EP-4739632-A1 - A MODIFIED MEMBRANE BIOREACTOR (MBR) SYSTEM AND METHOD FOR REMOVING PER- AND POLYFLUOROALKYL SUBSTANCES (PFAS) FROM A FLOW OF WASTEWATER AND/OR LANDFILL LEACHATE

Abstract

A MBR system for removing PFAS from a flow of wastewater and/or landfill leachate includes an MBR which receives the flow of wastewater and/or landfill leachate having PFAS therein. An impregnation subsystem receives a flow of mixed liquor from the MBR and a predetermined amount PAC to maintain a predetermined ratio of PAC to biomass in the MBR and blends the biomass with the PAC to form PAC-impregnated biological flocs. An outlet coupled to impregnation subsystem outputs a flow of PAC-impregnated biological flocs to the MBR such that the PAC-impregnated biological flocs in the MBR adsorb to and remove a majority of the PFAS from the flow of wastewater and/or landfill leachate and the MBR outputs a flow of treated wastewater and/or landfill leachate having a majority of the PFAS removed.

Inventors

• RODRIGUEZ, PAUL
• WOODARD, Steven, E.
• KEMPISTY, DAVID

Assignees

• Emerging Compounds Treatment Technologies, Inc.

Dates

Publication Date

20260513

Application Date

20240216

Claims (20)

1. 1. A modified membrane bioreactor (MBR) system for removing per- and polyfluoroalkyl substances (PFAS) from a flow of wastewater and/or landfill leachate, the system comprising: an MBR configured to receive the flow of wastewater and/or landfill leachate having PFAS therein, the MBR including biomass, a diffuser subsystem, and a membrane filter subsystem; an impregnation subsystem including at least one impregnation tank and at least one mixer, the impregnation subsystem configured to receive a flow of mixed liquor from the MBR and a predetermined amount powered activated carbon (PAC) to maintain a predetermined ratio of PAC to biomass in the MBR and configured to blend the biomass with the PAC to form PAC-impregnated biological flocs; and an outlet coupled to the at least one impregnation tank configured to output a flow of PAC-impregnated biological flocs to the MBR such that the PAC- impregnated biological flocs in the MBR adsorb to and remove a majority of the PFAS from the flow of wastewater and/or landfill leachate such that the MBR outputs a flow of treated wastewater and/or landfill leachate having a majority of the PFAS removed.
2. 2. The system of claim 1 in which the predetermined ratio of PAC to biomass is in the range of about 0.1:1 to about 5:1.
3. 3. The system of claim 1 in which the predetermined ratio of PAC to biomass is set to enhance at least one of: the removal of PFAS from the flow of wastewater and/or landfill leachate, membrane filtration, or nitrification and the removal of biodegradable organic matter as measured by biochemical oxygen demand (BOD).
4. 4. The system of claim 1 in which the MBR is configured to output a waste flow of PAC-impregnated biological flocs having PFAS adsorbed thereto.
5. 5. The system of claim 4 in which the waste flow of PAC-impregnated biological flocs having PFAS adsorbed thereto is set to control a biological population of microorganisms in mixed liquor in the MBR.
6. 6. The system of claim 4 in which a waste flow of PAC-impregnated biological flocs having PFAS adsorbed thereto is used to create a waste product.
7. 7. The system of claim 6 in which the waste product is directed to at least one of: a supercritical water oxidation (SCWO) process or a plasma gasification subsystem configured to destroy the waste product including the PAC-impregnated biological flocs having PFAS adsorbed thereto.
8. 8. The system of claim 1 in which the PAC-impregnated biological flocs increase treatment kinetics thereby reducing the required hydraulic retention time and size of the MBR.
9. 9. The system of claim 1 in which at least one impregnation tank is sized and configured to augment PAC impregnation into the biological flocs.
10. 10. The system of claim 1 in which blending intensity in the impregnation tank is configured to augment PAC impregnation into the biological flocs.
11. 11. The system of claim 1 in which the PAC-impregnated biological flocs enhance membrane filtration.
12. 12. A modified membrane bioreactor (MBR) system for removing per- and polyfluoroalkyl substances (PFAS) from a flow of wastewater and/or landfill leachate, the system comprising: an MBR configured to receive a flow of wastewater and/or landfill leachate having PFAS therein, the membrane bioreactor including biomass, a diffuser subsystem, and a membrane filter subsystem; an impregnation subsystem including at least one impregnation tank and at least one mixer, the impregnation subsystem configured to receive a flow of mixed liquor from the MBR and a predetermined amount granular activated carbon (GAC) reactivation waste product to maintain a predetermined ratio of GAC reactivation waste product to biomass in the MBR and configured to blend the biomass with the GAC reactivation waste product to form GAC reactivation waste product- impregnated biological flocs; and an outlet coupled to the at least one impregnation tank configured to output a flow of GAC reactivation waste product-impregnated biological flocs to the MBR such that the GAC reactivation waste product-impregnated biological flocs in the MBR adsorb to and remove a majority of the PFAS from the flow of wastewater and/or landfill leachate such that the MBR outputs a flow of treated wastewater and/or landfill leachate having a majority of the PFAS removed.
13. 13. The system of claim 12 in which the predetermined ratio of GAC reactivation waste product to biomass is in the range of about 0.1:1 to about 5:1.
14. 14. The system of claim 12 in which the predetermined ratio of GAC reactivation waste product to biomass is set to enhance at least one of: the removal of PFAS from the flow of wastewater and/or landfill leachate, membrane filtration, or nitrification and the removal of biodegradable organic matter as measured by biochemical oxygen demand (BOD).
15. 15. The system of claim 12 in which the MBR is configured to output a waste flow of GAC reactivation waste product-impregnated biological flocs having PFAS adsorbed thereto.
16. 16. The system of claim 15 in which the waste flow of GAC reactivation waste product having PFAS adsorbed thereto is set to control a biological population of microorganisms in mixed liquor in the MBR.
17. 17. The system of claim 15 in which the waste flow of GAC reactivation waste product-impregnated biological flocs having PFAS adsorbed thereto is used to create a waste product.
18. 18 The system of claim 17 in which the waste product is directed to at least one of: a supercritical water oxidation (SCWO) process or a plasma gasification subsystem configured to destroy the waste product including the GAC reactivation waste product-impregnated biological flocs and the PFAS adsorbed thereto.
19. 19. The system of claim 12 in which the GAC reactivation waste product- impregnated biological flocs increase treatment kinetics thereby reducing the required hydraulic retention time and size of the MBR.
20. 20. The system of claim 12 in which the at least one impregnation tank is sized and configured to augment GAC reactivation waste product impregnation into the biological flocs.

