Process for treating concentrated salt solutions containing DOC
A process for removing DOC (dissolved organic carbon) from a concentrated salt solution containing DOC by contacting the salt solution with a coagulant/flocculant such that the DOC becomes insoluble and removing the insoluble DOC from the salt solution.
1. A process for the removal of DOC from water containing DOC, said process comprising:
(i) contacting the water with ion-exchange resin to enable adsorption of DOC on the resin;
(ii) separating the resin loaded with DOC from the water;
(iii) regenerating at least a portion of the separated resin by contacting it with a concentrated inorganic salt solution containing a source of anions such that the anions exchange with DOC adsorbed on the resin;
(iv) separating the regenerated resin from the concentrated salt solution containing DOC;
(v) contacting the solution from step (iv) with a coagulant and/or flocculant such that the DOC becomes insoluble in the salt solution; and
(vi) removing the insoluble DOC of step (v) from the salt solution.
2. A process according to claim 1 wherein the ion exchange resin has a density greater than the water and the resin loaded with DOC is separated from the water by settling.
3. A process according to claim 2 wherein the resin is collected by vacuum collection.
4. A process according to claim 1 wherein the regenerated resin is separated from the concentrated salt solution containing DOC by filtering through a mesh.
5. A process for the removal of DOC from water containing DOC, said process comprising:
(i) contacting the water with ion-exchange resin to enable adsorption of DOC on the resin;
(ii) separating the resin loaded with DOC from the water;
(iii) regenerating at least a portion of the separated resin and recycling the remainder to step (i), wherein the resin is regenerated by contacting it with a concentrated inorganic salt solution containing a source of anions such that the anions exchange with the DOC adsorbed on the resin;
(iv) separating the regenerated resin from the concentrated inorganic salt solution containing DOC;
(v) recycling the regenerated resin back to step (i);
(vi) contacting the separated inorganic salt solution from step (iv) with a coagulant and/or flocculant such that the DOC becomes insoluble in the salt solution;
(vii) removing insoluble DOC from the salt solution to regenerate concentrated inorganic salt solution; and
(viii) recycling concentrated inorganic salt solution back to step (iii).
6. A process according to claim 1 which is used in the treatment of a raw water source to produce potable water for distribution and consumption.
7. A process according to claim 5 wherein the regenerated salt solution obtained from step (vii) is treated with a base.
8. A process according to claim 5 wherein the regenerated concentrated salt solution is obtained from step (vii) has a PH of 7-II.
9. A process according to claim 1 wherein the ion-exchange resin is magnetic ion-exchange resin.
10. A process according to claim 9 wherein the magnetic ion-exchange is MIEX® resin.
11. A process according to claim 1 wherein the coagulant/flocculant is selected from aluminum sulphate (alum), polyaluminum chloride, aluminum chlorohydrate, polyaluminium chlorohydrate, ferric chloride, ferric sulphate, polymerised ferric sulphate, polyDADMACS, polyacrylamide emulsion polymers, coagulant aids, and filter aids.
12. A process according to claim 11 wherein the coagulant/flocculant is selected from Ferric Chloride, Ferric Sulphate, polymerised Ferric sulphate and Aluminum sulphate (Alum).
13. A process according to claim 1 wherein the concentrated salt solution is a concentrated inorganic salt solution selected from NaCl, KCl, NH 4 Cl, CaCl 2 and MgCl 2 or mixtures thereof.
14. A process according to claim 13 wherein the concentrated salt solution is a brine solution.
15. A process according to claim 13 wherein the salt solution has a concentration of greater than 1.5 M, or 100 grams of total dissolved salt in a mixture of salts per litre of water.
16. A process according to claim 1 wherein the step of contacting the salt solution with a coagulant and/or flocculant is conducted under acidic conditions.
17. A process according to claim 16 wherein the pH is less than 3.
18. A process according claim 1 wherein the step of contacting the salt solution with a coagulant and/or flocculant further includes the addition of an acid.
19. A process according to claim 18 wherein the acid is selected from HCl, HNO 3 and H 2 SO 4 .
20. A process according to claim 19 wherein the acid is HCl.
21. A process according to claim 18 wherein the pH is about 2.
22. A process according to claim 1 wherein the insoluble DOC is removed from the salt solution by filtration.
23. A process according to claim 22 wherein the filtration method is a plate and frame filter process.
24. A process according to claim 1 wherein the DOC which is removed from the salt solution is used as a fertilizer, feed-stock, soil conditioner, or health supplement.
25. A process according to claim 1 wherein the DOC which is removed from the salt solution is used as land fill.