Water treatment installation

• US 6,349,835 B1
• Filed: 01/16/2001
• Issued: 02/26/2002
• Est. Priority Date: 07/17/1998
• Status: Expired due to Term

• Current Assignee: PolyMem Ltd.
• Original Assignee: PolyMem Ltd.
• Inventors: Saux, Franc, Bontemps, Jean-Claude, Espenan, Jean-Michel
• Primary Examiner(s): KIM, SUN U
• Application Number:
  US09/743,716
• Time in Patent Office: 406 Days
• Field of Search: 210/194, 210/195.1, 210/195.2, 210/252, 210/253, 210/257.2, 210/258, 210/295, 210/321.69, 210/418, 210/420, 210/424, 210/425, 210/427, 210/433.1
• US Class Current: 210/427
• CPC Class Codes: B01D 2311/04 Specific process operations in the feed stream; Feed pretreatment
• CPC Class Codes: B01D 2311/2649 Filtration
• CPC Class Codes: B01D 2317/04 Elements in parallel
• CPC Class Codes: B01D 2321/04 Backflushing
• CPC Class Codes: B01D 2321/14 Use of concentrate
• CPC Class Codes: B01D 61/025 Reverse osmosis; Hyperfiltration
• CPC Class Codes: B01D 61/145 Ultrafiltration
• CPC Class Codes: B01D 61/58 Multistep processes
• CPC Class Codes: B01D 65/02 Membrane cleaning or sterilisation ; Membrane regeneration
• CPC Class Codes: C02F 1/44 by dialysis, osmosis or reverse osmosis general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268
• CPC Class Codes: C02F 1/441 by reverse osmosis
• CPC Class Codes: C02F 1/444 by ultrafiltration or microfiltration
• CPC Class Codes: C02F 2303/16 Regeneration of sorbents, filters

Abstract

The invention concerns a water treatment method and installation, which consist in subjecting the water to be treated to membrane filtration (1) to satisfy the requirement for a relatively high flowrate of water for ordinary use (UF), subjecting the water that has been subjected to membrane filtering to reverse osmosis filtering (2) to satisfy the requirement for a smaller flowrate of water of improved quality (OS) and, outside periods of production of water filtered by reverse osmosis, sweeping the upstream face of the osmosis membrane (9) with the flow of membrane-filtered water drawn off to be consumed.

Claims

1. A water treatment installation including:

a supply of water to be treated,

a membrane filter unit (1) having an inlet (3) connected to said supply (4) of water to be treated and an outlet (9),

a reverse osmosis filter unit (2) including at least one osmosis membrane (9) and having;

a first-filtered water inlet (8) which is connected to the outlet (7) of said membrane filter unit (1) and located upstream of said osmosis membrane (9),

an osmosis-treated water outlet (10) which is located downstream of said osmosis membrane (9) and connected to an osmosis-treated water outlet (OS) of the installation,

a first-filtered water outlet (11) which is located upstream of the osmosis membrane (9) and connected to a first-filtered water outlet (UF) of the installation,

said first-filtered water inlet (8) and outlet (11) of the reverse osmosis filter unit (2) being disposed so that the flow of first-filtered water drawn off to be consumed at the first-filtered water outlet of the installation flows from said inlet (8) to said outlet (11) through the reverse osmosis filter unit (2) on the upstream side of the osmosis membrane (9) and sweeps the upstream face of the osmosis membrane,

characterised in that the first filter unit is a membrane filter unit (1) including at least two filter modules (14) in parallel each having an inlet for water to be treated connected to said inlet (3) of the membrane filter unit (1) and a treated water outlet connected to said outlet (7) of the membrane filter unit (1), and

in that the installation further includes;

a circuit for individually cleaning the modules of the membrane filter unit by circulating membrane-filtered water from said outlet (11) of the reverse osmosis filter unit, (2) in the reverse flow direction, which cleaning circuit includes a first circuit (13) between the membrane-filtered water outlet of the reverse osmosis filter unit (2) and the respective outlets of the modules (14) of the membrane filter unit (1) and a second circuit (15) connecting the respective inlets of the modules (14) of the membrane filter unit (1) to a common drain, and

respective selector means (16) at the inlet and the outlet of each module (14) adapted to assure selectively for each module (14) either a connection in the forward flow direction between the inlet (3) and the outlet (7) of the membrane filter unit (1) or a connection in the reverse flow direction between the first circuit (13) and the second circuit (15) of the cleaning circuit.

2. An installation according to claim 1, characterised in that it includes a membrane-filtered water storage tank (12) between the membrane-filtered water outlet (11) of the reverse osmosis filter unit (2) and the membrane-filtered water outlet of the installation.

3. An installation according to claim 1, characterised in that the cleaning circuit includes a cleaning product storage tank (17) which is in parallel with said first circuit (13) and can be selectively inserted (8) into the first circuit (13).

4. An installation according to claim 1, characterised in that the membrane filter unit (1) includes at least three membrane filter modules (14) in parallel.

5. An installation according to claim 4, characterised in that it includes control means for the selector means (16) such that two membrane filter modules in parallel supply filtered water to the third module for cleaning it.

6. An installation according to claim 1, characterised in that the membrane filter unit is an ultrafiltration unit.

7. An installation according to claim 1, characterised in that a device (5) for coarse filtering of the water to be treated is provided on the upstream side of the membrane filter unit.

8. An installation according to claim 1, characterised in that a booster pump (6) is provided on the upstream side of the membrane filter unit.