HU0402564A2 - membrane process to apply water soluble polymers, biological reactor - Google Patents

membrane process to apply water soluble polymers, biological reactor Download PDF

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Publication number
HU0402564A2
HU0402564A2 HU0402564A HU0402564A HU0402564A2 HU 0402564 A2 HU0402564 A2 HU 0402564A2 HU 0402564 A HU0402564 A HU 0402564A HU 0402564 A HU0402564 A HU 0402564A HU 0402564 A2 HU0402564 A2 HU 0402564A2
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Hungary
Prior art keywords
polymer
liquid mixture
membrane
cationic
water
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HU0402564A
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Hungarian (hu)
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HU228884B1 (en
Inventor
John H. Collins
Kristine S. Salmen
Deepak A. Musale
Seong-Hoon Yoon
William J. Ward
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Nalco Company
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Priority to US10/035,785 priority Critical patent/US6723245B1/en
Application filed by Nalco Company filed Critical Nalco Company
Priority to PCT/US2003/000301 priority patent/WO2003057351A1/en
Publication of HU0402564A2 publication Critical patent/HU0402564A2/en
Publication of HU228884B1 publication Critical patent/HU228884B1/en

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    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00Biological treatment of water, waste water, or sewage
    • C02F3/02Aerobic processes
    • C02F3/12Activated sludge processes
    • C02F3/1236Particular type of activated sludge installations
    • C02F3/1268Membrane bioreactor systems
    • C02F3/1273Submerged membrane bioreactors
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D61/00Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis, ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/025Reverse osmosis; Hyperfiltration
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D61/00Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis, ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/027Nanofiltration
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D61/00Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis, ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/04Feed pretreatment
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D61/00Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis, ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14Ultrafiltration; Microfiltration
    • B01D61/145Ultrafiltration
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D61/00Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis, ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14Ultrafiltration; Microfiltration
    • B01D61/147Microfiltration
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D61/00Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis, ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14Ultrafiltration; Microfiltration
    • B01D61/16Feed pretreatment
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2311/00Details relating to membrane separation process operations and control
    • B01D2311/04Specific process operations in the feed stream; Feed pretreatment
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2315/00Details relating to the membrane module operation
    • B01D2315/06Submerged-type; Immersion type
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/52Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/54Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
    • C02F1/56Macromolecular compounds
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00Technologies for wastewater treatment
    • Y02W10/10Biological treatment of water, waste water, or sewage
    • Y02W10/15Aerobic processes
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00Technologies for wastewater treatment
    • Y02W10/40Valorisation of by-products of wastewater, sewage or sludge processing
    • Y02W10/45Obtention of bio-polymers

Abstract

The present invention relates to a method for conditioning a liquid mixture in a membrane biology reactor comprising a membrane module (2) immersed in an aeration vessel (1). The process is characterized in that an effective coagulating and flocculating amount of the liquid mixture is provided by a less soluble, cationic, amphoteric or zwitterionic polymer or a combination thereof. The invention also provides methods for reducing further membrane sealing, increasing membrane flux, and reducing sludge formation. HE

Description

COPIES

P0402564

EXTRACT

PROCEDURE FOR THE USE OF WATER SOLUBLE POLYMERS

MEMBRANE BIOLOGICAL REACTOR

The present invention relates to a method for conditioning a liquid mixture in a membrane biological reactor comprising 2 membrane modules immersed in an aeration tank. The process is characterized in that one or more soluble, cationic, amphoteric or zwitterionic polymers or combinations thereof are effective coagulating and flocculating amounts of the liquid mixture. The invention also relates to methods for reducing membrane obstruction, increasing membrane flux, and reducing sludge formation.

700 135 / DE

DISCLOSURE

COPIES

SBG & Κ »

Patent Attorney's Office H-1062 Budapest, Andrássy út 113, Phone: 461-1000, Fax: 461-1099

P0402564

PROCEDURE FOR THE USE OF WATER SOLUBLE POLYMERS

MEMBRANE BIOLOGICAL REACTOR

FIELD OF THE INVENTION

The present invention relates to the use of water-soluble cationic, amphoteric or zwitterionic polymers to condition a liquid mixture in membrane biological reactors to reduce clogging and increase fluid flow through the membrane. The present invention further relates to a method for using polymers to control sludge formation in a bioreactor.

BACKGROUND OF THE INVENTION

The biological treatment of wastewater is well known for the removal of dissolved organic matter, which is widely used in both urban and industrial plants. This aerobic biological process is generally known as an activated sludge process in which the microorganisms consume organic compounds and thus multiply. The process necessarily involves microorganisms or "biomass settling to separate water and complete biological oxygen demand (BOD) and all suspended solids (total suspended solids, TSS) in the effluent. Sedimentation is typically carried out in a cleaning unit. Thus, the biological process is limited by the need to produce biomass with good sedimentation properties. These conditions are extremely difficult to meet during batch periods of high organic matter content and the appearance of toxic impurities in biomass.

Typically, the activated sludge treatment converts the organic material into sludge with a 0.5 kg sludge / kg COD (chemical oxygen demand) conversion to form a significant amount of excess sludge. The cost of treating excess sludge is estimated to be 40-60% of the total cost of the wastewater treatment plant. In addition, the conventional removal of sludge by the land reclamation process can cause secondary pollution problems. Therefore, there is an increasing interest in processes that reduce the volume and weight of excess sludge.

The use of membranes for treating wastewater is well known in biological reactors, but they are not widely used. In these systems, ultrafiltration (UF), microfiltration (MF) or nanofiltration (NF) membranes replace the settling for solid-liquid separation. The membrane can be mounted in the bioreactor tank or in an adjacent container where the liquid mixture is continuously pumped from the bioreactor tank and back, so that the amount of suspended solids (TSS) in the effluent is much lower, typically less than 5 mg / l. 20-50 mg / l measured in the liquid flowing out of the cleaner. It is particularly important that the MBRs (membrane biological reactors, membrane biological reactors) release the biological process from the need for biomass sedimentation, as the membranes filter out the biomass from the water. This allows biological processes to be carried out under conditions that cannot be standard in conventional systems3; these conditions are: 1) high, 10-30 g / 1 MLSS (bacterial concentration), 2) increased sludge residence time, 3) short hydraulic residence time. Under these conditions, large amounts of sludge can be generated in conventional systems and this can be poorly deposited.

The advantage of using MBR is the small sludge production, the complete removal of solids from the effluent, the disinfection of the effluent, the combined COD, solids and nutrient removal in one unit, the possibility of using high bacterial concentration, eliminating the formation of large sludge and small space requirements. The disadvantages include aeration restrictions, membrane sealing, and membrane costs.

The membrane costs are directly proportional to the membrane area required for the flow of a given volume on the membrane, i.e. the flux. Flux is expressed in liters / h / m 2 (LMH). Typical fluxes are approx. They range from 10 to 50 LMH. These relatively low fluxes, which are largely caused by clogging of the membranes, slowed down the spread of MBR systems in wastewater treatment.

The MBR membrane is in contact with the so-called "liquid mixture", which is water, dissolved solids such as proteins, polysaccharides, suspended solids such as colloidal and particulate matter, bacterial aggregates, or "flakes, free bacteria, protozoa, various dissolved metabolites products and cellular components. During operation, the material present in the colloid and particulate matter and the dissolved organic material settle on the membrane surface. The colloidal particles form a layer on the surface of the membrane, called cake layer. The formation of the pie is particularly problematic in the case of MBRs used in dead end mode, where there is no cross current, i.e., tangential flow to the membrane. Depending on the porosity of the pie, the hydraulic resistance increases and the flux decreases.

