Abstract
M embrane-based water desalination processes and hybrid technologies are
often considered as a technologically and economically viable alternative
for desalination of geothermal waters. This has been confirmed by the
results of pilot studies concerning the UF-RO desalination of geothermal
waters extracted from various geological structures in Poland. The
assessment of the feasibility of implementing the water desalination
process analysed on an industrial scale is largely dependent on the method
and possibility of disposing or utilising the concentrate. The analyses
conducted in this respect have demonstrated that it is possible to use the
solution obtained as a balneological product owing to its elevated
metasilicic acid, fluorides and iodides ions content. Due to environmental
considerations, injecting the concentrate back into the formation is the
preferable solution. The energy efficiency and economic analysis conducted
demonstrated that the cost effectiveness of implementing the UF-RO process
in a geothermal system on an industrial scale largely depends on the
factors related to its operation, including without limitation the amount
of geothermal water extracted, water salinity, the absorption parameters
of the wells used to inject water back into the formation, the scale of
problems related to the disposal of cooled water, local demand for
drinking and household water, etc. The decrease in the pressure required
to inject water into the formation as well as the reduction in the stream
of the water injected are among the key cost-effectiveness factors.
Ensuring favourable desalinated water sale terms (price/quantity) is also
a very important consideration owing to the electrical power required to
conduct the UF-RO process.
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