METHOD FOR CONDITIONING A WASTE SOLUTION CONTAINING ORGANIC SUBSTANCES AND METALS IN IONIC FORM, OBTAINED DURING WET-CHEMICAL CLEANING OF CONVENTIONAL OR NUCLEAR PLANTS
A method is provided for conditioning a waste solution obtained during the wet-chemical cleaning of conventional or nuclear plants and containing organic substances and metals in ionic form. At least a portion of the organic substance is degraded by electrochemical treatment or UV radiation of the waste solution, at least one metal precipitates by the addition of phosphoric acid and a resultant phosphate precipitate is removed from the waste solution.
1 . A process for conditioning a waste solution obtained in the course of wet-chemical cleaning of conventional or nuclear plants and including at least one organic substance and at least one metal in ionic form, the method comprising the following steps:
degrading at least a portion of the organic substance by electrochemical treatment of the waste solution;
precipitating at least one metal by addition of phosphoric acid to form a phosphate precipitate; and
removing the phosphate precipitate from the waste solution.
2 . The process according to claim 1 , which further comprises carrying out the electrochemical treatment step with an anode having an oxygen overpotential.
3 . The process according to claim 1 , wherein a further oxo compound is present in the waste solution as well as the phosphoric acid.
4 . The process according to claim 1 , which further comprises adding to the waste solution an oxidizing agent being effective with respect to the at least one organic substance.
5 . The process according to claim 4 , which further comprises adding hydrogen peroxide to the waste solution as an oxidizing agent.
6 . The process according to claim 1 , which further comprises carrying out the step of adding the phosphoric acid at a time when the at least one organic substance is yet to be fully degraded.
7 . The process according to claim 6 , which further comprises carrying out the step of adding the phosphoric acid at a start of the process.
8 . The process according to claim 1 , which further comprises carrying out the step of adding the phosphoric acid in a stoichiometric amount with regard to metal content.
9 . The process according to claim 1 , which further comprises establishing a pH of 3 to 9 in the waste solution.
10 . The process according to claim 1 , which further comprises treating iron-containing waste solutions with the process.
11 . The process according to claim 1 , which further comprises conditioning, with the process, a waste solution including an organic complex of a metal.
12 . A process for conditioning a waste solution obtained in the course of wet-chemical cleaning of conventional or nuclear plants and including at least one organic substance and at least one metal in ionic form, the method comprising the following steps:
degrading at least a portion of the organic substance by irradiation of the waste solution with UV light;
precipitating at least one metal by addition of phosphoric acid to form a phosphate precipitate; and
removing the phosphate precipitate from the waste solution.
13 . The process according to claim 12 , which further comprises adding to the waste solution an oxidizing agent being effective with respect to the at least one organic substance.
14 . The process according to claim 13 , which further comprises adding hydrogen peroxide to the waste solution as an oxidizing agent.
15 . The process according to claim 12 , which further comprises carrying out the step of adding the phosphoric acid at a time when the at least one organic substance is yet to be fully degraded.
16 . The process according to claim 15 , which further comprises carrying out the step of adding the phosphoric acid at a start of the process.
17 . The process according to claim 12 , which further comprises carrying out the step of adding the phosphoric acid in a stoichiometric amount with regard to metal content.
18 . The process according to claim 12 , which further comprises establishing a pH of 3 to 9 in the waste solution.
19 . The process according to claim 12 , which further comprises treating iron-containing waste solutions with the process.
20 . The process according to claim 12 , which further comprises conditioning, with the process, a waste solution including an organic complex of a metal.