Water treatment plant demineralizing town water with reject water from an osmosis unit being recycled to a circuit for softening the water, giving two outputs of different quality

摘要

The town water treatment plant includes means of recovering the reject water (III) full of minerals from the osmosis unit (2) and recycling it and injecting it into the water (I) which has only been softened, to be sent to the first destination (A). Waste water treatment plant with a softener (1) in a first circuit (I) through which water passes to be sent to a first destination (A), and an osmosis unit (2) in a circuit (II) parallel to the first through which the softened water passes to be further demineralized and sent to a second destination (B). The means of recovering the reject water from the osmosis unit are placed in the recycling circuit (IIIa) which runs between an outlet (4) from the osmosis unit and the first circuit. This recycling circuit comprises a first counter (5) of reject water to be recycled; at least one reservoir (6) in parallel in the circuit which is pressurized for the accumulation of reject under pressure to minimize the starting of the osmosis unit; to pressure gauges (7, 8) in parallel in the circuit where one starts the osmosis unit when the reservoir(s) reach a preset pressure and the other operates a safety valve (9) to a drain connected to a second counter and improving the operation of the osmosis unit; a manometer (11) connected to the pressure gauges; a non-return valve (12) and a pressure regulator (13) are also in series in the circuit. In addition a bypass circuit (IV) controls the osmosis unit as a function of the consumption of softened and reject water in the reservoir(s). This bypass circuit comprises a flow measuring device (14) with a magnetic ludion acting as a float so its position varies as a function of the softened water used and connected to an electrical contact controlling the osmosis unit; a non-return valve in series; a manometer in a bypass line; a safety valve (17) in a bypass line which operates if the pressure regulator fails, at a preset pressure, to evacuate the reject water to the drain.