In addition to the sheet formed on the membrane, small particles can also clog the pores of the membrane and this clogging may not be translated. In contrast to the conventional sludge process, the flake (particle) size is much smaller in the typical MBR units. Since the MBR pore size is approx. 0.04 to 0.4 microns, smaller particles may clog pores. Clogging the pores increases resistance and reduces flux.

Therefore, better methods of conditioning the liquid mixture in MBR units are required to increase the flux and to reduce membrane clogging.

Summary of the Invention

Polymeric water-soluble coagulants and flocculating agents have not been used in MBR units, since it is generally believed that excess polymer will break the membrane surface and greatly reduce membrane flux.

However, it has been discovered that the use of certain water-soluble cationic, amphoteric and zwitterionic polymers in the MBR for coagulating and flocculating biomass in the liquid mixture

and substantially reducing membrane clogging to precipitate the soluble biopolymer and increase membrane flux by up to 500% while substantially leaving no excess polymer in the treated wastewater at an effective dose. This increase in membrane flux allows the use of smaller systems while reducing investment costs or otherwise increases the volume flow of treated wastewater from an existing system while reducing operating costs.

Accordingly, the present invention relates to a method for conditioning the liquid mixture in a membrane biological reactor characterized in that an effective coagulating and flocculating amount of one or more water-soluble, cationic, amphoteric or zwitterionic polymers or combinations thereof are added to the liquid mixture.

One embodiment of the present invention is a method for treating waste water in a membrane biological reactor, wherein the microorganisms consume organic material in the waste water and thereby produce a liquid mixture containing water, microorganisms and solids and suspended solids, the process being characterized by:

i) adding to the liquid mixture an effective coagulating and flocculating amount of one or more cationic, amphoteric or zwitterionic polymers, or mixtures thereof, to form a mixture comprising water, microorganisms and coagulated or flocculated solid; and

ü) the purified water is separated from microorganisms and coagulated and flocculated solids by membrane filtration.

Another embodiment of the invention is a method for preventing filter membrane clogging in a membrane biological reactor, where microorganisms consume organic material in waste water, in a liquid mixture containing water, microorganisms and soluble, colloidal and suspended solids, and wherein the purified water is liquid. the process is characterized in that one or more cationic, amphoteric or zwitterionic polymers or combinations thereof are added to the liquid mixture in an amount sufficient to prevent membrane clogging.

Another embodiment of the invention is a method for increasing flux on a filter membrane in a membrane biological reactor, wherein the microorganisms consume organic material in the wastewater, in a liquid mixture containing water, microorganisms and soluble, colloidal and suspended solids, and wherein the purified water is liquid. the process is characterized in that one or more cationic, amphoteric or zwitterionic polymers or combinations thereof are added to the liquid mixture in an amount effective to increase the flux.

Another embodiment of the invention is a method of reducing sludge formation in a membrane biological reactor, wherein the microorganisms consume organic material in the wastewater, and thus form a liquid mixture comprising water, microorganisms and dissolved, colloidal and suspended solids, and wherein the purified water is separated from the liquid mixture 7 by filtration through a membrane

1) adding to the liquid mixture an effective coagulating and flocculating amount of one or more cationic, amphoteric or zwitterionic polymers or combinations thereof; and

2) increase the concentration of microorganisms in the liquid mixture.

Another embodiment of the invention is a method of reducing sludge formation in a membrane biological reactor, wherein the microorganisms consume organic material in the wastewater, and thus form a liquid mixture comprising water, microorganisms and dissolved, colloidal and suspended solids, and wherein the purified water is separated from the liquid mixture by filtration on a membrane, the process being characterized by

1) adding to the liquid mixture an effective coagulating and flocculating amount of one or more cationic, amphoteric or zwitterionic polymers or combinations thereof; and

2) increase the duration of contact of the microorganisms with the wastewater.

A brief description of the figures

Fig. 1 is a schematic diagram of a membrane bioreactor system for biological treatment of a typical wastewater system, comprising an aeration tank 1, an immersed membrane module 2, a pump 3, an aeration device 4 for membrane cleaning, an aeration device 5 for bioreculation, and optionally a 6 sludge breakers.

Figure 2 shows sludge generation curves calculated by simultaneously solving equations (1) and (2) below. The parameters and constants used in the calculation are summarized in Tables 1 and 2. The rate of sludge formation can be calculated from the slope of the tangent of a suspended solids (MLSS) for a given liquid mixture (e.g. 18,000 mg / l). Therefore, "zero slope means" there is no mud formation.

In Figure 2, 1) the slope of the tangent decreases with the increase of the hydraulic residence time (HRT) while the MLSS is constant and 2) decreases with the increase of the MLSS while the HRT is constant. In the first case, when the MLSS is constant, for example, 14,000 mg / L, no excess sludge occurs when HRT increases to 12 hours. In the second case, where the HRT is constant, for example 10 hours, no sludge is generated if it is

MLSS grows to 17,000 xng / l.

The sludge residence time (SRT) is calculated by dividing the total amount of sludge in the bioreactor (kg) by the sludge removal rate (kg / day). Therefore, SRT increases when the excess sludge production is lower, until it becomes "infinite without producing excess sludge.

In biological wastewater treatment processes, the microorganisms in the bioreactor grow when the organic matter in the wastewater is consumed. In addition, the microorganisms are breathing endogenously with which they are consumed. These phenomena are described in equation (1), where the growth of microbes is expressed by the Monod equation, and the endogenous breathing is removed from it, which is taken into account by the first order kinetic equation (kax) of the equation side of the side.

(1)

X - kjX dt K s + S e

Here, Pm is the maximum specific growth rate (day -1 ), Ks is the half saturation constant (mgl -1 ), meaning the endogenous decomposition constant (day -1 ), Se is the substrate concentration in the liquid mixture (mgl -1) ), x stands for MLSS (mgl -1 ), and t is time (day).

While the microorganisms proliferate, most of the substrate (organic pollutants in the inlet fluid) is consumed and all are discharged with the effluent. This equilibrium can be described by equation (2), where the right front member expresses the organic mass balance between the inlet and outflow fluid, and the second member is substrate consumption of microorganisms.

UN s + S e (2)

Here Q is the flow rate of the inlet fluid (m 3 days -1 ), and Y is the yield coefficient (kg MLSS kg COD -1 ), V is the reactor volume (m 3 ) and S ± is the inlet fluid in the COD (mgl -1 ). All parameters used in these calculations are summarized in Tables 1 and 2.

Table 1

Values of kinetic and stoichiometric parameters used in the calculations

Parameter Unit Value kd 1 day -1 0,028 And R 2 '3 mgl -1 100 Y 3 kg MLSS kg COD -1 0.5 β 3 kg COD kg MLSS -1 1.2 μ ™ 2.3 day -1 3 2. table In the calculations used operating parameters values 3 * Parameter Unit Value Q m 3 days _1 1 · 10 3 S e (t = 0) mgl -1 30 Ski mgl -1 400 x (t = 0) mgl -1 5000

* Grady et al. (1999) 1 Nagaoka et al., Yamanishi S. and Miya A. (1998) Modelingof biofouling byextracellular polymers in membrane separation activation System, WatrScience and Technology 38 (4-5) 497-504.

2 Henze Μ. , Grady CPL, Gujer W., Marais GVR and Matsuo T. (1987) The General Model Forum, single-sludge wastewátr treatment systems, Wátr Research 21 (5) 505-515.

