Impact of speciation on fluoride, arsenic and magnesium retention by nanofiltration/reverse osmosis in remote Australian communities
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Date
2009Author
Richards, L. A.
Richards, B. S.
Rossiter, H.M.A.
Schäfer, Andrea
Metadata
Abstract
In order to provide safe drinking water in isolated communities where water supply and
electrical infrastructure is limited, a system combining solar energy and advanced water treatment
technology (a two-staged membrane process with ultrafiltration followed by nanofiltration/reverse
osmosis) has been developed. The objective of this study is to model the speciation of commonly
occurring and sometimes health-threatening trace contaminants, and then to evaluate the impact of
speciation on fluoride, arsenic, and magnesium retention by nanofiltration/reverse osmosis. A series
of experiments were performed in central Australia in late 2005 to assess elemental retention with four
different membrane modules (BW30, ESPA4, NF90, and TFC-S) at various pH values between 3 and
11 at two different source waters (Pine Hill Station and Ti Tree Farm). The removal of fluoride and
arsenic was observed to be independent of pH, while magnesium removal is pH dependent.
Compound speciation is considered to explain dependence observations. Membrane type was found
to impact retention. The results obtained in this study will provide valuable information on the
reliability and the optimization windows of the renewable energy powered desalination system that has
been developed