626 results about "Membrane fouling" patented technology

A process for removing soluble and insoluble inorganic, organic, and microbiological contaminants from a fluid stream employing a pretreatment module, a post-treatment module, a recycle stream module or any combination thereof, and a membrane module, is provided. The process provided reduces the problems associated with membrane fouling and increases contaminant removal capacity.

A reverse osmosis composite membrane that has a high salt rejection, a high water permeability, and a high fouling tolerance, and permits practical desalination at a relatively low pressure is provided by coating the surface of a reverse osmosis membrane of aromatic polyamide with polyvinyl alcohol (PVA), for example, and controlling the surface zeta potential of the separation layer within±10 mV at pH 6. This reverse osmosis composite membrane is electrically neutral and controls the electrical adsorption of membrane-fouling substances having a charge group present in water. Therefore, a high separation property can be maintained without fouling the membrane even if water containing a surfactant or a transition metal component is supplied as raw water.

An inclined plate coupled membrane bioreactor for treating feed water having excessive level of nutrients in particular chemical oxygen demand and total nitrogen and suspended solids has an aerobic bioreactor for nitrification and aerobic biodegradation in which membranes are submerged for permeate extraction, and an anoxic bioreactor for denitrification within which the inclined plates are outfitted to confine as much anoxic sludge as possible. An air oxygenating and an air scouring are continuously provided to the aerobic bioreactor to maintain a desired aerobic environment and to mitigate membrane fouling while an intermittent air blowing is provided to the anoxic bioreactor to blow out gaseous content generated through denitrification and to rectify the uniformed flow along the inclined plates. The aerobic sludge is recycled to the lower compartment of anoxic bioreactor and the supernatant of anoxic bioreactor is collected as weir effluent and delivered to the downstream aerobic bioreactor. Permeate is intermittently extracted from the membranes by a suction pump. There is no excess sludge withdrawn from the inclined plate coupled membrane bioreactor throughout the experiment.

The fouling state of a polymeric membrane within the high pressure housing of a spiral wound or a hollow fiber membrane module is determined. An ultra sonic transducer positioned with its emitting face in physical engagement with the outer surface of the housing is pulse energized by a pulser/receiver device. A membrane echo signal is detected by a receiver of the pulser/receiver device. A reference echo signal indicative of a fouled or an unfouled state of the membrane is compared to the echo signal to determine the membrane fouling state. The echo to reference comparing step can be based upon comparing amplitude domain signals, comparing time-domain signals, comparing combinations of amplitude domain and time-domain signals, and comparing transformations of amplitude domain and time-domain signals. A clean or a fouled reference echo can be provided from a clean or a fouled membrane and then stored for use during a liquid separation process, or a clean reference echo signal can be obtained on-line from a second transducer whose echo signal is derived from an area of the membrane known to remain relatively unfouled during the liquid separation process, or a clean or fouled reference echo signal can be provided for later use during a cleaning process or during a liquid separation process. Multiple transducers and a switching network can sample the fouling state at different positions within the membrane module.

A method of conditioning mixed liquor in a membrane biological reactor comprising adding to the mixed liquor an effective coagulating and flocculating amount of one or more water soluble cationic, amphoteric or zwitterionic polymers, or combination thereof and methods of reducing membrane fouling, enhancing membrane flux and reducing sludge production.

Submerged gas diffuser assemblies configured to aerate liquid suspensions in reservoirs or deep shafts with enhanced aeration contact patterns and adjustable aeration rates. Aeration contact patterns and rates are varied by the adjusting the spatial configuration of gas permeable membranes, altering the fluid flow patterns around the membranes, manipulating trans-membrane pressures across membranes, varying the sequence of aeration of liquid within the fluid flow patterns, expanding the membrane surface area, and/or by selectively occluding certain portions of membrane surface area of the membrane assemblies. The membrane assemblies are designed to prevent, control, or mitigate membrane fouling and hydro lockup.

The present invention includes methods and compositions for liquid separation and water purification. The present invention includes a purification membrane having a polymer matrix purification membrane that has been treated with hydroquinone, catechol, and/or dopamine coated membrane with a high water flux.

System and method for conditioning water. In one embodiment, a softening membrane selectively rejects hardness ions in a supply of water. In another embodiment, the softening membrane is used in conjunction with a purification device configured to remove impurities from a portion of output flow of softened permeate water. In a third embodiment, the softening membrane is used in conjunction with a conditioning agent dosing unit configured to supply at least one conditioning agent to an input flow of water entering the membrane to prevent membrane fouling. In still another embodiment, a water quality monitoring unit is configured to monitor water quality of the output flow of softened permeate water and a portion of concentrate water recycled back through the softening membrane.