3 Grady CPL, Daigger GT and Lim HC, (1999) Biological Wastewater Treatment, pp. 61-125, Marcel Dekker, NY.

• · ·· * «· · · * · · · · ··

DETAILED DESCRIPTION OF THE INVENTION

Meaning of terms

In the present specification, the following abbreviations and terms are used:

AcAm means acrylamide; DMAEA «BCQ is dimethylaminoethylacrylate benzyl chloride quaternary salt; DMAEA «MCQ is a diethylaminoethylacrylate methyl chloride quaternary salt; EpiDMA is epichlorohydrin dimethylamine; DADMAC means diallyl dimethylammonium chloride; pDADMAC is poly (diallyldimethylammonium chloride); and PEI in polyethyleneimine.

The term "amphoteric polymer" means a polymer derived from cationic monomers and anionic monomers and optionally other nonionic monomers (monomers). Amphoteric polymers may have a net positive or negative charge. Typical amphoteric polymers include: acrylic acid / DMAEA-MCQ copolymer,

DADMAC / acrylic acid copolymer, DADMAC / acrylic acid / acrylamide terpolymer, etc.

The amphoteric polymer may be a derivative of zwitterionic monomers and cationic or anionic monomers and optionally nonionic monomers. Examples of typical amphoteric polymers containing tertiary ionic monomers include: DMAEA-MCQ / N, N-dimethyl-N-methacrylamide-propyl-N- (3-sulfopropyl) -ammonium betaine copolymer, acrylic acid / N, N-dimethyl-N-methacrylamopropopropyl-N- (3-sulfopropyl) ammonium betaine copolymer, DMAEA-MCQ / acrylic acid / N, N-dimethyl-N-methacrylamide-propyl-N- (3-sulfopropyl) -ammonium betaine terpolymer, etc.

• · • ·· * ► * * * · * ♦ · «♦ ··

As used herein, the term "anionic monomer" refers to a monomer having a negative charge over a certain pH range. Typical anionic monomers include, for example, acrylic acid and its salts, for example, but not limited to, sodium acrylate and ammonium acrylate, methacrylic acid and its salts, for example, but not limited to, sodium methacrylate and ammonium methacrylate, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and the sodium salt of AMPS, sodium vinyl sulfonate, styrene sulfonate, maleic acid and its salts, for example, but not limited to, sodium salt and ammonium salt, sulfonate, itaconate, sulfopropyl acrylate, or methacrylate or other water-soluble forms of these or other polymerizable carboxylic acids or sulfonic acids. Sulphomethylated acrylamide, allyl sulfonate, sodium vinyl sulfonate, itaconic acid, acrylamide methylbutanoic acid, fumaric acid, vinyl phosphonic acid, vinylsulfonic acid, allyl phosphonic acid, sulfomethylated acrylamide, phosphonomethylated acrylamide, and the like.

The term "cationic polymer" refers to a polymer having a positive charge. The cationic polymers of the present invention include polymers containing only cationic monomers and polymers containing cationic and nonionic monomers. Cationic polymers include condensation polymers of epichlorohydrin and a diaiki-1-monoamine or polyamine and condensation polymers of ethylene dichloride and ammonia or formaldehyde and an amine salt. The cationic polymers of the present invention include solution polymers, emulsion polymers, dispersion polymers, and structurally modified poly13.

as disclosed in PCT US01 / 10867.

The term "cationic monomer" refers to a monomer having a net positive charge. Typical cationic monomers include, for example, dialkylaminoalkyl acrylates and methacrylates and their quaternary or acidic salts, for example, but not limited to, dimethylaminoethyl acrylate methyl chloride quaternary salt, dimethylaminoethyl acrylate methyl sulfate quaternary salt, dimethylaminoethyl acrylate benzyl chloride quaternary salt, dimethylaminoethyl acrylate sulfuric acid salt, dimethylaminoethyl acrylate hydrochloride salt, dimethylaminoethyl methacrylate methyl chloride quaternary salt, dimethylaminoethyl methacrylate methyl sulfate quaternary salt, dimethylaminoethyl methacrylate benzyl chloride quaternary salt, dimethylaminoethyl methacrylate sulfuric acid salt, dimethylaminoethyl methacrylate hydrochloric acid salt, diaicylaminoalkyl acrylamides or methacrylamides and their quaternary or acidic salts, e.g. dimethylaminopropylmethacrylamide methylsulfate quaternary salt, dimethylaminopropyl methacrylamide sulfuric acid salt, dimethylaminopropyl methacrylamide hydrochloric acid salt, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, diallyl diethylammonium chloride and diallyldimethylammonium chloride. Alkyl groups are generally C1-C4 alkyl.

"Conditioning" means precipitating a soluble biopolymer and coagulating and flocculating the particulate and colloidal organic matter present in the liquid mixture (to produce larger particle aggregates that increase the flux on the membrane of the membrane bioreactor and reduce membrane sealing).

The term "hydraulic residence time (HRT)" refers to the length of time the wastewater is in the bioreactor. It is obtained that the total volume of the bioreactor is divided by the flow rate of the inlet material.

"Liquid mixture or" sludge "refers to wastewater, microorganisms used for the decomposition of organic matter in wastewater, material containing organic matter from cellular species, admixture of cellular by-products and / or waste products or cell-containing debris. The liquid mixture may include colloidal and particulate matter (e.g., biomass / bio solids) and / or soluble molecules or biopolymers (e.g., polysaccharides, proteins, etc.).

The term "mixed liquor suspended solids (MLSS)" means the concentration of biomass that treats organic matter in the liquid mixture.

The term "monomer" refers to a polymerizable allyl, vinyl or acrylic compound. The monomer may be anionic, cationic or non-ionic. Vinyl monomers are preferred, and acrylic monomers are preferred.

The term "nonionic monomer" means a monomer that is electrically neutral. Typical nonionic monomers include, for example, acrylamide, methacrylamide, N-methylacrylamide, N, N'-dimethyl (meth) acrylamide, Ν, Ν-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-tert-butyl ) acrylamide, N- (2-hydroxypropyl) methacrylamide, N-methylolacrylamide, N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, poly (ethylene glycol) (meth) acrylate, poly (ethylene glycol) ) monomethyl ether mono (meth) acrylate, Ninyl-2-pyrrolidone, glycerol mono ((meth) acrylate), 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, vinylmethylsulfon, vinyl acetate , glycidyl (meth) acrylate, etc.

The term "prevention" means prevention and inhibition.

The term "sludge residence time (SRT)" refers to the length of time during which the microorganisms that approximate the sludge remain within the bioreactor. The SRT is calculated by dividing the total amount of sludge in the bioreactor by the sludge removal rate.

The term " zwitterionic monomer " means a polymerizable molecule containing cationic and anionic (charged) functional groups in the same ratio so that the whole molecule is neutral. Typical zwitterionic monomers include, for example, N, N-dimethyl-N-acryloyl-oxyethyl-N- (3-sulfopropyl) -ammonium betaine, N, N-dimethyl-N-acrylamidopropyl-N- (2-carboxymethyl) -ammonium betaine , N, N-dimethyl-N-acrylamidopropyl-N- (3-sulfopropyl) ammonium betaine, N, N-dimethyl-N-methacrylamide-propyl-N- (3-sulfopropyl) -ammonium betaine (DMMAPSB), N, N-dimethyl-N-acrylamide-propylN- (2-carboxymethyl) -ammonium betaine, 2- (methylthio) ethyl methacryloyl-S- (sulfopropyl) sulfonium beta, 2 - [(2-acryloylethyl) dimethylammonium] ethyl-2 methylphosphate, 2- (acryloyl oxyethyl) -2 '(trimethylammonium) ethyl phosphate, [(2-acryloxyethyl) dimethylammonium] methylphosphonic acid, 2-methacryloxyethylphosphorylcholine (MPC), 2 - [(3) -acrylamopropyl) dimethylammonio] ethyl 2'-isopropylphosphate (AAPI), 1-vinyl-3- (3-sulfopropyl) imidazolium hydroxide, (2acryloxyethyl) carboxymethylmethylsulfonium chloride, 1- (3-sulfopropyl) -2-vinylpyridinium betaine, N- (4-sulfobutyl) -N-methylΝ, Ν-diallylamine ammonium betaine (MDABS), N, N-dia 11-N-methyl-N- (2-sulfoethyl) ammonium betaine and the like. A preferred zwitterionic monomer is N, N-dimethyl-N-methacrylamide propyl-N- (3-sulfopropyl) ammonium betaine.

