SYSTEMS AND METHODS FOR UPGRADING CONVENTIONAL ACTIVATED SLUDGE PLANTS

• US 20200131066A1
• Filed: 04/21/2017
• Published: 04/30/2020
• Est. Priority Date: 04/21/2017
• Status: Active Application

• Current Assignee: BL Technologies Inc. (Ashland Global Holdings, Inc.)
• Original Assignee: General Electric Company
• Inventors: COTE, Pierre Lucien
• Application Number:
  US16/606,195
• Publication Number:
  US 20200131066A1
• Time in Patent Office: Days
• CPC Class Codes: B01D 2311/08 Specific process operations in the concentrate stream
• CPC Class Codes: B01D 2311/25 Recirculation, recycling or bypass, e.g. recirculation of concentrate into the feed
• CPC Class Codes: B01D 2311/2523 to feed side
• CPC Class Codes: B01D 2311/2688 Biological processes
• CPC Class Codes: B01D 2315/06 Submerged-type; Immersion type
• CPC Class Codes: B01D 61/145 Ultrafiltration
• CPC Class Codes: B01D 61/147 Microfiltration
• CPC Class Codes: B01D 61/16 Feed pretreatment
• CPC Class Codes: C02F 2301/043 Treatment of partial or bypass streams
• CPC Class Codes: C02F 2303/24 Separation of coarse particles, e.g. by using sieves or screens
• CPC Class Codes: C02F 3/102 Permeable membranes
• CPC Class Codes: C02F 3/121 Multistep treatment
• CPC Class Codes: C02F 3/1221 comprising treatment of the recirculated sludge
• CPC Class Codes: C02F 3/1273 Submerged membrane bioreactors
• CPC Class Codes: C02F 3/208 Membrane aeration C02F3/201 takes precedence
• CPC Class Codes: Y02W 10/10 Biological treatment of water, waste water, or sewage

Abstract

A conventional activated sludge wastewater treatment plant is upgraded by adding one or more of a membrane filtration unit, a membrane aerated biofilm reactor (MABR) unit, and a screen. The membrane filtration unit is added between a process tank and the secondary clarifier. The membrane filtration unit extracts treated effluent at a rate up to 25% of the influent flow rate. The plant is not converted into a membrane bioreactor (MBR) since the MLSS concentration is still less than 4,000 mg/L. The membrane-aerated biofilm reactor (MABR) unit is added to a process tank of the plant and provides attached growth biological treatment. The screen extracts solids from water flowing to the process tanks. When optionally used in combination, the added units and processes increase the capacity of the primary separation, biological processing and secondary separation functions of the plant. The influent flow rate may be increased.

Claims

1. A wastewater treatment process comprising steps of:

biological treatment to produce mixed liquor;

separation of a first portion of an effluent from the mixed liquid through a filtration membrane; and

,

separation of a second portion of an effluent from the mixed liquid through a secondary clarifer.

2. The process of claim 1 wherein the first portion is up to 25% of the combined first portion and second portion.

3. The process of claim 1 wherein the mixed liquor suspended solids concentration is 4000 mg/L or less.

4. The process of claim 1 wherein solids separated by the filtration membrane remain in the mixed liquor or flow to the secondary clarifer.

5. The process of claim 1 wherein solids separated by the filtration membrane are mixed with return activated sludge.

6. The process of claim 1 comprising screening influent in parallel with a primary clarifier.

7. The process of claim 1 comprising screening return activated sludge.

8. The process of claim 1 comprising attached and suspended growth biological processes.

9. A wastewater treatment process comprising steps of:

biological treatment of primary effluent attached and suspended growth biological processes to produce mixed liquor;

separation of a treated effluent from the mixed liquid;

return of activated sludge to the biological treatment; and

,

one or more of screening influent in parallel with a primary clarifier and screening return activated sludge.

10. A modified conventional activated sludge wastewater treatment plant comprising:

one or more process tanks or other biological reactors;

a secondary clarifier; and

,

one or more of a) a filtration membrane, b) a screen in parallel with a primary clarifier, c) a screen configured to remove solids from return activated sludge, and d) an attached medium in the one or more process tanks or other biological reactors.

11. The plant of claim 10 comprising a filtration membrane located in a process tank or in a separate tank having a rejected solids outlet connected to the secondary clarifier.

12. The plant of claim 10 comprising a filtration membrane in a membrane tank between the one or more process tanks or other biological reactors and the secondary clarifier.

13. The plant of claim 10 comprising a screen in parallel with a primary clarifier.

14. The plant of claim 10 comprising a screen configured to remove solids from return activated sludge.

15. The plant of claim 10 comprising an attached medium in the one or more process tanks or other biological reactors.