A process for the treatment of industrial waste water. The process includes the steps of admixing partially-treated waste water containing precipitated impurities with a flocculating agent in a flocculation basin, directing the admixed waste water to an elongated sedimentation basin, allowing flocculated solids in the waste water to settle to the bottom of the sedimentation basin, removing the settled solids from the bottom of the sedimentation basin and directing the treated water from the sedimentation basin. The process can further include the step of adjusting the pH of the waste water to precipitate impurities in the waste water prior to the addition of the flocculation agent. The elongated sedimentation basin can include a pair of sloped sides to consolidate the settled solids at the bottom of the basin. The settled solids can then be removed by suction. The basins can be formed from the excavation or impoundment of earth in an area adjacent to a waste water-generating facility. Furthermore, the flow of the streams between basins can be controlled by overflow, with flow rates further controlled by recycle of solids and treated water. The treatment of industrial water according to the present processes allows removal of impurities such that the water is suitable for internal re-use in an operating phosphoric acid facility or release. Additionally, the process is able to treat acidic industrial waste water by the removal of impurities as a preliminary treatment stage leading to discharge of the final treated water to natural water bodies in compliance with the Federal Clean Water Act. Moreover, treated water may be processed by reverse osmosis to remove residual impurities. By employing the processes taught herein reverse osmosis becomes possible and practicable in the context of industrial waste water treatment. Treatment of waste water in accordance with the present invention will require less expensive capital equipment for the separation stages and provide a more concentrated solids stream.