The term "zwitterionic polymer" refers to a polymer containing a zwitterionic monomer and optionally other nonionic monomers (monomers). Typical zwitterionic polymers include homopolymers such as the homopolymer of N, N-dimethyl-N- (2-acryloyloxyethyl) -N- (3-sulfopropyl) ammonium betaine, copolymers such as acrylamide and N, N-dimethyl. The copolymer of N- (2-acryloxyethyl) -N- (3-sulfopropyl) ammonium betaine and terpolymers such as acrylamide, N-vinyl-2-pyrrolidone and 1- (3-sulfopropyl) -2-vinylpyridinium. betaine terpolymer. In the zwitterionic polymers, all polymer chains and chain segments are strictly electrically neutral. Therefore, zwitterionic polymers represent a subset of amphoteric polymers that necessarily maintain charge neutrality on all polymer chains and segments because of the anionic charge and cationic charge on the same zwitterionic monomer.

"Reduced Specific Viscosity (RSV) is the amount typical of the polymer chain length and the average molecular weight. RSV is measured at a given polymer concentration and temperature range and • 4 **. Oljuk · * «- Λ Λ * - Λ“ ““ “oljuk oljuk oljuk oljuk oljuk oljuk oljuk oljuk oljuk oljuk oljuk oljuk oljuk oljuk oljuk oljuk oljuk oljuk»

2L -1 IZM

c where η is the viscosity of the polymer solution;

T0 is the viscosity of the solvent at the same temperature, and c is the concentration of the polymer in the solution.

As used herein, the concentration of ac is in grams per 100 ml or g / deciliter. Therefore, the unit of RSV is dl / g. RSV was measured at 30 ° C. The viscosity of η and ηο was measured with a 75-inch Cannon-Ubbelhode semi-micro dilution viscometer. The viscometer is held vertically in a constant temperature bath set at 30 ± 0.02 ° C. The error inherent in the calculation of RSV is approx. 2 dl / g. When measuring similar RSV values for two linear polymers of the same or very similar composition, it is suggested that the polymers have similar molecular weights, provided that the polymer samples are treated identically and that the RSVs are measured under the same conditions.

IV is an intrinsic viscosity, which is the limit of RSV for infinite polymer dilution (i.e., when the polymer concentration is zero). The IV-1 in the meaning of the present disclosure is derived from the axial section of the graph of RSV plotted against the polymer concentration in the range of 0.015-0.045% by weight polymer.

Preferred embodiments

The water-soluble, cationic, amphoteric or zwitterionic polymers of the present invention are added to the MBR to facilitate the incorporation of colloidal particles, such as cell fragments and bacteria into aggregate or flock structures, and / or increase the porosity of the cake. The water soluble polymers may be solution polymers, latex polymers, dry polymers or dispersion polymers.

The term "latex polymer" refers to an invertable water-in-oil polymer emulsion comprising a cationic, amphoteric or zwitterionic polymer of the present invention in the aqueous phase, a hydrocarbon oil in the oily phase, an emulsifying agent in water-in-oil, and optionally an inverting surfactant. The inverse emulsion polymers form a continuous hydrocarbon phase with water-soluble polymers distributed as micron-sized particles in the hydrocarbon matrix. The latex polymers are "inverted or activated for use by shear, dilution, and generally another surfactant, which may also be a component of the inverse emulsion, by release of the polymer in the particles."

Water-in-oil emulsion polymers are described, for example, in 2,982,749; 3,284,393; and U.S. Patent No. 3,734,873. See also Hunkeler et al., "Mechanism, Kinetics and Modeling of the InverseMicrosuspension Homopolymerization of Acrilamide, Polymer (1989), 30 (1), 127-42; and Hunkeler et al., Mechanism, Kinetics and Modeling of Inverse-Microsuspension Polymerization: 2. Copolymerization of Acrilamide with Quaternary Ammonium Cationic Monomers, Polymer (1991), 32 (14), 2626-40. the works

The latex polymers are prepared by dissolving the desired monomers in the aqueous phase, dissolving the emulsifier (s) in the oily phase, emulsifying the aqueous phase in the oily phase to produce the water-in-oil emulsion, in some cases homogenizing the water in the oil emulsion, polymerize the monomers dissolved in the aqueous phase of the water-in-oil emulsion to produce the polymer in water-in-oil emulsion. If desired, a self-inverting surfactant can be added to the material after polymerization to produce a self-inverting emulsion in water-in-oil.

The term "dispersion polymer" refers to a water-soluble polymer dispersed in a continuous aqueous phase containing one or more inorganic / organic salts. Typical examples of polymers produced by dispersing water-soluble monomers in a continuous aqueous phase include, but are not limited to, 4,929,655; 5

006,590; U.S. Patent Nos. 5,597,859 and 5,597,858 and European Patent Specifications 657,478 and 630,909, and PCT / US01 / 09060.

The general procedure for producing dispersion polymers is as follows. The types and amounts of the individual components (e.g., salts and stabilizing polymers) in the formulation will vary depending on the particular polymer to be synthesized.

An aqueous solution comprising one or more inorganic salts, one or more monomers and optionally additional water-soluble monomers, optionally polymerization additives such as chelating agents, pH buffers, chain transfer agents, branching or space-melting agents, and one or more water-soluble agents. comprising a stabilizer polymer, loaded into a reactor equipped with stirrers, a thermocouple, a nitrogen bubbling tube, and a water condenser.

The monomer solution is vigorously stirred, heated to the desired temperature, and a water-soluble initiator is added. The solution was bubbled with nitrogen while maintaining the temperature and stirring for hours. After this time, the products are cooled to room temperature and, optionally, the post-polymerization additives are charged to the reactor. The dispersions of the water-soluble polymers forming a continuous aqueous phase are free-flowing liquids, which generally have a viscosity of 0.1 to 10 Pa, measured at low shear.

The term "solution polymer" refers to a water-soluble polymer in a solution in a continuous aqueous phase.

One or more monomers are added to the reaction vessel during the solution polymerization process and neutralized with a suitable base. Water is then added to the reaction vessel which is heated and bubbled. Polymerization catalysts may also be added to the reaction vessel at the beginning of the process or may be added gradually during the reaction. Water-soluble polymerization initiators, such as any azo or redox initiator, or a combination thereof, are added to the reaction mixture in a separate stream at the same time, together with the monomer solution. Heating or cooling can be used to control the reaction rate as needed. An additional initiator may be used after the addition is complete to reduce the amount of residual monomer.

The term "dry polymer" refers to a polymer produced by gel polymerization. In the gel polymerization process, an aqueous solution of water-soluble monomers, usually 20-60% by weight, optionally with a polymerization or process additive, such as chain transfer agents, chelating agents, pH buffers or surfactants, is placed in a reaction tube equipped with a nitrogen bubbling tube. Polymerization initiator was added, the solution was bubbled with nitrogen and the reaction temperature allowed to rise without regulation. Once the polymerized material has cooled, the resulting gel is removed from the reactor, crushed, dried and ground to a suitable particle size.

