Capacitive electrostatic process for inhibiting the formation of biofilm deposits in membrane-separation systems

• US 20050263386A9
• Filed: 03/09/2004
• Published: 12/01/2005
• Est. Priority Date: 02/16/1994
• Status: Abandoned Application

• Current Assignee: Pitts M. Michael Jr, Rodrigo F.V. Romo
• Original Assignee: Pitts M. Michael Jr, Rodrigo F.V. Romo
• Inventors: Romo, Rodrigo F.V., Pitts, M. Michael Jr.
• Application Number:
  US10/796,814
• Publication Number:
  US 20040173451A1
• Time in Patent Office: Days
• US Class Current: 204/164
• CPC Class Codes: B01D 2311/04 Specific process operations in the feed stream; Feed pretreatment
• CPC Class Codes: B01D 2311/2603 Application of an electric field, different from the potential difference across the membrane
• CPC Class Codes: B01D 2321/22 Electrical effects
• CPC Class Codes: B01D 61/025 Reverse osmosis; Hyperfiltration
• CPC Class Codes: B01D 61/04 Feed pretreatment
• CPC Class Codes: B01D 61/145 Ultrafiltration
• CPC Class Codes: B01D 61/16 Feed pretreatment
• CPC Class Codes: B01D 65/08 Prevention of membrane fouling or of concentration polarisation
• CPC Class Codes: C02F 1/441 by reverse osmosis
• CPC Class Codes: C02F 1/444 by ultrafiltration or microfiltration
• CPC Class Codes: C02F 1/48 with magnetic or electric fields C02F1/46 takes precedence
• CPC Class Codes: C02F 2303/04 Disinfection
• CPC Class Codes: C02F 2303/08 Corrosion inhibition
• CPC Class Codes: C02F 2303/20 Prevention of biofouling
• CPC Class Codes: C23F 15/00 Other methods of preventing corrosion or incrustation

Abstract

A high-voltage capacitive electrostatic device is used to improve the performance of membrane-separation processes, particularly reverse-osmosis units, wherein species of a given ionic polarity are separated from water. The device is immersed in the water flowing across the membranes and is operated continuously at very high voltages, preferably greater than 30,000 volts DC. The charge on the wetted surface of the suspended particles is altered by the electrostatic field so generated and is found to reduce biofilm formation, thereby materially enhancing the performance of the membrane-separation system. The application of high-voltage electrostatic fields is also found to reduce corrosion of metallic surfaces in the system.

Claims

1. A method for reducing the formation of biofilm deposits on a wall in a water system comprising the steps of:

providing a capacitive electrostatic generator adapted to create an electrostatic field;

immersing said electrostatic generator in a body of water in the water system, the water system being connected to an electrical ground relative to an electromotive force available for energizing the electrostatic generator; and

energizing said electrostatic generator with said electromotive force, such that a corresponding electrostatic field is created between said generator immersed in the water system and said electrical ground without measurable current leakage in the body of water;

wherein said capacitive electrostatic generator comprises a vitrified ceramic tube of unibody construction having an integrally-sealed end defining an inner cavity with an inner wall;

conductive material contained within said inner cavity and disposed in intimate contact with said inner wall;

electrically-insulated sealing means for providing hermetic closure to said inner cavity; and

electrical means for energizing said conductive material with a static electromotive force.

2. The method of claim 1, wherein said voltage is greater than about 10,000 volts DC.

3. The method of claim 1, wherein said voltage is greater than about 30,000 volts DC.