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Patent Issued for Process of Treating Water Using a Gas Permeable Membrane-Supported Biofilm Apparatus

July 8, 2014



By a News Reporter-Staff News Editor at Life Science Weekly -- A patent by the inventors Husain, Hidayat (Oakville, CA); Mazzaferro, Rocco (Waterdown, CA); Liu, Minggang (Burlington, CA); Wong, Richard (Thornhill, CA); Lossing, Heather (Hamilton, CA); Fan, Fengshen (Guelph, CA); Hong, Youngseck (Burlington, CA); Bayly, Reid (Toronto, CA), filed on November 9, 2012, was published online on June 24, 2014, according to news reporting originating from Alexandria, Virginia, by NewsRx correspondents (see also Zenon Technology Partnership).

Patent number 8758619 is assigned to Zenon Technology Partnership (Wilmington, DE).

The following quote was obtained by the news editors from the background information supplied by the inventors: "The following is not an admission that anything discussed herein is citable as prior art or part of the common general knowledge of persons skilled in the art.

"International (WIPO) publications WO/2001/066474, WO/2004/071973, WO/2005/016498, WO/2005/016826 and WO/2006/015496 describe various membrane supported biofilm devices or processes. These publications are incorporated herein in their entirety by this reference to them. These documents describe various apparatus or process details that may be useful in working with a membrane supported biofilm, although statements in these publications or in U.S. Application Ser. No. 60/913,195 do not limit or define the claims of this patent.

"International publication number WO/20018066174 describes an apparatus to transfer gas to or from a liquid having a flexible and oxygen permeable but liquid water impermeable membrane, a flexible and gas permeable spacer, an inlet conduit, an outlet conduit and a non-rigid restraint system. When used for treating wastewater, an aerobic biofilm is cultured adjacent the planar elements, an anoxic biofilm is cultivated adjacent the aerobic biofilm and the wastewater is maintained in an anaerobic state. A first reactor for treating wastewater has an anaerobic section, a plurality of gas transfer membrane modules, and an aerobic section. A biofilm is cultivated on the surface of the gas transfer membranes in fluid communication with the anaerobic section. Biological reduction of COD, BOD, nitrogen and phosphorous are achieved. In a second reactor, phosphorous is also removed chemically in a precipitation branch.

"International publication number WO/2004/071973 describes a membrane supported biofilm reactor with modules having fine, hollow fibres, for example, made from dense wall Poly methylpentene (PMP) used in tows or formed into a fabric. In one module, one or more sheets of the fabric are potted into a module to enable oxygen containing gas to be supplied to the lumens of the hollow fibres. Various reactors and processes, for example to treat wastewater, using such modules are described. Mechanical, chemical and biological methods are used to control the thickness of the biofilm.

"International publication number WO/2005/016498 describes a membrane module apparatus to transfer a gas to or from a liquid having a sheet with at least one gas transfer surface. The gas transfer surface is in flow communication with a header through a gas channel. The module may be used to support a biofilm on the gas transfer surface. A plurality of sheets or portions of sheets may be separated by spacers.

"International publication number WO/2005/016826 describes a membrane supported biofilm reactor with modules having fine, hollow fibres, for example, made from melt spun thermoplastic polymers treated after spinning to increase their permeability to oxygen, used, for example, in tows or formed into a fabric. In one module, one or more sheets of the fabric are potted into a module to enable oxygen containing gas to be supplied to the lumens of the hollow fibres. Various reactors and processes, for example to treat wastewater, using such modules are described. In one process, oxygen travels through fibers, optionally through an attached biofilm, to oxygenate surrounding water. Mechanical, chemical and biological methods, for example endogenous respiration, are used to control the thickness of the biofilm.

"International publication number WO/2006/015496 describes a module with hollow gas transfer fibers arranged in tows and potted into a module. The module may be used to treat wastewater by supplying hydrogen containing gas via the interior of the fibers to a biofilm present on an exterior surface of the fibers."

In addition to the background information obtained for this patent, NewsRx journalists also obtained the inventors' summary information for this patent: "The following summary is intended to introduce the reader to this disclosure, but does not limit or define any claimed invention.

"A membrane supported biofilm apparatus has a plurality of membranes that are permeable to gases but do not permit bulk liquid water flow. The membranes, and structures holding the membranes, are configured to provide an inner volume open to a supply of a gas. The membranes may be immersed in water to be treated with the inner volume separated from the water by the membrane walls. In operation, a gas fed to the inner volume permeates through the membrane walls to encourage the growth of a biofilm supported on the outer surface of the membrane walls. Organisms in the biofilm treat the water by way of one or more biological processes.

"A membrane supported biofilm apparatus may have a plurality of hollow fiber membranes. The membranes may have an outside diameter of about 200 microns or less. The membranes may be collected at a lower end in a header. Upper ends of the membranes may be held or floated near a water surface when the module is immersed in a tank with the header on or near the bottom of the tank. A spreader near the header may horizontally space some of the plurality of membranes from others of the plurality of membranes.

"Hollow fiber membranes for supporting a biofilm may be placed in a tank at a dry packing density in the range of about 0.5% to 4%. In a multi-stage system, a first module located in a first tank may have a lower dry fiber packing density than a second module located in a second tank downstream of the first tank. A biofilm supported on the membranes may occupy 40% or more, and up to about 70% or 80% of the reactor volume. A mixer and a solids removal port may be provided in association with the tank.

"A process for treating water using a membrane supported biofilm may be used to dentrify water or to reduce other oxidized contaminants such as nitrate, nitrite, perchlorate or arsenate. Hydrogen is introduced into the inner volume of the membranes and a carbon source is added to the water. A biofilm is grown on the membranes and has autotrophic organisms near the membrane and heterotrophic organisms near the water. Carbon dioxide may also be added to the inner volume.

"In another process, a membrane supported biofilm is to treat wastewater having over 2000 mg/L CODt. A biomass concentration of at least 20 g/L and up to about 40 g/L is maintained. A biofilm is maintained having a surface area of at least about 1000 square meters per cubic meter of water being treated in the reactor. The biofilm may occupy between about 50% and 80% of the volume of the tank.

"A hybrid bioreactor and process may have a suspended biomass and a membrane supported biofilm. The reactor and process may be used to treat wastewater. The reactor may have a solids separation device downstream of a tank containing the biofilm and a recycle of separated solids to the tank. The recycle may pass through an anoxic stage before returning to the tank. The tank may have a mixer to keep the suspended biomass in suspension. The tank may have an aerator, which may also function as a mixer, to supply a gas to the suspended biomass."

URL and more information on this patent, see: Husain, Hidayat; Mazzaferro, Rocco; Liu, Minggang; Wong, Richard; Lossing, Heather; Fan, Fengshen; Hong, Youngseck; Bayly, Reid. Process of Treating Water Using a Gas Permeable Membrane-Supported Biofilm Apparatus. U.S. Patent Number 8758619, filed November 9, 2012, and published online on June 24, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8758619.PN.&OS=PN/8758619RS=PN/8758619

Keywords for this news article include: Chalcogens, Zenon Technology Partnership.

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Source: Life Science Weekly


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