Water treatment systems and methods are provided to minimize membrane fouling and the required maintenance that results therefrom. A water treatment system includes a pressure vessel with a plurality of spaced-apart membranes disposed therein, and an impeller or other means for circulating feed water through the interior of the vessel and past the membranes. Antifouling particles (such as diatomaceous earth or activated carbon) and/or pellets can be added to the feed water inhibit membrane fouling and extend the useful life of the membranes.

The present invention provides a fluorescence-based modeling method that is capable of capturing the dynamic changes of different membrane foulant fractions that occur in fluid filtration operations. Principal component analysis is utilized to de-convolute spectral information captured within fluorescence EEMs into principal component scores that are related to different known foulant groups. The principal component scores are then used as states within a system of differential equations representing approximate mass balances of the main foulant groups to obtain a dynamic forecasting of membrane fouling. Based on the fouling dynamics forecasted by this modeling method, an optimization strategy can be developed for estimating the optimal membrane back-washing scenario for minimizing energy consumption while maximizing clean fluid production.

A fluid separation method for performing fluid analysis of an unfiltered fluid. The fluid separation method includes providing a structure with a fluid analyzer and a power supply. Using a substrate for receiving a fluid flow stream of a multiphase mixture through a fluid sample inlet, wherein the substrate interconnects with the structure. Providing a membrane disposed across the fluid sample inlet for separating a fluid of interest from the multiphase mixture, wherein the fluid flow stream of the multiphase mixture has a shear rate that prevents a fouling of the membrane. Finally, the fluid separation method includes the substrate having fabricated channels, such that the fabricated channels are arranged substantially tangent to the fluid stream downstream of the porous membrane.

A spiral wound module assembly comprising: a permeate collection tube, at least one membrane envelope wound about the permeate collection tube, an outer module housing, and at least one acoustic transducer located adjacent to the permeate collection tube. Several embodiments are disclosed including a stand-alone probe adapted for insertion into the permeate collection tube. In several other embodiments, one or more transducers are secured to the inner surface of the permeate collection tube. The invention further includes a method of measuring membrane fouling within a spiral wound module comprising the steps of: a) transmitting an acoustic signal from a location adjacent to the permeate collection tube; b) receiving an echo signal resulting from the transmitted acoustic signal reflecting from an interface within the module; c) providing a reference signal corresponding to a known state of membrane fouling; d) comparing the echo signal to the reference signal; and e) determining a state of membrane fouling based upon the comparison of the echo signal and reference signal.

A pre-treatment method for cleaning and maintaining reverse osmosis membrane filters by injecting sulfurous acid into waters with suspended solids in a liquid fraction to be filtered to form sulfurous acid (H₂SO₃) to acid leach heavy metals into the liquid fraction, reduce alkalinity and mineral scaling, add sufficient SO₂ as a biocide to attack bacteria and other micro organisms to prevent membrane fouling, reduce iron to prevent iron deposit build-up, scavenge and remove dissolved oxygen prior to filtration to prevent membrane oxidation, and then sequentially filtering the acidified water through membrane filters to create a metal free permeate and a brine retentate, which can be pH adjusted to remove the heavy metals as metal hydroxide precipitates.

It is an object of the present invention to provide a membrane separation apparatus and a membrane separation process that are unlikely to cause membrane fouling and plugging, capable of achieving membrane separation even with relatively low flow rate of water, have an excellent membrane packing density, and are unlikely to cause deposition of foreign components in the apparatus. In order to achieve the above object, according to the present invention, vessel-type inner casings are disposed in a pressure vessel along the longitudinal axis thereof, in which the pressure vessel has a water inlet at a first end and a concentrate outlet at a second end. A flow-regulating plate is disposed on the side of the water inlet of the pressure vessel. Stacks of membrane separation units are respectively disposed in the inner casings, and spacers are disposed between the adjacent membrane separation elements. The spacers also serve as sealing members. Each stack of the membrane separation units and the spacers together define a through-hole extending from a first side to a second side, of the stack of the membrane separation elements. The inner casings have permeate discharge passages along the longitudinal axis thereof. The permeate discharge passages are communicated with the through-hole of each stack of the membrane separation elements. Water that has been fed into the pressure vessel via the flow-regulating plate permeates through the membrane separation elements and is discharged to the outside via the through-holes and the permeate discharge passages.

