MXPA06000081A - Cleaning of filtration membranes with peroxides - Google Patents

Abstract

The present invention relates toa process for cleaning a filtration membrane by adding one or more peroxide compounds to the influx. Preferably, one or more activators and/or reductants are added to the influx as well, in order to improve the performance of the peroxide compound. Optionally, one or more chelating agents and/or one or more surfactants can be used in said process.

Description

CLEANING OF FILTRATION MEMBRANES WITH PEROXIDES DESCRIPTIVE MEMORY The invention relates to a process for cleaning filtration membranes using peroxides. In many chemical manufacturing processes large volumes of water are used, including untreated raw water that is extracted from the immediate vicinity of the chemical plant. Said raw water contains many biologically active potential impellents, as well as other dissolved and suspended impellents. As a result, it is necessary to treat said gross water streams before introduction into the plant's processing systems. Furthermore, with the most demanding anti-pollution standards it has also become necessary to treat most of the waste water or effluent streams that leave the chemical plants, to control the biological oxygen demand (BOD), color, etc., before the water can be discharged. Sand filtration and gravity precipitation are techniques that are frequently applied in water purification treatments for solid-liquid separation, for wastewater and wastewater treatment, and for industrial water treatment. scrap Currently, different types of filtration membrane, such as precision filtration membranes or ultrafiltration membranes, are frequently applied for the removal of a wide variety of contaminants and impellers from water currents. When the water is subjected to the filtration treatment with these types of membrane, a high quality of treated water can be obtained. U.S. Patent 3,758,405, for example, describes a continuous method for removing and depositing colored particles that are present in aqueous effluents from Kraft pulping operations using ultrafiltration techniques. But a problem that arises when filtration membranes are used in these types of processes, is that suspended solids can clog the membranes, and an impenetrable layer can accumulate on their surfaces. Said impelling membranes will have a decreased filtration rate and / or an increased differential pressure between the membranes. Therefore, these membranes have to be cleaned gradually. A method for cleaning clogged membranes is described by examples in the U.S. patent. 4,740,308. This method comprises the steps of removing the membrane from the operation, generating in situ an oxygen singlet by performing a reaction on the clogged surface of the hydrogen peroxide membrane and an alkali metal or alkaline earth metal hypochlorite, and subsequently removing the society and the reaction products of the same, of the surface of the membrane. JP 2000117069 describes a sterilization and washing process for a membrane module of ultra or microfiltration of the hollow fiber type, which is used in the purification of raw water. In this procedure, an oxidation germicide containing peracetic acid, hydrogen peroxide and acetic acid is incorporated into the rewet water of the filtration membrane module, and the rewetting periodically takes place for 0.5-2 minutes every 0.3-2 hours. . In addition, after rewetting the filter membrane module, a rest period of 0.5-10 minutes is provided. A disadvantage of the membrane cleaning methods that were described earlier is during the operation, the membranes are gradually blocked. As a consequence, the flow rate gradually decreases and / or the differential pressure will gradually increase until the membrane becomes clogged to a degree where cleaning is necessary. If the speed of membrane obstruction could be decreased, or more preferably, if it were possible to prevent the membranes from becoming clogged, the average flow rate would be higher, resulting in lower process costs and increased process capacity. As wellOften the membranes have to be removed from the operation to clean them sufficiently. Therefore, it would be a great advantage if the membranes did not have to be removed from the operation as often, even more preferably, but had to be removed for none of the operation to clean them. Therefore, an object of the present invention is to provide an improved cleaning process for membranes that is economically more favorable. Particularly, an object of the present invention is to provide a preventive membrane cleaning process, wherein membrane clogging during processing is reduced. Surprisingly, it was found that by adding a certain peroxide in the influx, the flow remains high, which is economically very favorable. In addition, the membrane needs to be cleaned less frequently, and less aggressive cleaning products can be used. In more detail, the process according to the present invention for cleaning a filtration membrane, comprises dosing one