Patent ID: 6117333
Filing Date: 2000-09-12
Classification: C02F,Y10S

Abstract:
A process for removing hydrocarbons, arsenic and mercury from a feed wastewater, said process comprising:(a) contacting said feed wastewater with an oxidizing agent to oxidize said arsenic contained in said feed wastewater from an oxidation state of less than +5 to an oxidation state of +5 to form oxidized arsenic and to raise the Oxidation Reduction Potential of said feed wastewater to a value below +400 mv;(b) contacting the wastewater from step (a) containing said oxidized arsenic with ferric ions for a sufficient time to form precipitates containing iron and said oxidized arsenic, respectively;(c) adding a sludge-contracting material to the wastewater of step (b) to consolidate said precipitates and form a sludge containing at least a portion of said oxidized arsenic, at least a portion of said mercury and at least a portion of said hydrocarbons; and(d) separating said sludge from the wastewater of step (c) to form a cleaned wastewater having a reduced concentration of hydrocarbons, arsenic, and mercury as compared to said feed wastewater.