In a preferred embodiment, the water-soluble cationic, amphoteric, or zwitterionic polymers have a molecular weight of from about one to about one. 2000-10,000

000 daltons.

In another preferred embodiment, the cationic polymer is a copolymer of acrylamide and one or more cationic monomers, which may be a dialyldimethylammonium chloride, a dimethylaminoethyl acrylate methyl chloride quaternary salt, a dimethylaminoethyl methacrylate methyl chloride quaternary salt, and a dimethylaminoethyl acrylate benzyl chloride quaternary salt.

In another preferred embodiment, the cationic polymer is at least about 30%. 5 mol% of cationic charge.

In another preferred embodiment, the cationic polymer is a copolymer of dimethyldimethylammonium chloride / acrylamide.

In another preferred embodiment, the amphoteric polymer may be dimethylaminoethyl acrylate methyl chloride quaternary salt / acrylic acid copolymer, diallyl dimethylammonium chloride / acrylic acid copolymer, dimethylaminoethyl acrylate methyl chloride salt / N, N-dimethyl-N-methacrylamide propyl-N- ( 3-sulfopropylammonium betaine copolymer, acrylic acid / N, N-dimethyl-N-methacrylamino-propyl-N- (3-sulfopropyl) -ammonium betaine copolymer and DMAEA-MCQ / acrylic acid / NN-dimethyl-N-methacrylamide propyl-N - (3-sulfopropyl) ammonium betaine terpolymer.

In another preferred embodiment, the amphoteric polymer has a molecular weight of from about one to two. 5000-2,000,000 Daltons.

In another preferred embodiment, the ratio of cationic charge equivalents to anionic fillings in the amphoteric polymer is equal to approx. 0.2: 9.8 to 9.8: 0.2.

Another advantageous embodiments cationic polymer cations well charging 100 mol%. Another advantageous embodiments cationic polymer molecular its weight is approx. 2000-500 000 daltons. Another advantageous embodiments cationic polymer may

polydiallydimethylammonium chloride, polyethyleneimine, polyepiamine, cross-linked with polyepiamine with ammonia or ethylenediamine, condensation polymer of ethylene chloride and ammonia, condensation polymer of triethanolamine and tall oil fatty acid, poly (dimethylaminoethylmethacrylate sulfuric acid salt) and poly (dimethylaminoethylacrylate methyl chloride quaternary salt).

In another preferred embodiment, the water-soluble zwitterionic polymer is present in an amount of about one to two. 1-99 mol% of N, N-dimethyl-N-methacrylamino-propyl-N- (3-sulfopropyl) ammonium betaine and ca. 99-1 mol% of one or more nonionic monomers.

In another preferred embodiment, the nonionic monomer is acrylamide.

The MBR unit combines two basic processes into a single process: biodegradation and membrane separation, where the suspended solids and biodegradable microorganisms are separated from the treated water by a membrane filter unit. See Water Treatment Membrane Processes, McGraw-Hill,

1996, p. 17.2. The entire biomass remains in the system, so we can control the residence time of the microorganisms in the reactor (sludge aging) and the disinfection of the effluent from the process.

In a typical MBR unit, the effluent 7 is discharged into the aeration tank 1 by gravity or pumping, where it is brought into contact with the biomass which biodegrades the organic matter in the waste water. The aeration device 5, such as a gas blower, provides oxygen to the biomass. The resulting liquid mixture is pumped from the aeration tank into the membrane module 2, where it is filtered under pressure on a membrane or drawn through a membrane under vacuum. The effluent 11 is removed from the system while the concentrated liquid mixture is returned to the bioreactor. The excess sludge 9 is pumped out to maintain constant sludge aging and the membrane is regularly cleaned by rinsing, chemical washing, or both.

The membranes used in the MBR can be ultra-, micro- and nanofiltrates, internal or external coated, hollow fiber, tubular, flat, organic, metal, ceramic membranes, and the like. Preferred membranes in bulk applications are, for example, hollow fibers having an outer ultrafiltration coating, a flat plate (stacked) microfilter and hollow fibers having an outer microfiltration coating.

Preferred materials include chlorinated polyethylene (PVC), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polysulphone (PSF), polyethersulfone (PES), polyvinyl alcohol (PVA), cellulose acetate (CA), regenerated cellulose (RC), and the like. inorganic materials.

Optionally, 6 sludge breakers can be connected to the MBR to enhance the demolition of the sludge. From the aeration tank 1, the excess sludge 9 is pumped into the demolition unit for further demolition. The liquefied sludge 8, which leaves the decomposer, is returned to the bioreactor and fed. Sludge decomposition can be done, for example, by ozone, alkaline treatment, heat treatment, ultrasound, etc. In this case, the protoplasmic material in the broken sludge contributes to the increased level of biopolymers (i.e., proteins, polysaccharides) in the liquid mixture. Excess biopolymers are removed by polymer treatment as described herein.

Waste water can be pretreated before being introduced into the MBR. For example, a sedimentation grid, a sand catcher, a rotating drum screen may be used to remove coarse solids.

In industrial plants where synthetic oils are present in the untreated wastewater, such as oil refineries, pre-treatment for oil removal is carried out in units such as the sloping separator and the induced air flotation unit (IAF). Often, a cationic flocculating agent, such as a copolymer of DMAEM and AcAm, is used in the IAF unit to aid in the removal of oil. The excess phosphate is sometimes precipitated from the bioreactor by adding metal salts such as ferric chloride, so that the phosphate does not pass through the membrane and does not get into the effluent.

Depending on the final use of the water and the purity of the MBR permeate, the treated wastewater may be subjected to post-treatment. For example, a water-barrage regiment, where the treated wastewater is finally returned to a water reservoir used as a drinking water source, can purify the permeate by reverse osmosis (RO) to reduce the dissolved mineral content. When water is returned to a process, the process requirements may require further treatment of the permeate to remove stubborn organic matter that is not removed by the MBR. In these cases, for example, a nanofiltration or carbon adsorption process can be used. Finally, any biologically treated wastewater can be further disinfected before being introduced into the receiving stream, usually by the addition of sodium hypochlorite, but this is not necessary when discharged into urban wastewater.

As discussed above, the total retention of biomass in the MBR process by the membrane process allows for large MLSS to be maintained in the bioreactor, and this large MLSS allows a longer solid residence time (SRT). Thus, the MBR sludge rate, which is inversely proportional to the SRT, is lower than in the conventional sludge process. 0.3 kg sludge / kg COD. However, the cost of sludge treatment in the MBR plant is still estimated at 3040% of the total cost.

As discussed above, sludge formation can be significantly reduced by simply increasing the hydraulic residence time (HRT) of the bioreactor or the target suspended solids (MLSS). However, this method accelerates membrane sealing and ultimately increases the "membrane cleaning frequency."

Large HRT and large MLSS can cause large SRT. Under these conditions, the microorganisms remain in the bioreactor and during this time some of the old microorganisms are automatically decomposed. Decomposition of substantial amounts of mixed protoplasmic material, such as polysaccharides, proteins, etc., during decomposition. produced. These substances are collectively referred to as "biopolymers." This biopolymer is added to the background biopolymer, the so-called microorganism selected by the microorganisms. extracellular polymer (ECP). Consequently, the large SRT leads to a high biopolymer level, which plays a major role in membrane clogging.

Thus, sludge reduction induced by increasing HRT and / or MLSS is limited by accelerated clogging of the membrane caused by the biopolymer. The high level of soluble biopolymer present in the liquid mixture can be reduced with the polymers of the present invention reacting with the biopolymers, and the biopolymers are coagulated and flocculated to compress them into larger particles to form insoluble precipitate.

