality is not required. Reuse of treated greywater
as process water contributes to the protection of the water resources and exerts a positive
influence on the water balance as well as on the environment. Additionally, drinking water
demand is reduced by greywater recycling, and the negative effects of the drinking water
extraction and distribution processes (e.g. energy and chemical requirement, drop in the
groundwater level, consumption peaks) can be minimised as well. Finally, the production of
wastewater and discharge into the sewer system is reduced and consequently also the water
pollution (fbr, 2005).
An important aspect within the research project and also for GIZ is to investigate the
worldwide transferability of such a decentralised wastewater substream treatment. The
pivotal question in this context is whether membrane bioreactor treatment of greywater is a
meaningful and feasible application in emerging and developing countries, as they are often
affected by water shortage and problems of freshwater supply and discharge.
Generally, this study tried to find answers on the following questions that refer to technical
issues of membrane bioreactor technology:
- Is the membrane bioreactor technology a feasible system to recycle greywater?
- What is the advantage of greywater treatment via MBR technology?
- What is the quality like of MBR treated purified greywater?
Furthermore an assessment of the treatment system was made, in order to see the
differences between the utilisation of the technology in a research project and in a serial
application. For this purpose, economical parameters were roughly estimated in order to get
an insight into the costs. This task triggered the following queries:
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