The potential of riverbank filtration for drinking water supplies when aquifers are brackish

摘要

The River Murray in South Eastern Australia contains turbid water, and on occasions, toxic cyanobacteria (blue green algae). For numerous small communities that obtain water supplies directly from the river, bank filtration appears to be an attractive form of natural water treatment. However the ambient groundwater of unconfined aquifers skiring some reaches of the river is saline. This paper reports a modelling study to examine the compatibility of two constraints on the quality of water recovered from bank filtration schemes; that (1) removal of cyanobacterial toxins is adequate and (2) salinity is acceptable for drinking water supplies. Adsorption and biodegradation characteristics of a cyanobacterial hepatotoxin in porous media under a range of environmental conditions were quantified in a related study and these results were summarised in the current analysis. It was found that riverbank filtration schemes could meet both criteria in a limited range of conditions, excluding locations where saline groundwater discharged to the river.