Feasibility of using nf/ro membranes to remove pollutants from coal bed methane/oil-produced water

Management of produced water (PW) has become a major factor in the feasibility of gas field development. Surface discharge of large volumes of PW has already had many adverse environmental affects such as stream bank erosion, change in natural vegetation, salt deposition etc. Further, given the scarcity of water in the western United States, produced water which is a waste product from oil and gas drilling is in fact a very valuable natural resource. Treatment of PW requires de-oiling and demineralizing the water. However, membrane fouling constitutes a major obstacle for the application of membrane-based processes for the treatment of PW for beneficial uses. This investigation focuses on the characterization of water flux using three commercially available membranes obtained from FILMTEC Corporation: BW 30 (reverse osmosis), NF 90 (nanofiltration) and NF 270 (nanofiltration). The results obtained showed that water flux through the NF 270 membrane is much higher compared to NF 90 and BW 30. The flux of PW from oilfields is low as compared to PWs from CBM production regardless of the membrane selected. The presence of total dissolved solids and hydrocarbons leads to greater water flux decline for PW from oilfields. There is progressive decrease of water flux during filtration due to the membrane fouling. Membrane fouling was observed by field emission scanning electron microscope (FESEM). Membrane fouling by organic substances was identified by using attenuation total reflection - Fourier transform infrared analysis (ATR-FTIR). On the other hand, X-ray photoelectron spectroscopy (XPS) revealed the inorganic fouling