Patent ID: 9688559
Date: 2017-06-27
CPC Classifications: C02F

Claim:
1. A multi-stage process for removing phosphorus, fluoride, arsenic, and other impurities from an influent solution, wherein said process includes: a first stage that comprises adjusting an influent solution to pH between approximately 6.0 to 8.0, followed by adjusting to a pH between 10.2 to 10.5 by the use of a base, and adding a flocculent to less than 100 ppm, followed by a solid/liquid separation resulting in ft removal of at least a portion of the impurities in the solids phase leaving a partially cleaned effluent having pH of at least 10.2; and a second stage in which the pH of the partially cleaned effluent is lowered to less than 6.2, adding a hydroxide to the partially cleaned effluent to increase the pH of the partially cleaned effluent to at least 7.0, and then adding a flocculent to the partially cleaned effluent followed by a removal of solids comprising impurities from the partially cleaned effluent leaving the partially cleaned effluent of at least pH 7 without the impurities comprised by the removed solids.