Patent ID: 9108233
Filing Date: 2015-08-18
Classification: B09C

Abstract:
1. A batch process for remediation of soils contaminated with toxic metals and organic pollutants, in a series of batch processes, said batch process comprising: (a) washing a solid phase of contaminated soil with washing solution, said washing solution comprising a chelating agent, wherein soluble complexes of the chelating agent with the toxic metals are formed in the washing solution; (b) separating the solid phase from the washing solution by filtration to obtain a washed solid phase and process water; (c) rinsing the washed solid phase with a rinsing solution to obtain a rinsed solid phase and a used rinsing solution; (d) alkalinisation of the process water obtained in step (b) and of the used rinsing solution of step (c) to a pH value above pH10 using a calcium containing base, thereby precipitating metal hydroxides; (e) removing the precipitated metal hydroxides from the process water of step(d); (f) subsequently acidifying the process water of step (e) to below pH 3, thereby precipitating the chelating agent in the process water; (g) subsequently removing said precipitated chelating agent from the process water; (h) subsequently treating said process water by oxidative degradation in an oxidation process, thereby obtaining a cleansed process water; wherein a first part of said cleansed process water of step (h) is used as rinsing solution in step (c) of the subsequent batch process in said series of batch processes, and a second part of said cleansed process water of step (h) is combined with removed precipitated chelating agent from step (g) to prepare a washing solution used in step (a) of the subsequent batch process in said series of batch processes.