or more water-soluble peroxide compounds, which are not essentially hydrogen peroxide, upon influx. The term "which are not essentially hydrogen peroxide" means that the total amount of the water-soluble peroxide compounds that are dosed at the influx, comprises at least one water-soluble peroxide compound that is different than is peroxide-different. of hydrogen. Preferably the total amount of the water-soluble peroxide compounds to be dosed at the influx comprises at least 0.1% by weight, preferably at least 0.5% by weight, more preferably at least 1% by weight, still more preferably at least 5% by weight, more preferably at least 10% by weight, and still more preferably at least 15% by weight, and more preferably at least 25% by weight of one or more soluble peroxide compounds in water other than hydrogen peroxide. At most, the total amount of the water-soluble peroxide compounds consists of 100% by weight of one or more water-soluble peroxide compounds other than hydrogen peroxide. Thus, the active substance (s) in the influx is (are) the organic (s) or inorganic (s) peroxide (s) according to the present invention, optionally prepared in situ , instead of hydrogen peroxide, which is less active than said inorganic or organic peroxides. It should be noted that the term "influx" used in this document means any aqueous stream, preferably one comprising contaminants. Preferably, the influx is an aqueous stream comprising organic compounds and / or biomass contaminants. Preferably, the method according to the present invention prevents organic contaminants from clogging the membrane. More preferably, clogging is prevented. However, it should be noted that the influx may also be a suitable aqueous stream to perform what is called a cleaning procedure in place, i.e., a membrane cleaning procedure wherein said membrane is temporarily removed from the operation to be subjected to a different influx comprising a rinsing solution. US 6,325,938 also relates to a process wherein the separation membranes are cleaned during use. Here, a special solid-liquid separation membrane assembly is applied, comprising at least one membrane module unit and a gas diffuser disposed below the membrane modules. Said gas diffuser generates bubbles, which upon reaching the surfaces of the membrane modules clean them, thus preventing the solid matter from depositing and obstructing the surfaces of the membranes. For further cleaning of the surface of the membrane, the membrane modules can come into contact with a cleaning solution comprising a detergent containing precarbonate and a bivalent iron salt. With this purpose, an inversion system or a liquid vessel system is preferably used, in which case the inversion system comprises placing the inner and outer portions of the separation membranes completely below the surface of said cleaning solution, and the system of liquid passage comprises passing said cleaning solution through the separation membranes in the same manner as a regular separation operation. However, a method for cleaning a filtration membrane according to the present invention is not described, wherein one or more water-soluble peroxide compounds are dosed into the infix. The term "peroxide compounds" as used in the present specification means both inorganic and organic peroxides. The peroxide compounds that are suitable for use in the process for cleaning filter membranes according to the present invention include any conventional inorganic or organic peroxide compound that is sufficiently soluble in water. The term "water-soluble" means that the peroxide compounds have a solubility in water of at least 0.01 ppm, but a reference of at least 0.1 ppm, more preferably at least 1 ppm, and more preferably of at least 5 ppm. When the peroxide compound, which is not essentially hydrogen peroxide, is dosed at the aqueous influx, contaminants that are present, preferably organic compounds and / or biomass contaminations, are oxidized or decomposed due to the reaction with the compound of peroxide, or with the reactive products produced by the peroxide compound that are present at the influx, so as to avoid clogging of the membrane or, preferably, to be completely inhibited. It was surprising to find that the presence of inorganic and / or organic peroxides according to the present invention produces an improved oxidative activity as compared to the activity of only hydrogen peroxide. It is anticipated that due to the presence of one or more carbon atoms in said inorganic or organic peroxides forming the oxidatively active substances at the influx, they have a much greater affinity for the organic contaminants and / or the biomass contaminants that are present. in the influx, which may be responsible for the obstruction of the membrane. Because of this larger affinity, these types of peroxide are more efficient in adhering to these contaminants, than hydrogen peroxide. As a result, these peroxides are more effective in preventing or inhibiting membrane plugging than hydrogen peroxide.

