Process for reducing contaminants in process water and/or condensate

1 . A process for reducing the contaminants in contaminated process water and/or condensate, wherein said process comprises the steps of:

(a) adding from 1 ppm to 1,000 ppm of a first coagulant having a having a mean volume average of from about 1 micron to about 25 microns to the process water and/or condensate to be treated;

(b) then adding from 1 ppm to 1,000 ppm of a second coagulant having a mean volume average of from about 40 microns to about 200 microns;

(c) filtering said process water and/or condensate.

2 . The process of claim 1 wherein the temperature of the treated process water and/or condensate is from 80° C. to 100° C.

3 . The process of claim 2 wherein the emulsion breaker is a cationic melamine formaldehyde coagulant.

4 . The process of claim 3 wherein the coagulant is a mannich-tannin coagulant.

5 . The process of claim 4 wherein the filter used for filtering is an upflow sand filter.

6 . The process of claim 5 wherein the process water and/or condensate is generated from the production of alumina from bauxite ore.

7 . The process of claim 6 wherein the process used to prepare the alumina from bauxite ore is the Bayer process.

8 . The process of claim 7 wherein the purified process water and/or condensate is recycled in the Bayer process for converting bauxite ore to alumina.

9 . The process of claim 1 , 2 , 3 , 4 , 5 , 6 , 7 , or 8 wherein the purified process water and/or condensate is used as boiler feedwater.