Abstract:
Applying pre-treatments to remove dissolved organic matter from reverse osmosis (RO) feed can help to
reduce organic fouling of the RO membrane. In this study the performance of granular activated carbon
(GAC), a popular adsorbent, and purolite A502PS, an anion exchange resin, in removing effluent organic
matter (EfOM) from RO feed collected from a water reclamation plant located at Sydney Olympic Park,
Australia were evaluated and compared through adsorption equilibrium, kinetics and fluidized bed
experiments. The maximum adsorption capacity (Qmax) of GAC calculated from the Langmuir model with
RO feed was 13.4 mg/g GAC. The operational conditions of fluidized bed columns packed with GAC and
purolite A502PS strongly affected the removal of EfOM. GAC fluidized bed with a bed height of 10cm and
fluidization velocity of 5.7 m/h removed more than 80% of dissolved organic carbon (DOC) during a 7 h
experiment. The average DOC removal was 60% when the bed height was reduced to 7 cm. When
comparing GAC with purolite A502PS, more of the laterwas required to remove the same amount of DOC.
The poorer performance of purolite A502PS can be explained by the competition provided by other
inorganic anions present in RO feed. A plug flow model can be used to predict the impact of the amount of
adsorbent and of the flow rate on removal of organic matter from the fluidized bed column.