Preferably, one or more organic peroxide compounds are dosed in the influx. More preferably, the organic peroxide compound is selected from the group consisting of monofunctional peracids, alkaline earth metal salts of monofunctional peracids, polyfunctional peracids, alkaline earth metal salts of polyfunctional peracids, hydroperoxides, pre-esters, diacylperoxides, percarbonates, peroxydicarbonates, and salts of alkaline earth metal of percabonates. More preferably a monofunctional or polyfunctional peracid is used. Preferred inorganic peroxides include the alkaline earth metal salts or (tetra-alkyl) ammonium salts of peroxymono- and disulfates, and the alkaline earth metal or (tetra-alkyl) ammonium salts of perborates. Preferably, the alkali metal is sodium or potassium. Suitable monofunctional peracids that can be used include, but are not limited to performic acid, peracetic acid, perpropionic acid, perbutyric acid, perisobutyric acid, perlactic acid, perpentanoic acid, perhexanoic acid, perhpetanic acid, per-2-etiihexanoic acid, acid peroctanoic acid, mono-trans-succinic acid, mono-perglutaric acid, and perbenzoic acid. Another example is perpirubic acid (HOO-C (= O) -C (= O) -CH3). The polyfunctional peracids that can be used include, but are not limited to, permalonic acid, persuccinic acid, perglutaric acid, pertartaric acid, permaleic acid, perfumaric acid, peritaconic acid, and percyclic acid. The salts of said peracids can also be used. Examples include, but are not limited to, magnesium-monoperphthalic acid, magnesium-permaleic acid, and magnesium-monopercitraconic acid. In a particularly preferred embodiment magnesium-monoperoxyphthalic acid or peracetic acid is used as the peroxide compound. Examples of suitable hydroxy peroxides which can be used in the process according to the present invention are hydroxy peroxides of the general formula R-OOH wherein R is preferably an alkyl or alkylaryl group of C 1 -C 15 straight or branched, preferably a C1-C9 alkyl or alkylaryl group. Suitable hydroxy peroxides include, but are not limited to t-butyl hydroxy peroxide, t-amyl hydroperoperoxide, hydroperoxide 1, 1, dimethyl-3-hydroxybutyl, cumyl hydroperoxide, methyl ethyl ketone peroxide, methyl propyl ketone peroxide (any isomer), methyl butyl ketone peroxide (any isomer), acetylacetone peroxide, diacetone alcohol peroxide, acid hydroperoxy pyruvic (HO-C (= O) -C (= O) -CH2? OH), and hydroperoxy pyruvic acid ester (RO-C (= O) -C (= O) -CH2OOH). Examples of suitable presets include compounds of the general formula: wherein R is selected from the group consisting of -CH3; -CH (CH) 2; CH (CH2CH3) (CH2) 3CH3; -C (CH2) 2CH2); -C (CH 3) 2 (CH 2) 5 CH 3; -C (CH 3) 3; (CH2) 8CH3; -CH2 (CH2) 9CH3; -C6H6; and -CH2CH (CH3) CH2C (CH3) 3; and wherein R1 is selected from the group consisting of -C (CH3) 3; -C (CH 3) 2 CH 2 CH 3; -C (C6H3) 2 (C6H5); -C (CH3) 2CH2CH (OH) CH3 and -C (CH3) 2CH2C (CH3) 3. A particularly preferred pre-ester is t-butyl preacetate. Other peroxide compounds that can be used in the process according to the present invention include peroxides which they have a function of salt or water-soluble substituents, such as esters of ethylene or propylene, polyethylene or propylene glycol, polyethylene-propylene glycol copolymers, or mixtures thereof. The percarbonates and the salts of alkaline earth metal can also be used as the peroxide compound in the process according to the present invention, these may be mono-, bi-, or polyfunctional. Examples of suitable percarbonates include the compounds of the general formula: O R2 > L > X wherein R2 is methyl, ethyl, linear fatty acid alkyl, branched fatty acid alkyl, and wherein X is hydrogen or an alkaline earth metal. Without However, these compounds are less preferred.

