Abstract: An apparatus for purifying water, comprising an ion exchanger with a water inlet and a product outlet, connected to an inlet of a first filtration step, which comprises one or more nano- and/or RO-filtration membranes and is provided with a first permeate outlet and a first concentrate outlet. According to a first embodiment, the apparatus comprises a subsequent filtration step in which an inlet is connected with the first concentrate outlet, which subsequent filtration step comprises one or several subsequent nano- and/or RO-filtration membranes, and which is provided with a second permeate outlet and second concentrate outlet, which second concentrate outlet is optionally connected with an inlet of a subsequent filtration step.

Abstract: A process is described for the biological treatment of waste water containing a specific component such as ammonia, wherein the waste water together with surplus sludge from an activated sludge reactor is treated in a bioaugmentation reactor, applying a hydraulic retention time in the continuously or discontinuously operated reactor which is shorter than the sludge retention time by retaining part of the sludge in the reactor and continuing the use of the separated part in the reactor. The non-retained part of the sludge, together with the effluent of the bioaugmentation reactor, is added to the activated sludge reactor.

Abstract: A membrane filtration for removing floating substances and salts from a liquid, uses vertically positioned capillary or tube membranes which are suitable for performing nano or hyper-filtration. Repeatedly and consecutively the following steps are performed: a) a permeate is produced without discharge of concentrate for a predetermined period of time; b) then a gas, for example air, is guided along side the membrane, at least almost without discharge of permeate and without discharge of concentrate; c) and finally a concentrate is discharged without discharge of permeate. During step a) and step c) use can be made of a combined supply of liquid and gas. An apparatus for performing this method is described as well.

Abstract: A process is provided for the removal of organic substances (TOC), pesticides or other specific compounds from an aqueous salt solution, for example from a regenerate derived from water purification. The TOC-containing aqueous salt solution is treated in a desalination membrane according to the dead-end principle, wherein neither longitudinal flow over the membrane with air and/or water, nor continuous concentrate discharge takes place, after which the obtained permeate is reused, and the concentrate obtained after flushing is discharged. The TOC-containing aqueous salt solution is introduced at the feed side of the membrane module at a flux of 5-75 1/m2·h, a feed pressure of 4-12 bars for 30-40 minutes, while the obtained TOC-depleted permeate is discharged. Preferably, operation takes place at a flux of 15-25 1/m2·hr, a pressure of approximately 8 bars, and the duration of treatment is approximately 30 minutes.