Patent ID: 7390416

Claim:
A method for treating wastewater, comprising: (a) adding a metal sulfate comprising aluminum sulfate or alum to a wastewater containing metals comprising molybdenum and having a pH of from about 6 to 12, whereby the pH of the wastewater is lowered to from about 3.5 to 6.0; (b) adding a hydroxyl providing base to the wastewater whereby the pH of the wastewater is raised to from about 8 to 10; (c) adding a metal sulfide complex comprising an iron sulfide complex with a component comprising sodium dimethyldithiocarbamate to the wastewater; (d) adding an acid to the wastewater whereby the pH of the wastewater is lowered to from about 3.2 to 3.7; (e) adding a flocculating agent to the wastewater whereby the metals are precipitated as a precipitate; and (f) separating the precipitate from the wastewater.