It should be understood that the word "dose" is used to describe the step of adding the one or more peroxide compounds in the influx to prevent blocking of the membrane. The dosage can be done continuously, which means that during a certain period the compounds are continuously administered at the influx. The dosage of the peroxide compound (s) to the influx can also be made intermittently during the operation, in which case the person skilled in the art will be able to select the optimum interval times and the optimal amounts of the compound (s) of peroxide that will be dosed by routine experimentation. A combination of these techniques is also possible. Examples of a combination of such techniques include, for example, a process in which they are first added continuously into the peroxide compound (s), then the administration is stopped, and then again (are) added (s) continuously . Preferably the (the) peroxide (s) is / are dosed continuously or intermittently from the beginning of the procedure. An intermittent dosing operation is more preferable. The peroxide compound (s) can be dosed to the influx in any conventional manner. Preferably they are dosed at the influx in an aqueous solution. In addition, in a preferred embodiment of the present invention, a mixture of hydrogen peroxide and one or more organic peroxide compound according to the invention, preferably dissolved in water, is dosed at the influx. But organic peroxide compound (s) can also be exerted as a suspension or emulsion in water, preferably, the peroxide compound (s) used is / are biodegradable ( s).

It should also be understood that the phrase "dosing at the influx one or more water-soluble peroxide compounds" as used in the present specification means that it includes the step of adding hydrogen peroxide and one or more peroxide precursors to the influx to prepare the one or more water-soluble peroxide compound (s) according to the invention in situ. "peroxide precursor" means any compound that can be converted into a suitable water-soluble peroxide compound by reacting with hydrogen peroxide. For example, when hydrogen peroxide and a suitable carboxylic acid or anhydride are dosed under the influence, the corresponding peracid is formed. Preferably, the hydrogen peroxide and the peroxide precursor are pre-mixed before dosing. A preferred example is the dosage of acetic anhydride and hydrogen peroxide to the influx under the formation of peracetic acid, catalyzed with a trace of acid, or the dosage of methyl ethyl ketone and hydrogen peroxide upon influx under the formation of Int. Al. HOOC (CH3) (CH2CH3) OOH, catalyzed by a trace of acid. The acid in the mixture can also function as an agent against the formation of oxide. Normally the total amount of the compounded compound (s) of peroxide triturated at the influx is less than 1,000 mg per liter of influx. Preferably less than 500 mg and more preferably less than 50 mg of the peroxide compound (s) which are dosed per liter of influx. The concentrations of the peroxide compound (s) of more than 1,000 mg per liter of influx are also permissible, but are less preferred. Normally more than 0.1 mg, preferably more than 1 mg and more preferably more than 5 mg of the compound (s) per liter of influx are dosed. However, if the process is a cleaning procedure in place as indicated above, preferably the total amount of the peroxide compound (s) that is dosed at the influx is from 1 to 100 times the aforementioned amounts. Preferably, the total amount of the peroxide compound (s) that is dosed at the influx is more than 100 mg of the dosed peroxide compound (s) per liter of influx. Preferably less than 2, 000 mg, more preferably less than 1,500 mg of the peroxide compound (s) that are dosed upon influx. Preferably, one or more activators are dosed at the influx to improve the performance of the peroxide compound. Preferably the activator is a metal salt, wherein the metal ion has an adequate oxidation potential against the peroxide compound. In a preferred embodiment of the present invention, the metal is selected from the group consisting of Fe, Mn, Cu, Ni, Cr, V, Ce, Mo and Co. In another preferred embodiment, a compound containing a group is employed Not me. Suitable amine compounds for use in the process according to the present invention include dimethyl aniline, diethyl aniline, dimethyl toluidine, aromatic polymeric amines, quaternary amines, nitroxides, and amine salts. In another preferred embodiment of the present invention, the activating metal element is complexed with, or incorporated into, the peroxide compound.