In practice, the formation of mud in a new MBR facility

It can be reduced by 50-90% since the use of the polymers described in this specification allows the HRT to be reduced to approx. Increase to 10-15 hours without increasing MLSS.

In an existing facility where the value of HRT is given, the sludge formation is approx. It can be reduced by 30-50%, since the use of the polymers described in the present disclosure allows the MLSS to approx. 2-2.5% increase.

The cationic, amphoteric or zwitterionic polymers may be introduced into the aeration tank / bioreactor by various methods, for example, by adding it to the feed waste water before the bioreactor or directly into the bioreactor.

The polymer must always be carefully mixed with the liquid mixture in the bioreactor to achieve maximum adsorption. This can be achieved by introducing the polymer into an area of the bioreactor with an aeration nozzle. The bioreactor is so called. "Dead zones with little or no flow are to be avoided. In some cases, a submerged propeller mixer may be required to increase the mixing in the pool, or the sludge may be recycled through a side loop.

The solution polymers can be administered with a chemical measuring pump, such as LMI Model 121 (manufactured by Milton Roy, Acton, MA).

The recommended polymer dose, based on the mixture of liquids in the bioreactor, is approx. 1-2000 ppm based on the active ingredient for about 12% MLSS (suspended solids in a liquid mixture). If the MLSS value is less than 1%, we can use proportionally less po28 limits. The polymer may be periodically pumped into the liquid mixture in the bioreactor or into the feed water stream. The polymer can be pumped continuously or continuously into the wastewater. When the polymer is continuously pumped into the feed waste water, the dose is substantially less, about.

0.25-10 ppm.

Overdose of the polymer may reduce biological activity and removal of organic matter from the bioreactor. Therefore, a small polymer dose should be used initially, e.g. 25-100 ppm in the liquid mixture. Further polymer can then be added to increase the flux while maintaining biological activity. The value of the permeate TOC (total organic carbon), COD (chemical oxygen demand) or BŐD (biological oxygen demand) can be checked to ensure biological activity.

Similarly, a small vessel may be tested with samples from the liquid mixture. Using a four-blade mixer, an increasing amount of polymer was added to the sample vials and a vessel left untreated. After mixing, the samples are allowed to settle for several hours to allow the solid to collect at the bottom of the vessel. The turbidity of the water (supernatant) above the settled solid is measured to verify the effectiveness of the polymer dose. The Hach Comapny (Loveland, Co) turbidimeter can be used. The dose that gives less turbidity than the untreated sample usually increases the flux in the MBR.

If the polymer is overdose, the polymer addition should be suspended until the biological activity returns to the normal level. It may also be necessary to remove several sludge from the bioreactor to facilitate the return of bioactivity. Addition of biologically enhancing products containing the appropriate bacteria may also be useful to restore activity after polymer overdose.

The above examples are better understood by reference to the following examples, which are for the purpose of illustration only, but are not intended to limit the scope of the invention.

The typical cationic, amphoteric or zwitterionic polymers of the present invention are shown in Table 3. Polymers B and C are manufactured by Ciba (Tarrytown, NY), M and N are BASF (Mount Olive, NJ). All other polymers are manufactured by Ondeo Nalco

Company, Naperville, IL.

Table 3

Typical polymers

Polymer Chemical composition molecular Weight IV (RSV) % active substance THE Epi-DMA, ammonia, crosslinked 0.18 · 10 3 50 B Epi-DMA, EDA, cross-linked 0.3-10 -3 50 C Epi-DMA, EDA, cross-linked 45 D Epi-DMA, linear 0.1-10 -3 50 E pDADMAC 0.2-10 -3 30 F pDADMAC 1.0-10 -3 18

- 3.

G Ethylene dichloride / ammonia polymer <15,000 30 Η Poly (dimethylaminoethyl methacrylate salt) 100,000 30-40 I Poly (triethanolamine methyl chloride quaternary salt) 50,000 100 J Poly (bis-hexamethylenetriamine), crosslinked with EO by diethylglycolone, reacting with diepichlorohydrin, further crosslinked with EP-HCl salt <500,000 50 K N, N-Diallycyclohexylamine / Nylylcyclohexylamine Mixture and Acrylamide Copolymer <500,000 80 L Triethanolamine and tall oil fatty acid, copolymer of quaternary salt of methyl chloride <100,000 50 Μ polyethyleneimine 0.32-10 '3 20 N Polyethyleneimine, crosslinked with EO 0.35 · 10 3 20 0 DADMAC / Acrylamide Copolymer 1.2-10 -3 20 Ρ Dimethylaminoethylacrylate methyl chloride quaternary salt / acrylamide copolymer 16-24 • 10 3 30 Q Dimethylaminoethylacrylate methyl chloride quaternary salt / acrylic acid 25

(70:30 mol: mole) copolymer R DADMAC / acrylic acid (90:10 mo 1: 1) copolymer 1.2-10 -3 20 S DADMAC / acrylic acid (51:49 mo 1: mo 1) copolymer (0.9) • 10 -3 35 T Acrylamide / N, N-dimethyl-N-methacrylamide-propyl-N- (3-sulfopropyl) ammonium betaine (99: 1 mol: mol) copolymer (20-25) • 10 -3 U Acrylamide / N, N-dimethyl-N-methacrylamino-propyl-N- (3-sulfopropyl) -ammonium betaine / dimethylaminoethylacrylate methyl chloride quaternary salt (99.5: 1: 0.5 mol: mol: mol) terpolymer (20-25) • 10 -3

Example 1

A sample of an aerobically digested liquid mixture from a US-Western city wastewater treatment plant (about 10-1.5% TSS) was mixed with a typical water-soluble polymer of the present invention using a blade mixer at 110 rpm. , 5 minutes. The mixture was placed in an Amicon Model 8400 stirred cell (Millipore Corporation, Bedford, MA), and was carried through Durapore® polyvinylidenedifluoride membrane with a pore size lis nominá32 · * 0.1 micron and effective memebránterülete was 0.0039 m 2 (Millipore Corporation, Bedford, MA) at a constant pressure of 179 kPa. Flux was determined by measuring the permeate on a Mettler Toledo Model PG5002S scale at certain intervals, from which the top loading can be loaded. The mass was recorded with a computer at 2 or 6 second intervals. The volume was calculated by assuming a density of 1.00 mg / l, and the density was not corrected by the temperature. Flux was calculated as:

J = 913.7 AW / At, where J is flux (1 / m 2 / h);

AW is the difference between 2 mass measurements (in grams); and A is the difference between 2 timings (in seconds).

The results are shown in Table 4.

Table 4

Membrane Flux Typical for Cationic Polymers in Liquid Mixture

At a pressure of 179 kPa

Polymer Active dose, ppm Fluxus, LMH, 80 g no 0 65 THE 50 576 THE 100 1296 THE 150 2088

• ·· · · ···

D 100 295 E 150 900 E 90 612 E 30 252 F 150 1836

Further tests were performed on the liquid mixture from the same urban plant. In these studies, liquid mixtures were mixed with or without polymer at 275 rpm for 15 minutes before being tested for Amicon. The sample was introduced into the cell at a pressure of 103 kPa. The results are shown in Table 5.

Table 5

Membrane Flux Typical for Cationic Polymers in Liquid Mixture

At 103 kPa pressure

Polymer Active dose, ppm Fluxus, LMH, 80 g (70 g) no 0 57.6 THE 100 410.4 I 100 358.9 H 100 359.3 L 100 181.4 K 100 57.24

• ·· · · ···

G 100 284.4 N 100 286.9 M 100 1728 M 80 860.4 M 40 482.4 M 20 162 no 0 (49) THE 100 (522) P 100 (183)

The data in Tables 4 and 5 show that the use of water-soluble cationic polymers for sludge treatment significantly increases the flux through the membrane. Particularly, the NH 3 cross-linked Epi-DMA exhibits significant 700% flux growth and PEI ca. 1500% growth. Other cationic polymers (such as linear epi-DMA and pDADMAC) also have higher flux than when not treating sludge.

