Iron Removal from Oilfield Produced Water by Chemical Precipitation and Filtration

Effect of pH in the oil field produced water on iron removal and effluent turbidity was explored by chemical precipitation and a filtration process using sodium hydroxide and porous ceramic filtration media. Mechanisms of iron removal and inhibition of electrochemical corrosion on the treatment device were discussed. The present investigation showed that influent pH had a remarkable influence on iron removal, effluent turbidity and anti- corrosion of treatment devices. Iron removal effectiveness was poor, and corrosion of the treatment device could not be inhibited atpH<7. Optimal pH was about 8.3, at which good efficiency of iron removal and anti-corrosion of treatment devices was achieved. Effluent quality met the Al quality standards of recommended indexes in SY/T5329-94. Its turbidity remained constant after 2.5 h. However, effluent turbidity at other pH readings rose gradually because of ferrous oxidation. Major removal methods for iron included gravity settling and filtration.