Method to Remove and Concentrate PFAS from Water

Abstract

Apparatus is disclosed for separating and concentrating one or more PFAS compounds from contaminated water or wastewater using a combination of membrane filtration and foam fractionation. Water is processed through a membrane filter to produce a permeate and a reject using a Reverse Osmosis or a Nanofiltration membrane where the permeate produced is suitable for potable applications and the reject produced is sent to a foam fractionator for further treatment. Wastewater is processed through a membrane filter to produce a permeate and a reject using an Ultrafiltration or Microfiltration membrane where the permeate produced is sent to a foam fractionator for further treatment and the reject is contained within a wastewater treatment plant as activated sludge. Membrane reject or permeate sent to a foam fractionator is then processed to remove any surface active contaminates (PFAS) by injecting air to generate a foam that can be collected and removed for storage producing a clean effluent that is suitable for environmental discharge and a foam concentrated with PFAS.

Claims

1. A method for the decontamination of water or wastewater containing one or more PFAS compounds using a primary membrane filter to produce a reject or permeate that passes through a secondary foam fractionator to produce a foam and an effluent.

2. The method of claim 1 wherein a Reverse Osmosis or Nanofiltration membrane produces a permeate that is suitable for discharge or consumption and a reject that is sent to a foam fractionator.

3. The method of claim 1 wherein an Ultrafiltration or Microfiltration membrane produces a permeate that is sent to a foam fractionator and a reject that is used as an activated sludge.

4. The method of claim 1 wherein the foam produced consists of PFAS compounds that can be further concentrated by processing the foam in additional foam fractionators.

5. The method of claim 1 wherein the effluent produced by the foam fractionator can be discharged to the environment or reused for other applications.

6. The method of claim 5 wherein the effluent can be further polished of residual contaminants by using adsorption media, electro-oxidation, electro-reduction, advanced oxidative processes, and plasma reactors to achieve a higher quality effluent.

Description

DRAWING DESCRIPTION

[0011] FIG. 1 shows a general arrangement of the treatment process claimed.

DETAILED DESCRIPTION OF THE INVENTION

[0012] When an environment is contaminated with PFAS, these compounds will migrate into sources of water and when ingested will accumulate in the body resulting in poor human health. In drinking water systems, the use of adsorption media is generally viewed to be the preferred method of PFAS removal and collection however this approach comes with a high operational cost due to frequent media changes and disposal costs (incineration). Membrane filtration (RO & NF) is also effective at separating PFAS from drinking water however the subsequent concentrate or reject waste streams ultimately lead to further contamination of the surrounding environment unless treated with additional equipment. Due to the hydrophilic/hydrophobic structure of PFAS molecules, foam fractionation is an effective means of collecting PFAS from water however it is not currently approved by the EPA as a means of treating PFAS from drinking water systems. When combining membrane technology with foam fractionation, PFAS levels in drinking water can be reduced to acceptable levels for human health, reject streams can be treated for PFAS removal without the use of consumable media effectively reducing environmental contamination and operational expenses. In areas where PFAS contamination requires higher levels of removal to meet discharge limits, an additional polishing step may be employed to further limit contamination by way of adsorption media, electro-oxidation, electro-reduction, advanced oxidative processes, and plasma reactors. Additional foam fractionators may also be used to achieve higher concentrations of PFAS effectively reducing the cost for disposal. PFAS remediation may also take place at a wastewater treatment plant where membrane technology produces a permeate that is sent to one or more foam fractionators for treatment prior to discharge or reuse.

SEQUENCE LISTING

[0013] Not Applicable