Reclaim Water
RECLAIM WATER - Water reclamation technologies for safe
artificial groundwater recharge
In many regions of the world, high quality freshwater resources
are becoming scarce due to growing population and increasing water demand.
Consequences are the use of lower quality water and conflicts about the right
for exploiting the water sources. Solutions, like alternative water resources,
are urgently needed to work against these problems, yet they must be
sustainable, economical and safe. One of the most obvious and promising option
in integrated water management seems to be the utilisation of reclaimed
municipal wastewater. These days purified wastewater is still discharged into
the rivers, but soon it might be possible to use it for artificial groundwater
recharge. For an indirect reuse as potable water it has to meet higher
requirements though.
This topic is investigated in the Reclaim Water project, an international research project with a consortium of 16 institutions from 13 different nations, combined in 8 work packages (WP) and supported by the European Commission under the Sixth Framework Programme.
The aim of this project is to provide efficient technologies to
monitor and minimise the content of pathogens and chemical contaminants in
reclaimed wastewater used for groundwater recharge.
Within WP1 - ”Assessment and development of water reclamation
technology” Eawag operates a membrane plant (pilot scale) to investigate the
degradation of micropollutants. The micropollutants are retained by
nanofiltration and recycled to the membrane bioreactor (see scheme above). As a
result of the longer retention time in the system we expect a higher degradation
of the micropollutants. A device for ozonation can be installed additionally.
Eawag investigates the following main tasks:
- How much biological micropollutant degradation can be achieved at the higher concentrations reached with nanofiltration?
- Is a partial ozonation required in the retentate recycling loop?
- Is a high retention of micropollutants feasible without high retentate discarding (>10%) being necessary due to salt retention?
- Is a membrane reactor combined with nanofiltration a competitive solution compared to ozonation or activated carbon filtration?
Furthermore the degradation capability of a decentralised single house wastewater treatment plant (membrane reactor) is investigated by spiking micropollutants. It is of particular interest to figure out if the microorganisms need time for adapting to compounds not regularly present in the local sewage or if there can be found a high degradation right from the beginning.