Normally the amount of the activator (s) that is dosed at the influx is less than 1,000 mole% per liter of influx, based on the total amount of the peroxide compound that is present per liter of influx. Preferably, less than 300 molar%, and more preferably less than 150 molar per liter of influx, is dosed based on the total amount of moles of the peroxide compound that is present per liter of influx. Normally more than 0.1 mole%, preferably more than 1 mole%, and more preferably more than 10 mole% of the activator (s) are used per liter of influx, based on the total amount of moles of the peroxide compound present per liter of influence. In the process according to the present invention, reducing agents can be used to influence the potential oxidation of the metal ions. Preferred reductants include, but are not limited to, ascorbic acid, citric acid, tartaric acid, oxalic acid, sodium formaldehyde sulfoxylate, and bisulfite salts. Normally the total amount of the reductant (s) that is dosed at the influx is less than 1, 000 mol% per liter of influx, based on the total amount of moles of the peroxide compound that are present per liter of influx. Preferably less than 300 mole%, and more preferably less than 150 mole% per liter of influx, is dosed based on the total amount of moles of the peroxide compound that are present per liter of influx. Normally more than 0.1 mole%, preferably more than 1 mole%, and more preferably more than 10 mole% of the reductant (s) are used per liter of influx, based on the total amount of moles of the peroxide compound that they are present per liter of influence. When a reducer (s) is used, the amount of activator (s) can be reduced approximately 10 times, more preferably on the 0-20% molar scale. If the water in the influx contains a sufficient amount of a suitable metal salt as an activator, as an iron source, the addition of one more activators to the influx may not be necessary. Preferably one or more reducing agents are metered in to influence the performance of the peroxide compound. Preferably the reductant is a compound that reduces the activator to an adequate oxidation potential against the peroxide compound. In a preferred embodiment of the present invention, the reductant is selected from the group consisting of bisulfites, sulfites, phosphides, oxalic acid, ascorbic acid, isoascorbic acid, sodium formaldehyde sulfoxylate. More preferably, ascorbic acid is used with the reductant. Regardless of the dosing procedure for the peroxide compound (s), the activator (s) and / or the reductant (s) can be dosed continuously, intermittently or by a combination of these techniques. An intermittent dosing procedure is preferable. In the intermittent dosing process it is possible to add the peroxide compound (s) and the activator (s) and / or the reductant (s) at the same time. However, it is preferable to add them to the influx successively at certain intervals or at different points in the influx supply. There may also be some time between dosing intervals without any dosage. In a particularly preferred embodiment of the present invention, one or more activators and / or one or more reductants are dosed continuously under the influence for a certain period, and after the addition has stopped, one or more peroxide compounds are dosed in the form continues to influence for a certain period, and then this procedure is repeated. The term filtration membrane that is used throughout this specification can be applied to any conventional polymeric and / or ceramic filtration membrane. In general, these membranes are characterized by their MWCO (molecular weight cutoff) and / or their retention values for inorganic salts and / or small organic molecules. Membranes suitable for use in the process according to the present invention include reverse osmosis membranes (smaller pores of 0.11 nm), nanofiltration membranes (from 0.8 nm to 9 nm pores), ultrafiltration membranes (pores from 3 nm to 100 nm), microfiltration membranes (pores from 50 nm to 3 μm) and particle filtration membranes (pores from 2 μm) up to 2 mm). The person skilled in the art can select an appropriate membrane based on general knowledge. Particularly preferred membranes are reverse osmosis membranes and nanofiltration membranes. Preferably, the process according to the invention is not used to clean a contaminated semipermeable membrane that is used in a pervaporation or vapor permeation process, wherein the water is transported through said semipermeable membrane. In the process according to the present invention it is also possible to add one or more chelating compounds, optionally in combination with one or more activators. Suitable chelating agents include, but are not limited to carboxymethyleneamino derivatives such as NTA (has been nitriloacetic), EDTA (ethylenediamine tetraacetic acid), DTPA (diethyltriamine pentaacetic acid), methylenephosphonated amine derivatives such as ATMP (trimethylene phosphonic acid), EDTMP (acid ethylenediamine-tetra-methylene phosphonic acid), citric acid, gluconate, glucoheptanoate, lactate and sorbitol. It is also possible to add one or more surfactants, again optionally in combination with one or more activators. Suitable surfactants include conventional cationic, anionic and nonionic surfactants. For example, alkaline earth metal salts of fatty acids, mono-, bi- and poly-saccharine ammonium salts, and fatty amine derivatives can be applied again, the chelating compound (s) and / or the ) | surfactant agent (s) can be dosed on inflow continuously, intermittently or by a combination of these techniques, regardless of the dosing procedure for the one or more peroxide compound (s) and / or the one or more activators. Preferably, the chelating compound (s) and / or the surfactant agent (s) are dosed intermittently upon influx. The chelating compound (s) and / or the surfactant agent (s) is (are) used in conventional amounts. Other additives that can be dosed at the influx include conventional agents against scale formation. In a particularly preferred embodiment according to the present invention, in addition to the one or more peroxide compounds, one or more activators, one or more reducing agents, one or more chelating compounds and / or one or more detergents are added to the influx. If desired, one or more conventional pH regulators may also be added to the influx, as long as they do not adversely affect the cleaning process according to the present invention. Preferably the additives are present in the formation of the peroxide, the activator (s), the reductant (s), or in the premix of hydrogen peroxide and peroxide precursor. The present invention is understood by means of the following non-limiting examples.

