Forward osmosis as a pre-treatment for treating coal seam gas associated water:Flux and fouling behaviours

In this study, a bench scale forward osmosis (FO) process was operated using two commonly available FO membranes in different orientations in order to examine the removal of foulants in the coal seam gas (CSG) associated water, the water flux and fouling behaviours of the process were also investigated. After 48 h of fouling simulation experiment, the water flux declined by approximately 55 and 35% of its initial level in the TFC-PRO and CTA-PRO modes (support layer facing the feed), respectively, while the flux decline in the TFC-FO and CTA-FO modes (active layer facing the feed) was insignificant. The flux decline in PRO modes was caused by the compounding effects of internal concentration polarisation and membrane fouling. However, the declined flux was completely recovered to its initial level following the hydraulic cleaning using deionised water. Dissolved organic carbon (DOC), adenosine tri-phosphate (ATP) and major inorganic scalants (Ca, Mg and silica) in the CSG feed were effectively removed by using the FO process. The results of this study suggest that the FO process shows promising potential to be employed as an effective pre-treatment for membrane purification of CSG associated water. © 2015 Elsevier B.V. All rights reserved.

In this study, FO process used as a pre-treatment for CSG associated water was evaluated. Continuous flux decline was observed in PRO orientation of the membrane setup, while little flux decline was observed in FO mode. Contrarily, the flux decline in PRO mode was not dominated Fig 8. FEEM spectra of draw solutions after 48 h of filtration experiments. Please cite this article as: Y. Chun, et al., Forward osmosis as a pre-treatment for treating coal seam gas associated water: Flux and fouling by initial flux or permeation drag force, yet it is the compounding effect of ICP and fouling of the membrane. It was shown that using FO mode for both TFC and CTA membranes is preferable to PRO mode when treating low fouling potential CSG production water. Simple hydraulic cleaning was sufficient to achieve complete recovery of the declined flux in all membrane orientations. In general, the FO process effectively rejected dissolved inorganics and organic compounds, and microorganisms in the complex feed stream containing low concentrations of pollutants and foulants. Further investigation is needed to evaluate on using FO to pre-treat high fouling potential CSG process waters.