Example 2.

The excess soluble cationic polymer was measured by adding amounts of a variable cationic polymer (Epi-DMA) to a liquid mixture from one of the central-western urban wastewater treatment plants in the United States, mixed at 110 rpm. Centrifuged at 000 rpm for 25 minutes, then the residual polymer in the supernatant (centrate) by colloidal titration with a solution of polyvinylenic acid potassium salt (PVSK) of 0.001 M. The results are summarized in Table 6 below.

Table 6

The remaining polymer is in the supernatant, ppm

Active polymer in sludge

22.5

135

1350

1800

2250

4500

Active polymer in the supernatant

4.5

79.7

211

1650

As shown in Table 6, no polymer was detected in the centrifuged aqueous supernatant at polymer doses that significantly increased membrane flux. Doses greater than 30 times higher than optimal are required to cause excess polymer to appear in the supernatant. This is a very important discovery because, to our knowledge, excess polymer breaks the membrane surfaces, which greatly reduces membrane flux.

Example 3

Samples of about 20 liters in the United States' · · · ·

States from a Western MBR that handles urban wastewater, were saturated with air overnight and tested the next day. Ά the sample was cooled overnight in a fridger and then warmed to room temperature for the next few days. A cationic polymer (2.0 g of a 1% polymer solution) and 198 g of a liquid mixture were added to a 400 ml beaker. The mixture was agitated with motor agitators for 15 minutes at 275 rpm to redisperse the solid. The mixed slurry was transferred to the Amicon cell immediately prior to the screening test, with a membrane of polyvinylidene fluoride having a nominal pore size of 0.2 microns.

The mixture was passed through a membrane at either 103 kPa or 55 kPa. Flux was determined by measuring the permeate at a certain time interval in a Mettler Toledo Model

PG5002S "top-loading scale. The mass was recorded with a computer at 2-second intervals. The volume was calculated by assuming a density of 1.00 mg / l, and the density was not corrected by the temperature. Flux was calculated as in Example 1.

After examining the sludge sample, the membrane was discarded. Each polymer treatment study also included a study in which no polymer was added to determine the basis of comparison. This assay compares the fluxes of the polymer-treated sludge with the flux of the untreated liquid mixture. Dose, chemical composition, pressure, etc. were measured for this purpose. effect on the flux. The results are shown in Table 7.

• · ·

Table 7

Membrane Flux is typical for cationic polymers in MBR liquid mixture

103 and 55 kPa pressure

Polymer Pressure, Active Substance Fluxus 80 g kPa zis, ppm tena, LMH * no 103 0 311.4 THE 103 25 806.4 THE 103 50 1155.6 THE 103 100 1512 M 103 0 370.8 M 103 20 928.8 M 103 40 1915.2 no 55 0 138.2 THE 55 25 367.2 THE 55 50 500.4 THE 55 100 694.8

* The flux of pure water at 55 kPa is 1440 LMH at 103 kPa

2160 LMH was.

The data in Table 7 show that flux significantly increases on the membrane at both 55 kPa and 103 kPa when polymers A and M are used to condition the sludge prior to testing.

Example 4.

One of the U.S. units of the Mid-West MBR38 of the United States of America, which treats urban wastewater, has taken a liquid mixture and mixed with different doses of Q amphoteric polymer, then filtered on a dead-end filter cell on a Kubota-branded flat sheet membrane 103 at a pressure of kPa while the treated liquid mixture was stirred at 300 rpm at ° C. The comparative liquid mixture, which was not treated with polymer, was also filtered under similar conditions. The percent increase in permeate flux after amphoteric polymer treatment is shown in Table 8 at various doses.

Table 8

Membrane Flux Growth in Typical Amphoteric Polymer MBR Liquid Mixture from a Midwestern MBR Unit of the United States of America

Polymer Dose (Active Substance, ppm) % flux increase 75 23 250 32 875 55 2000 117

The data in Table 8 show that flux significantly increases on the membrane relative to the reference sample when a typical amphoteric polymer is used to pre-test the fluid mixture.

Part 5

One of the western MBR units in the United States that handles urban wastewater was mixed with a liquid mixture and mixed with the Q amphoteric polymer, and the membrane flux was measured as in Example 4. The results are shown in Table 9.

Table 9

Membrane Flux Growth in Typical Amphoteric Polymer MBR Liquid Mixture from one of the Western MBR Units in the U.S.

Polymer Dose (Active Substance, ppm) % flux increase 25 4 75 485 250 818

The data in Table 9 show that flux significantly increases on the membrane relative to the reference sample when a typical amphoteric polymer is used to pre-test the fluid mixture.

Example 6

One of the western MBR units in the United States of America that handles urban wastewater was mixed with a liquid mixture and mixed with amphoteric R, and the membrane flux was measured as in Example 4. The results are shown in Table 10.

· · · · · · · «· * ·

Table 10

Membrane Flux Growth in Typical Amphoteric Polymer Liquid Mixture from a United States Western MBR Unit

Polymer Dose (Active Substance, ppm) % flux increase 105 28 350 34

The data in Table 10 show that flux significantly increases on the membrane relative to the comparative sample when a characteristic amphoteric polymer is used to pre-test the fluid mixture.

Example 7

In order to confirm the complexing of the polysaccharide in the liquid mixture with the amphoteric polymer, the polysaccharide level was tested colorimetrically in the supernatant of the liquid mixture after the polymer was added to the liquid mixture and centrifugation was performed.

Table 11 shows the amount of residual glucose (direct degree of polysaccharide) in the liquid mixture after complexation with Q amphoteric polymer, in the case of a liquid mixture derived from one of the western MBR units of the United States of America treating urban wastewater.

* Λ 4 · «·» · · · ·

Table 11

Effect of a typical amphoteric polymer on the polysaccharide level in a liquid mixture from one of the western MBR units in the United States of America

Polymer Dose (Active Substance, ppm) Glucose (ppm) 0 (comparative) 7.96 25 4.14 75 3.50 250 3.80

As shown in Table 11, when a typical polymer of the present invention is used to condition the liquid mixture, the polysaccharide level in the MBR fluid mixture is significantly reduced, which significantly increases flux as shown in Table 9.

In addition, no residual polymer was detected in the supernatant of a liquid mixture from one of the mid-western MBR units of the United States of America, after addition of an amphoteric polymer containing 2000 ppm of active substance, and centrifuging the liquid mixture thus treated. This indicates that the polymer added to coagulate the suspended solids and to complex the soluble biopolymer has been almost completely utilized. Therefore, it is unlikely that the added amphoteric polymer will itself contribute to the membrane clogging while leading to greater permeate flux.

Furthermore, the quality of the permeate is not impaired by the polymer treatment, as evidenced by the turbidity of the permeate, which is generally below 0.5 NTU after the polymer treatment, in a slurry liquid mixture from the western and central western MBR of the United States of America. both.

EXAMPLE 8 Liquid mixture from a western plant in the United States of America was treated with a typical amphoteric polymer according to the method described in Example 4, except that a flow cell was used with immersed membranes. The degree of flux growth is indicated by the suction pressure required for a permanent permeate flux. Thus, the greater the suction pressure required for a given permanent permeate flux, the greater the membrane clogging. The suction pressure profile was measured for 24 hours in the case of the comparative sample and the polymer-treated liquid mixture with 3 0 LMH constant permeate flux. The sludge volume was 81, and the air flow rate for the membrane was 10 1 / min. The results are shown in Table 12.