Description

A MODIFIED MEMBRANE BIOREACTOR (MBR) SYSTEM AND METHOD FOR REMOVING PER- AND POLYFLUOROALKYL SUBSTANCES (PFAS) FROM A FLOW OF WASTEWATER AND/OR LANDFILL LEACHATE RELATED APPLICATIONS This application claims benefit of and priority to U.S. Non-Provisional Application Serial No. 18/443,736 filed February 16, 2024 and U.S. Provisional Application Serial No. 63/517,950 filed August 7, 2023 under 35 U.S.C. §§119, 120, 363, 365, and 37 C.F.R. §1.55 and §1.78, which is incorporated by reference herein. FIELD OF THE INVENTION This invention relates to a modified membrane bioreactor (MBR) system and method for removing per- and polyfluoroalkyl substances (PFAS) from a flow of wastewater and/or landfill leachate. BACKGROUND OF THE INVENTION A membrane bioreactor (MBR) is a device or process which combines a microfiltration or ultrafiltration membrane with a bioreactor. The bioreactor includes a chamber which supports a biologically active environment where microorganisms, such as bacteria, protozoa, and the like, the “biomass”, grow and consume certain contaminants in waste water and/or landfill leachate. There are at least three types of bioreactors: 1) suspended growth bioreactors, where the biomass grows into biological flocs that are separated from the treated wastewater and/or landfill leachate by secondary clarification or membrane filtration, 2) attached growth (or biofilm) bioreactors, where the biomass grows attached to carriers, and 3) hybrid bioreactors, which combines suspended and attached growth. In MBRs, the membranes act as a solid-liquid separation device by retaining the biomass within the bioreactor before discharging the filtered, treated effluent to the environment. One key function of the membrane(s) is to separate solids from a liquid. The membrane(s) may be located internal or external to the bioreactor. Conventional powered activated carbon (PAC) may be used to adsorb and remove various decomposable organic contaminants from wastewater and/or landfill leachate. PAC treatment (PACT) may be combined with an MBR system (PACT-MBR) to enhance the biodegradation of slowly biodegradable organics and other decomposable organic contaminants. See e.g., Takase, O., Powered Activated Carbon Treatment Membrane Bioreactor (PACT MBR) using Ceramic Flat Sheet Membrane, Mieden Review, Series No. 1762019 No. 2, incorporated by reference herein. To date, the conventional PACT-MBR discussed above has not been optimized for maximum contaminant removal. These conventional systems typically add PAC to an MBR without optimizing the PAC particle size or ratio of the PAC to biomass. These conventional systems also do not impregnate the biological flocs with PAC. Utilizing PAC in an MBR can also be expensive because the PAC is a consumable additive that is removed along with the waste biological solids, and therefore must be added to the MBR on a regular basis, e.g., multiple times a week. Per- and polyfluoroalkyl substances (PFAS) are a class of man-made compounds that have been used to manufacture consumer products and industrial chemicals, including, inter alia, aqueous film forming foams (AFFFs). AFFFs have been the product of choice for firefighting at military and municipal fire training sites around the world. AFFFs have also been used extensively at oil and gas refineries for both fire training and firefighting exercises. AFFFs work by blanketing spilled oil/fuel, cooling the surface, and preventing re-ignition. PFAS in AFFFs have contaminated the groundwater, surface water, and wastewater and/or landfill leachate at many of these sites and refineries, including more than 100 U.S. Air Force bases. PFAS may be used as surface treatment/coatings in consumer products such as carpets, upholstery, stain resistant apparel, cookware, paper, packaging, and the like, and may also be found in chemicals used for chemical plating, electrolytes, lubricants, and the like, which may eventually end up in waste water and/or landfill leachate. PFAS are bio-accumulative in wildlife and humans because they typically remain in the body for extended periods of time. Laboratory PFAS exposure studies on animals have shown problems with growth and development, reproduction, and liver damage. In 2016, the U.S. Environmental Protection Agency (EP A) issued the following health advisories (HAs) for perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA): 0.07 pg/L for both the individual constituents and the sum of PFOS and PFOA concentrations, respectively. PFAS are very difficult to treat largely because they are extremely stable compounds which include carbon-fluorine bonds. Carbon-fluorine bonds are the strongest known covalent bonds in nature and are highly resistant to breakdown and therefore not considered decomposable. To date, conventional PACT-MBRs have not been used to remove PFAS from a flow of wastewater or landfill leachate because conventional PACT-MBRs are designed to enhance the biodegradation of slo