EXAMPLE 1 An influx comprising organic contaminants and biomass contaminants was subjected to a filtration procedure using a tubular ultra filtration membrane of the UFC M5 ID 0.8 mm type, the membrane material was polyvinyl / pyrrolidone. A constant transmenbranal pressure of 5.0 bar was applied. At the beginning of each experiment, clean water flow (CWF) was determined using demineralized water. The influx was filtered, and the decrease in flow (= cauda!) Was measured (see figure 1). Starting from t = 0 s, mg / l of Trigonos® 44B ex Akzo Nobel was continuously added to the influx. The flow was measured until it decreased from 250 l / m2. h at 170 l / m2. h from t = 0 s to t = 400 s. After 400 s, 1 mole% of Fe (SO) 2 was added, based on the amount of the peroxide compound present per liter at the influx, over a period of 250 s (from t = 400 s to t = 650 s). In figure 1 it can be seen that the flow increased from approximately 170 l / m2. h at 200 l / m2. h. It was observed that the flow decreased from 200 l / m2. h of 125 l / m2. h during t = 650 s at t = 1, 350s. When 1 mol% of Fe (SO) 2 was added again, based on the amount of the peroxide compound, over a period of 250 s (t = 1, 350 sat = 1, 600 s), an increase was observed in the flow of 125 l / m2. h at 150 l / m2. h.

EXAMPLE 2 An influx comprising organic contaminants and biomass contaminants was subjected to a cross-flow filtration method using a thin film, composite, capillary nanofiltration membrane of the NF50 M10 type, the membrane material was polyamide / polyether sulfone. A constant transmenbranal pressure of 3.0 bar was applied and the cross flow along the membrane was 0.4 m / s (laminar flow). At the start of each experiment, clean water flow (CWF) was determined using demineralized water. Subsequently, the influx was filtered for 30 minutes, and the decrease in flow (= flow rate) was determined. To prevent the membrane from becoming contaminated, the following compounds were continuously dosed at said influx: -1 mg per liter of methyl ethyl ketone peroxide (MEKP) influx; -1 mg per liter of influx of trigonox® 44B ex Akzo Nobel N.V .; Y - a formulation that included Water: 17.2 ± 0.1% m / m H2S04: 1.0 ± 0.1% m / m Acetic acid: 43.8 ± 0.2% m / m Peracetic acid: 33.6 ± 0.2% m / m H202: 48 ± 0.1% m / m, in such amount that 1 mg or 0.1 mg of peracetic acid was dosed at the influx. Again, the decrease in flow was determined. In addition, 1 mol% was continuously metered, based on the total amount of the peroxide compound (s), of the activator in the influx. Said activator was Fe (II) sulfate. The results of these experiments are shown in table 1.

