This study was carried out to find a way to limit fouling of disc-tube-type reverse osmosis membranes in the treatment of acid rinse wastewater from the fluorine manufacturing process as well as to pretreat the wastewater before it entered the membrane process. Experiments showed that the scale consisted of Ca2+, SO4-2 and F-. Complex scales were removed in a subsequent procedure where the membrane was rinsed with NaOH followed by citric acid which could consequently recover its flux up to 86%. Cleaning chemicals had to be used regularly for efficient recovery of permeate flux. Ultrasonic cleaning could also improve the recovery of permeate flux up to 83%. Calcium salts were used to remove fluoride ions. CaCl2 removed fluoride ions up to 11% more than Ca(OH)(2) at 0.5 [Ca2+]/[F-]. At acidic pH 4-7 or alkaline pH 7 and above, residual fluoride ions increased as Ca2+ reacted more efficiently with Cl-, OH-and SO4-2 rather than F-. On the other hand, fluoride ions were best removed at pH 7. Adding Ca2+ salt above pH 7 caused an increase of residual Ca2+ salt in the effluent, even if fluoride ions can be ideally removed in the form of CaF2 at a pH over 11.