Process for Recovering Organics From Wastewater
Disclosed is a method for treating wastewater by removing organics, such as water-soluble organics, by catalysis in the presence of an acid. Removal of such organics is in the form of a tar which includes phenol-derived compounds.
1 . A method for treating wastewater comprising:
(a) adding an acid having a pKa value less than or equal to −1 to said wastewater which comprises water-soluble organics, wherein said water-soluble organics comprise phenols which are present in said wastewater in an amount of at least about 1 wt %, and wherein said acid catalyzes the reaction of at least a portion of said water-soluble organics to form water-insoluble organics which settle out of said wastewater thereby forming a tar and treated water which comprises less water-soluble organics than said wastewater; and
(b) separating at least a portion of said tar from said treated water.
2 . The method of claim 1 wherein said water-soluble organics further comprise oxygenated compounds selected from the group consisting of ketones, aldehydes, carboxylic acids, alcohols, ethers, esters, and combinations thereof.
3 . The method of claim 1 wherein said wastewater comprises at least about 4 wt % water-soluble organics and said treated water comprises less than about 80 wt % of said water-soluble organics contained in said wastewater.
4 . The method of claim 3 wherein said wastewater comprises at least about 5 wt % water-soluble organics and said treated water comprises less than about 75 wt % of said water-soluble organics contained in said wastewater.
5 . The method of claim 1 wherein said tar contains at least about 25 wt % of phenol-derived compounds.
6 . The method of claim 5 wherein said tar contains at least about 40 wt % of phenol-derived compounds.
7 . The method of claim 1 wherein at least 20% of said phenols contained in said wastewater become a part of said tar.
8 . The method of claim 7 wherein at least 30% of said phenols contained in said wastewater become a part of said tar.
9 . The method of claim 1 wherein, prior to the addition of said acid, said wastewater has a pH value in the range of about 2 to about 3.
10 . The method of claim 1 wherein said acid is added to said wastewater in an amount such that the concentration of said acid in said wastewater is at least about 300 ppmw, based on the total weight of said wastewater.
11 . The method of claim 10 wherein said acid is added to said wastewater in an amount such that the concentration of said acid in said wastewater is at least about 500 ppmw, based on the total weight of said wastewater.
12 . The method of claim 10 wherein said acid is added to said wastewater in an amount such that the concentration of said acid in said wastewater is at least about 1000 ppmw and no more than about 2 wt %, based on the total weight of said wastewater.
13 . The method of claim 1 wherein said acid is selected from the group consisting of sulfuric acid, hydrochloric acid, hydrobromic acid, phosphoric acid, and combinations thereof.
14 . The method of claim 13 wherein said acid is sulfuric acid.
15 . The method of claim 1 wherein, after the addition of said acid in step a), said wastewater is at a temperature of at least about 50° C.
16 . The method of claim 15 wherein, after the addition of said acid in step a), said wastewater is at a temperature of at least about 60° C. and less than about 200° C.
17 . The method of claim 1 wherein the wt % of said tar after no more than about 1 day following the addition of said acid in step a), and based on the combined weight of said treated water and said tar, is greater than about 2 wt %.
18 . The method of claim 1 wherein the wt % of said tar after no more than about 4 days following the addition of said acid in step a), and based on the combined weight of said treated water and said tar, is greater than about 3 wt %.
19 . The method of claim 1 wherein the wt % of said tar after no more than about 20 days following the addition of said acid in step a), and based on the combined weight of said treated water and said tar, is greater than about 4 wt %.