Forward osmosis performance in extracting water from produced water

Produced water (PW) is a prominent brine waste in the petroleum industry, which can be reused after desalination. In this work, the influence of PW salinity variation and its composition on PW desalination through the forward osmosis process, using cellulose triacetate membrane, was investigated. In the absence of oil, increasing feed salinity from 10 to 20 g/L causes water flux to decrease from 9.43 to 7.33 LM.H. By adding 750 mg/L oil to the feed solutions with different compositions, the resulted water fluxes were almost the same and were around 7.5 LMH. The membrane fouling investigation in long-period operation (5000 min) showed a decrease of 37% in water flux. It was observed that osmotic backwashing, conducted by using 0.5 and 2 M NaCl, and chemical cleaning, treated by sodium dodecyl sulfate solution, recovered the water flux to 75% and 85% of the initial fluxes, respectively.