Methods and systems for removing trichloroethane, trichloroethene, and 1,4-dioxane from contaminated water and wastewater

A system for removing trichloroethane (TCA), trichloroethene (TCE), and 1,4-dioxane (1,4-D) contaminants from a fluid, comprising a first reactor and a second reactor in fluid connection, wherein:

• the first reactor comprises:
• a catalyst-precursor medium, the catalyst precursor medium comprising a precious metal salt and a liquid solvent;
• a hydrogen (H2) gas source;
• and
• a first nonporous membrane comprising a gas-phase side and a liquid-phase side, wherein:
• the liquid-phase side of the first nonporous membrane is in fluid contact with the catalyst-precursor medium;
• the H2 gas source delivers hydrogen to the gas-phase side of the first nonporous membrane thereby reducing the precious metal salt in the catalyst-precursor medium into the elemental form of the precious metal;
• and
• the elemental form of the precious metal deposes on the liquid-phase side of the first nonporous membrane;
• and
• the second reactor comprises:
• a microorganism-enrichment medium comprising ethane and/or 1,4-D;
• an inoculant comprising microorganisms selected from at least one family selected from the group consisting of Rhodocvclaceae, Pseudonocardiaceae, Brandyrhizobiaceae, and Chitinophagaceae;
• an oxygen (O2) gas source;
• and
• a second nonporous membrane comprising gas-phase side and a liquid-phase side, wherein:
• the liquid-phase side of the second nonporous membrane is in fluid contact with the microorganism-enrichment medium;
• the O2 gas source delivers oxygen to the gas-phase side of the second nonporous membrane;
• and
• microorganisms in the inoculant produces a biofilm on the liquid-phase side of the nonporous membrane in the presence of the microorganism-enrichment medium.

A method of producing a synergistic system for reducing trichloroethane (TCA) and trichloroethene (TCE);

• and degrading 1,4-dioxane (1,4-D), the method comprising:
• providing a first nonporous membrane, the first nonporous membrane comprising a gas-phase side and a liquid-phase side;
• contacting the liquid-phase side of the first nonporous membrane with a catalyst-precursor medium, the catalyst-precursor medium comprising a precious metal salt and a solvent;
• contacting the gas-phase side of the first nonporous membrane with hydrogen (H2) gas at a sufficient partial pressure to convert at least 90% of the precious metal salt in the precious metal medium to elemental form, wherein the elemental form of the precious metal is in the form of a nanoparticles with diameters of 5-40 nm and the precious metal nanoparticles are deposed on the liquid-phase side of the first nonporous membrane to form a catalyst film;
• providing a second nonporous membrane, wherein the second nonporous membrane comprises a gas-phase side and a liquid-phase side;
• submerging the second nonporous membrane with a microorganism-enrichment medium comprising dissolved ethane and/or 1,4-D;
• contacting an inoculant with the liquid-phase side of the second nonporous membrane, wherein the inoculant comprises microorganisms selected from at least one family selected from the group consisting of Rhodocvclaceae, Pseudonocardiaceae, Brandyrhizobiaceae, and Chitinophagaceae;
• and
• pressurizing the gas-phase side of the second nonporous membrane with oxygen (O2) gas at a desired partial pressure thereby forming a biofilm comprising microorganisms capable of degrading ethane and 1,4-D on the liquid-phase side of the second nonporous membrane,
• wherein the catalyst film reduces TCA and TCE to produce ethane and 1,4-D and the biofilm degrades the ethane and 1,4-D.