TABLE 1 It was found that when 1 mol% of Fe (S0) was used as activator in addition to 1 mg of methyl ethyl ketone peroxide, 1 mg of Trigonos® 44B, or 1 mg of a peracetic acid formulation per liter of influx, the decrease in the flow (= flow) is significantly lower than when only the peroxide compound is used. Figure 2 shows the decrease in flow over time for the experiment described above, using said formulation comprising peracetic acid, optionally in combination with an Fe activator, where: It shows the decrease in the flow of the blank procedure, ie , without the addition of a peroxide compound to the influx; - - Shows the decrease in the flow when a quantity of the aforementioned peracetic acid formulation is dosed continuously under the influence, introducing 1 mg of peracetic acid per liter of influx; y It shows the decrease in flow when, in addition to the addition of 1 mg / l of peracetic acid, it is continuously dosed at the 1% molar influx of Fe (SO4). As can be seen in Figure 2, the continuous dosing of the peracetic acid formulation to the influx has an advantageous effect on the flow during the first 400 seconds of the procedure. However, when the Fe activator is continuously dosed to the influx in addition to the peracetic acid formulation. The flow is still significantly greater throughout the procedure.

Claims (12)

NOVELTY OF THE INVENTION CLAIMS

1. - A process for cleaning a filtration membrane by dosing at the influx one or more water-soluble peroxide compounds, which are essentially not hydrogen peroxide.

2. The method for cleaning a filtration membrane according to claim 1, further characterized in that one or more activators and / or one or more reducers are also dosed upon the influence.

3. The process for cleaning a filtration membrane according to claim 2, further characterized in that the activator comprises a Fe salt, a salt of Mn, a Cu salt, a Ni salt, a Co salt or a amine compound, and preferably, said activator comprises a Fe salt.

4. The process for cleaning a filtration membrane according to claim 2, further characterized in that the reductant is selected from the group consisting of oxalic acid, a salt of bisulfite, ascorbic acid, isoascorbic acid, and sodium formaldehyde sulfoxylate.

5. The process for cleaning a filtration membrane according to any of the preceding claims, further characterized in that the peroxide compound is selected from the group consisting of monofunctional peracids, alkaline earth metal salts of monofunctional peracids, polyfunctional peracids, salts of alkaline earth metal of polyfunctional peracids, organic hydroperoxides, pre-esters, percarbonates, alkaline earth metal salts of percarbonates, alkaline earth metal or ammonium salts of persulfates, and alkaline earth metal or ammonium salts of perborates.

6. The method for cleaning a filtration membrane according to claim 5, further characterized in that the peroxide compound is selected from the group consisting of peracetic acid, perpropionic acid, monopersuccinic acid, monoperglutaric acid, acetyl ketone peroxide, and acid monoperoxyphthalic magnesium.

7. The process for cleaning a filtration membrane according to any of the preceding claims, further characterized in that one or more chelating compounds are added to the influx.

8. The process for cleaning a filtration membrane according to any of the preceding claims, further characterized in that one or more surfactants are added to the influx.

9. The process for cleaning a filtration membrane according to any of claims 1 to 6, further characterized in that one or more activators, one or more reducing agents, one or more chelating compounds, and one or more agents are added to the influx. surfactants.

10. The process for cleaning a filtration membrane according to claim 2, further characterized in that the activator and / or reducer is added intermittently to the influx.

11. The process for cleaning a filtration membrane according to any of the preceding claims, further characterized in that the peroxide compound is added intermittently to the influx.

12. The method for cleaning a filtration membrane according to any of the preceding claims, further characterized in that the membrane is selected from the group consisting of a reverse osmosis membrane, a nanofiltration membrane, an ultrafiltration membrane, a membrane of microf iltration and a particle filtration membrane.