Utilisation of a purification device (10a; 10b) for a purification of water contaminated by microorganisms and/or by inanimate suspended matter, with at least one first receiving region (12a; 12b) for receiving a contaminated liquid (14a; 14b), with at least one second receiving region (16a; 16b) for receiving a purified liquid (18a; 18b) and with a membrane unit (20a; 20b) that is arranged between the first receiving region (12a; 12b) and the second receiving region (16a; 16b), the at least one membrane unit (20a; 20b) comprising an electroosmotic membrane (22a; 22b) which serves at least partially as a separating agent between the first receiving region (12a; 12b) and the second receiving region (16a; 16b), the electroosmotic membrane (22a; 22b) having a first electrode (24a; 24b) on a first surface and having a second electrode (26a; 26b) on a second surface situated opposite the first surface, the electroosmotic membrane (22a; 22b) being configured, when a voltage is applied, to transport a liquid from the first receiving region (12a; 12b) into the second receiving region (16a; 16b) via an electroosmotic effect, characterised in that in a purification step for a purification of the contaminated water, in the first receiving region (12a; 12b) a voltage is applied to the electrodes (24a, 26a; 24b, 26b) of the electroosmotic membrane (22a; 22b) and water is transported from the first receiving region (12a; 12b) into the second receiving region (16a; 16b) via an electroosmotic effect, wherein both the pumping and the separation characteristics of the electroosmotic membrane (22a; 22b) are defined by an appropriate selection of the pore size of the electroosmotic membrane (22a; 22b), wherein depending on the pore size different materials are separated by the electroosmotic membrane (22a; 22b), wherein the electroosmotic membrane has a pore size between 0.1 μm and 2 μm, wherein only the electroosmotic membrane (22a; 22b) serves as a separating agent between the receiving regions (12a, 16a; 12b, 16b). the at least one membrane unit (20a; 20b) comprising an electroosmotic membrane (22a; 22b) which serves at least partially as a separating agent between the first receiving region (12a; 12b) and the second receiving region (16a; 16b), the electroosmotic membrane (22a; 22b) having a first electrode (24a; 24b) on a first surface and having a second electrode (26a; 26b) on a second surface situated opposite the first surface, the electroosmotic membrane (22a; 22b) being configured, when a voltage is applied, to transport a liquid from the first receiving region (12a; 12b) into the second receiving region (16a; 16b) via an electroosmotic effect, characterised in that in a purification step for a purification of the contaminated water, in the first receiving region (12a; 12b) a voltage is applied to the electrodes (24a, 26a; 24b, 26b) of the electroosmotic membrane (22a; 22b) and water is transported from the first receiving region (12a; 12b) into the second receiving region (16a; 16b) via an electroosmotic effect, wherein both the pumping and the separation characteristics of the electroosmotic membrane (22a; 22b) are defined by an appropriate selection of the pore size of the electroosmotic membrane (22a; 22b), wherein depending on the pore size different materials are separated by the electroosmotic membrane (22a; 22b), wherein the electroosmotic membrane has a pore size between 0.1 μm and 2 μm, wherein only the electroosmotic membrane (22a; 22b) serves as a separating agent between the receiving regions (12a, 16a; 12b, 16b).