• 4 - '>*''' · · «4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 · * 4 »-« »

Table 12

Effect of treatment with a typical amphoteric polymer on suction pressure when passing through a membrane of a liquid mixture from one of the western MBR units in the United States of America

Time (hours) Suction Pressure (kPa) Comparative Polymers containing 13 ppm of active ingredient 0 0 0 3 3.0 1.5 6 8.1 2.1 9 12.0 3.2 12 15.7 4.5 15 19.2 5.9 18 22.1 7.4 21 25.9 9.2 24 27.9 11, 1

9. p live

Biopolymer removal efficiency with the cationic polymer was determined by IR as follows. The MBR liquid mixture was centrifuged and supernatant prepared. To the sample, cationic polymers P were added. The IR analysis of precipitate and supernatant showed that the majority of the biopolymer present in the supernatant was present in the precipitate and had only trace amounts of fluid. Also, nothing, 1.

.Ik44 showed that the cationic polymer causes membrane clogging when the concentration is less than 100 ppm in the liquid mixture.

A three-month trial trial showed that membrane clogging was delayed by polymer P. In a mixed cell batch experiment, no reduction in flux was observed even with 1000 ppm P polymer. In addition, bioactivity is also unaffected by cationic polymers such as polymer P and polymer A, even at extremely high polymer concentrations of 3000 ppm.

neither

Although the present invention has been described in detail for the sake of illustration, it is to be understood that the detailed description has served only this purpose and that many modifications and modifications may be made by the skilled artisan without departing from the scope and spirit of the invention if it remains within the range indicated by the claims. Any change covered by the equivalence of the meaning and the scope of the claims is within the scope of the invention.

···· ·· '

DISCLOSURE

COPIES

Claims (18)

  1. PATIENT INDIVIDUAL POINTS
    A method for conditioning a liquid mixture in a membrane biological reactor, characterized in that an effective coagulating and flocculating amount of one or more water-soluble cationic, amphoteric or zwitterionic polymers or combinations thereof are added to the liquid mixture.
  2. The process according to claim 1, wherein the water-soluble cationic, amphoteric or zwitterionic polymers have a molecular weight of from about 1 to about 2. 2000-10,000,000 Daltons.
  3. The process according to claim 1, wherein the cationic polymer is a copolymer of acrylamide and one or more cationic monomers, which may be a dialyldimethylammonium chloride, a dimethylaminoethyl acrylate methyl chloride quaternary salt, a dimethylaminoethyl methacrylate methyl chloride quaternary salt, and a dimethylaminoethyl acrylate. benzyl chloride quaternary salt.
  4. 4. The method of claim 3, wherein the cationic polymer is at least about 30%. 5 mol% of cationic charge.
  5. 5. The method of claim 3, wherein the cationic polymer is a dialyldimethylammonium chloride / acrylamide copolymer.
  6. 6. The method of claim 1, wherein the amphoteric polymer is dimethylaminoethyl acrylate methyl chloride quaternary salt / acrylic acid copolymer, diallyl dimethylammonium chloride / acrylic acid copolymer, dimethylaminoethyl acrylate methyl chloride salt / N, N-dimethyl-N -methacrylamide-propyl-N- (3-sulfopropyl) 46 ammonium betaine copolymer, acrylic acid / N, N-dimethyl-N-methacrylamide-propyl-N- (3-sulfopropyl) -ammonium betaine copolymer
    DMAEA-MCQ / acrylic acid / N, N-dimethyl-N-methacrylamide-propyl-N- (3-sulfopropyl) -ammonium betaine terpolymer.
  7. 7. A process according to claim 6, wherein the amphoteric polymer has a molecular weight of from about one to about one. 5000-2,000,000 Daltons.
  8. 8. A method according to claim 6, wherein the cationic charge equivalent and the anionic charge equivalents in the amphoteric polymer are about 30%. 0.2: 9.8 to 9.8: 0.2.
  9. 9. The method of claim 6, wherein the cationic charge of the cationic polymer is 100 mol%.
  10. 10. The method of claim 9, wherein the cationic polymer has a molecular weight of ca. 2000-500,000 Daltons.
  11. 11. A process according to claim 9, wherein the water-soluble cationic polymer is polydiallydimethylammonium chloride, polyethyleneimine, polyepiamine, cross-linked with polyepiamine ammonia or ethylenediamine, condensation polymer of ethylene chloride and ammonia, condensation polymer of triethanolamine and tall oil fatty acid, poly (dimethylaminoethylmethacrylate sulfuric acid) poly (dimethylaminoethylacrylate methyl chloride quaternary salt).
  12. 12. The method of claim 1, wherein the water-soluble zwitterionic polymer comprises from about one to about one. 1-99 mol% of N, N-dimethyl-N-methacrylamino-propyl-N- (3-sulfopropyl) -ammonium acetate and ca. 99-1 mol% of one or more nonionic monomers.
  13. 13. The method of claim 12, wherein the nonionic monomer is acrylamide.
  14. A method for treating waste water in a membrane biological reactor, wherein the microorganisms consume organic material in the waste water, thereby producing a liquid mixture comprising water, microorganisms, and soluble and suspended solids, characterized in that
    i) adding to the liquid mixture an effective coagulating and flocculating amount of one or more cationic, amphoteric or zwitterionic polymers, or mixtures thereof, to form a mixture comprising water, microorganisms and coagulated or flocculated solid; and ii) separating the purified water from the microorganisms and coagulated and flocculated solids by membrane filtration.
  15. 15. A method of preventing filter membrane clogging in a membrane biological reactor, wherein the microorganisms consume organic material in the waste water, in a liquid mixture containing water, microorganisms, and soluble, colloidal and suspended solids, and wherein the purified water from the liquid mixture is filtered through a filter membrane. separated by filtration, comprising adding one or more cationic, amphoteric or zwitterionic polymers to the liquid mixture in an amount sufficient to prevent membrane clogging.
  16. 16. A method for increasing flux on a filter membrane in a membrane biological reactor, wherein the microorganisms consume organic material in the waste water, in a liquid mixture containing water, microorganisms and soluble, colloidal and suspended solids, and wherein the purified water is selected from the liquid mixture by filtration through a filter membrane. characterized in that one or more cationic, amphoteric or zwitterionic polymers or combinations thereof are added to the liquid mixture in an amount effective to increase the flux.
  17. 17. A method for reducing sludge formation in a membrane biological reactor, wherein the microorganisms consume organic material in the wastewater, thereby producing a liquid mixture comprising water, microorganisms and dissolved, colloidal and suspended solids, and wherein the purified water is liquid. separating from the mixture by membrane filtration, characterized in that
    1) adding to the liquid mixture an effective coagulating and flocculating amount of one or more cationic, amphoteric or zwitterionic polymers or combinations thereof; and
    2) increase the concentration of microorganisms in the liquid mixture.
  18. 18. A method of reducing sludge formation in a membrane biological reactor, wherein the microorganisms consume organic material in the wastewater, and thus produce a liquid mixture comprising water, microorganisms, and slurry containing solids and suspended solids, and wherein the purified water is liquid. is separated from the mixture by filtration on a membrane, characterized in that
    1) adding to the liquid mixture an effective coagulating and flocculating amount of one or more cationic, amphoteric or zwitterionic polymers or combinations thereof; and ·· ·
    2) increase the duration of contact of the microorganisms with the wastewater.
    The proxy:
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    DISCLOSURE;
    HALF Banya
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    Figure 1
    Pofi PUBLICATIONS
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    MLLSS (mg / 1)
    25000
    20000
    15000
    10000
    Figure 2
    5000
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