The invention relates to a polyvinylidene fluoride/organic clay nano composite ultralow pressure ultrafiltration membrane and a preparation method thereof, and to a nano composite membrane and a preparation method thereof. The invention resolves the problem that the existing membrane material has a bad hydrophilicity and a low surface energy and is easily be polluted, and the existing modified method has the disadvantage that it can not run under ultralow pressure and the running cost is high. It is composed of 20-50 shares by weight of PVDF, 0.1-20 shares by weight of organic clay, 10-1000 shares by weight of disperse medium, 10-50 shares by weight of organic addition agent and 0.1-30 shares by weight of inorganic additive. The invention adds the organic clay, inorganic additive, organic addition agent and PVDF in turns into the disperse medium to get the casting film liquor after 3-48 hours dissolution and 5-24 hours stewing deaeration; plate membrane, tubular type membrane, hollow fibre membrane, and comparable membrane module can be prepared. The invention can change the hydrophilicity of the composite membrane, resolve the pollution of exiting membrane effectively, increase the water flux and retain ratio, extend the washing period, raise the treating capacity, and realize the large scale use and run in ultralow pressure.

The invention discloses a method and a device for separating electric field-separation membrane coupling, which are characterized in that: separation membranes with different natures are parallelly arranged, and the outmost sides are provided with electrodes so as to form a plurality of layers of runners formed between the separation membranes and between the separation membranes and the electrodes; and fluid to be separated flows through the runners in a staggered way, and a DC electric field is applied in the direction vertical to the runners, so that electriferous molecules or microparticles generate deviation or dialytic electrophoretic behavior under the condition of the electric field, and an aperture screening effect of the separation membranes is combined so as to realize the process of quick and high-efficiency separation. The process can be performed only under the driving of the electric field, and also can be performed under the driving of the electric field and pressure. Compared with the conventional membrane process and electrophoresis process, the method and the device can greatly improve concentration and separation efficiency, improve separation factors, realize the separation which cannot be realized by the conventional membrane process, obviously reduce membrane fouling and improve the service life of the membranes.

A method for cleaning and maintaining reverse osmosis membrane filters by injecting sulfurous acid into water to form sulfurous acid (H₂SO₃), and then sequentially filtering the acidified water through membrane filters to reduce alkalinity and mineral scaling, add sufficient SO₂ as a biocide to attack bacteria and other micro organisms to prevent membrane fouling, reduce iron to prevent iron deposit build-up, scavenge and remove dissolved oxygen prior to filtration to prevent membrane oxidation, and prevent concentrated salts within the retentate from precipitating out of solution during transport for land application.

The invention discloses an electrodeionization (EDI) method and system dispensing with ion exchange membranes. The system is characterized in that porous water distribution plates, top electrodes, ion exchange resins, bottom electrodes and porous floating blocks with density less than that of water are placed in an insulating cavity from top to bottom in sequence; a top cover and the upper ends of cylindrical shells are sealed by upper seal rings; a bottom cover and the lower ends of the cylindrical shells are sealed by lower seal rings; the porous water distribution plates and the top electrodes are fixed between the top cover and the end faces of the cylindrical shells; the bottom electrodes are fixed on the porous floating blocks; intermediate seal rings are installed between the porous floating blocks and the cylindrical shells; and the top and bottom electrodes are respectively connected with a high-voltage direct current power supply. The method and the system have the following beneficial effect: the problems of membrane pollution, concentration polarization, scaling, hydroxide precipitates formed on the membrane surfaces when the heavy metal wastewater containing Cu<2+>, Ni<2+> and other ions are treated because the ion exchange membranes are adopted for EDI are solved. The method and the system are suitable for preparation of highly pure water, purification of electroplating rinse wastewater containing heavy metal ions and treatment of water and wastewater aiming at removing the ionic impurities.

The invention provides a method of a pulse-jet membrane bioreactor and a device for realizing the method. The method adopts a jet aerator to replace a traditional blower to realize the cross-flow scouring effect of membrane components; wherein, circulating fluid flows through the jet aerator at high speed; air enters the jet aerator in a pulse way by a valve controlled by PLC and jets at the bottom through a gas spreading distributor; the PLC system regulates the cross-flow state of gas-liquid two-phase flow on the membrane surface by changing circulation flow rate and pulse frequency, so as to improve the scouring effect of the air to the membrane surface, to further control membrane pollution, to improve the energy utilization efficiency of a circulating pump and to reserve energy. The use of the jet aerator also increases the utilization efficiency of oxygen and improves sludge degradation effect. The device has the advantages of low operation energy consumption and low operation noise, slight membrane pollution, less early investment in equipment, simple structure of the device, small occupation area, simple and convenient operation and convenience in automatic running and control.

