Abstract: A separation device for a fluid purification device is provided, the separation device comprising: at least three concentric enclosures including an outermost enclosure and an innermost enclosure and defining at least two concentric cavities; a plurality of spiral-shaped channels formed in each of the at least two concentric cavities, so that fluid can flow through said plurality of spiral-shaped channels; a fluid inlet, for receiving fluid, located in an upper section of an outermost cavity among the at least two concentric cavities, the fluid inlet corresponding to a gas outlet; a solids outlet, for discharging solids comprised in the fluid, located in a lower section of the separation device; and a liquid outlet, for discharging liquid comprised in the fluid, located in an upper section of at least one inner cavity among the at least two concentric cavities.

Abstract: The invention is directed to a process for the simultaneous removal of BOD and phosphate from a liquid containing ammonium, BOD, phosphate and magnesium, the method comprising: feeding the liquid to a reactor containing BOD-oxidising biomass; ensuring that the liquid in the reactor contains an excess to stoichiometry of ammonium and magnesium relative to phosphate, wherein the stoichiometry is related to the stoichiometry of struvite; oxidising at least part of the BOD; adjusting the pH of the liquid in the reactor at a desired value; forming solid material in the reactor, the solid material comprising struvite; separating at least part of the solid material from the reactor effluent; returning a part of the solid material to the reactor. The invention is also directed to a reactor for this process. The advantage of the process and the apparatus is that in one reactor both BOD and phosphate are removed from the liquid.