The invention provides a pollution resistant membrane module which is a flat membrane module. The membrane module comprises a frame and two filter membranes, wherein the two filter membranes respectively cover the two sides of the frame; a liquid flow channel is formed between the two filter membranes; a water outlet is arranged at one end of the frame; at least a conducting coil pipe vertical to the filter membranes is arranged between the two filter membranes; magnetic chips are arranged in the positions corresponding to the coil bodies on the filter membranes; and the orientations of the south and north poles of the two magnetic chips in the same positions on the two filter membranes are identical. The pollution resistant membrane module has the following beneficial effects: when being electrified, the conducting coils in the pollution resistant membrane module generate south and north poles and generate attractive forces or repulsive forces towards the filter membranes or supporting filter plates which are provided with the magnetic chips with south and north poles; the directions of the south and north poles of the conducting coils are changed by changing the current directions, so that the filter membranes can be continuously shaken to shake off the pollutants, thus alleviating membrane pollution and prolonging the service lives of the membranes; and less electricity is used, so the aeration energy consumption can be reduced and the operation cost can be lowered.

Disclosed is a method for preventing osmotic membrane fouling comprising treating reverse osmotic feed water and membranes with chlorine dioxide at an extremely low concentration, e.g., as low as one part per billion in the feed water. The effective range may be in the range of 1-900 parts per billion. Also disclosed is a membrane separation system in which fouling is prevented using ultraviolet, pH acid adjustment or an electrochemical generator to produce the chlorine dioxide.

The invention discloses a membrane bio-reactor (MBR) used for treating preserved szechuan pickle wastewater and reinforcing biological phosphorous and nitrogen removal. An integrated reactor is formed by an A<2>/O process, a biological membrane process and the MBR. The MBR comprises an anaerobic tank, an anoxic tank, an aerobic tank, a feeding system, an aerating system, a drainage system and automatic control equipment, wherein semi-soft biological membrane fillers are put in the anaerobic tank, the anoxic tank and the aerobic tank; a membrane component is put in the aerobic tank, and a membrane separation region is not independently arranged. The reactor has the advantages that anaerobic phosphorus release and phosphorus accumulation in the aerobic tank are carried out via the sludge on the biological fillers in the anaerobic tank, thus increasing the total removal rate of phosphorus in the sewage; organic matters undergo hydrolytic acidification and organic nitrogen is aminated after the preserved szechuan pickle wastewater passes through the anaerobic tank; nitrification liquor in the aerobic tank flows back to the anoxic tank to form denitrification in the anoxic tank. The MBR has a simple structure and high pollutant treatment efficiency, is light in membrane pollution, and can simultaneously treat the pollutants such as organic matters, total nitrogen, total phosphorus, SS and the like of high salinity wastewater.

The invention discloses a modified polyvinylidene fluoride (PVDF) hollow fibrous membrane and a preparation method thereof. The modified PVDF hollow fibrous membrane comprises a PVDF hollow fibrous micro filter membrane and a new dynamic secondary TiO2 nano particles perfillmimg layer on the surface of the filter membrane. The preparation method of the fibrous membrane comprises the steps of preprocessing the PVDF hollow fibrous micro filter membrane and preparing a TiO2 dynamic modified membrane. In the invention, TiO2 nano particles are physically coated on the surface of the PVDF hollow fibrous micro filter membrane to modify a dynamic membrane, so that the hydrophilism and the contamination resistance of the PVDF hollow fibrous micro filter membrane are improved; and the dynamic membrane is used in a membrane bioreactor, and a result shows that the dynamic membrane is lower in the growth ratio of membrane contamination. Furthermore, the preparation method of the modified PVDF hollow fibrous micro filter membrane is simple, effective and practical.

The present invention relates to an apparatus for monitoring the progress of membrane fouling that occurs on pores as well as on the surface of a membrane by means of variations of zeta potential (zeta) of a hollow-fiber membrane according to time passage of filtration of a suspension, wherein colloid particles, biopolymers and other inorganic particles are dispersed, and the method thereof. Moreover, the present invention also relates to a method to identify the effect of concentration polarization layer and cake layer which can vary according to the axial position of a hollow-fiber and the developing progress of a membrane fouling by measuring the position-dependent zeta potential of the hollow-fiber membrane.