CN1248972C - Method for treating circulating water and composition used therefor - Google Patents

Abstract

A method of purifying and recycling waste water from a domestic laundry process, preferably for use in a washing or rinsing step. The process uses flocculants to form floes and separate out, thereby removing the soil. The invention also relates to water purification compositions comprising primary and secondary flocculents which may be added simultaneously or sequentially, kits for providing unit doses of flocculents, apparatus for separating floes from treated water, and detergent compositions comprising flocculents.

Description

Method for treating circulating water and composition used therefor

Technical Field of the Invention

The present invention relates to products and methods required by the user to be able to reuse contaminated wash water, such as sewage from washing processes, especially laundry processes.

Background technique

In many countries, household washing practices are labor intensive and require large amounts of water during the washing and cleaning stages. This is especially true of the laundry process. Often the infrastructure does not allow the use of fully automatic fill/drain machines, water must be collected manually, and wastewater disposal is even more problematic. This water can be recycled in a conventional manner using common wastewater treatment methods (sewage systems) or it can be discharged directly into waterways.

Water purification methods are well known in the prior art, for example GB2004535A describes a water clarification method in which polyelectrolytes are used as flocculants. These polyelectrolytes can be nonionic, anionic or more preferably cationic. In addition to the addition of polyelectrolytes to aid coagulation, coagulants such as granular minerals may also be used. The treatment method is said to be suitable for treating waterways, such as river water.

GB1391578 also relates to a method and composition for flocculating suspended solids. Especially suitable for removing particles with a diameter of less than 10 microns. The patent is specifically directed to drinking water as a municipal water supply. This patent describes that water can be well clarified by pre-mixing a certain proportion of water-soluble cationic polymers with water-soluble non-ionic polymers.

SU891575 highly purifies turbid raw water in two treatment stages, filtration after flocculation with aluminum sulfate, and treatment with polyacrylamide. SU1085942 Purifies wastewater from drilling operations, which contains mud, petroleum products, polymers and surfactants. Water is purified using a mixture of polyacrylamide, polyvinylamine polyelectrolytes, and alkali metal chlorides. JP06071112, JP06309110, JP54073464, JP76042078 and JP51093550 also relate to methods of flocculation for water purification.

In FR2466438, a method of purifying laundry water is described without overloading the sewage treatment plant and without directly adding components such as surfactants and phosphates to the river. The flocculant used is aluminum sulfate and anionic polyelectrolyte.

US5807487 Treats wastewater from laundromats. The water is first stored in a homogenization tank and then transferred to a second tank where the water is acidified to a pH of no less than 6.5. Then, for further flocculation, a flocculant, preferably polyaluminum chloride, is added to the second tank, and the pH value in the second tank is adjusted not lower than 5.0, thereby obtaining treated water and separated sludge.

GB1543411 describes a method for recycling waste water containing synthetic detergents. First, a water-insoluble surfactant is added to form an emulsion with a synthetic detergent. The emulsion is then broken by adding flocculants or by electrochemical or ultrafiltration methods.

However, all these methods described above relate to industrial methods and do not solve the specific problems of the users presented above.

SUMMARY OF THE INVENTION

The present invention provides a method of treatment of domestic laundering process water comprising separating washed items from waste water from washing and/or cleaning steps containing organic and/or inorganic soils and synthetic detergents, contacting the waste water with a flocculant system thereby To form flocs, the flocculant system includes a primary flocculant selected from polyvalent cations and polyethyleneimines or mixtures thereof and a secondary flocculant selected from anionic and nonionic polyelectrolytes or mixtures thereof, and removes flocs from wastewater Separation produces purified water, which is reused, wherein an alkali source pH regulator is added to the wastewater, and at least the main flocculant is added to the wastewater before adding the alkali source.

According to another aspect of the present invention, there is also provided a method of treating water in a household washing process, comprising separating washed items from waste water from washing and/or cleaning steps containing organic and/or inorganic dirt and synthetic detergents, so that Wastewater is contacted with a flocculant system to form flocs, said flocculant system comprising a primary flocculant selected from polyvalent cations and polyethyleneimines or mixtures thereof and a secondary flocculant selected from cationic polyelectrolytes and mixtures thereof, The flocs are separated from the waste water to produce purified water, which is reused, wherein an alkali source pH regulator is added to the waste water, and at least the primary flocculant is added to the waste water before the alkali source is added.

Preferably said domestic laundering process is a laundry process. In a preferred method of the invention, the purified water is still reused in domestic laundering processes, such as dishwashing, laundry or personal cleaning, preferably in laundry processes, both washing and/or cleaning. Preferably reused in the washing step. The washing and/or cleaning water is purified and can be recycled for multiple times.

The present invention also includes a water purification kit for domestic use comprising at least one unit dose of flocculant, a unit dose comprising 0.5 to 250 g of flocculant and optionally means for removing floc from treated water.

The present invention also includes a water purification kit for domestic use comprising a water purification composition comprising a flocculant, means for providing a unit dose of flocculant, and optionally means for removing floe from wastewater.

In another embodiment of the present invention, there is also provided a washing vessel for domestic laundering, wherein waste water from the washing and cleaning steps of the washing process is purified by removing particulate solids, said washing vessel comprising an inner layer and an outer The first layer forms a continuous surface so that the wash water is contained in the wash container during the washing process, and the second layer is provided with a screen capable of passing the water while retaining particulate solids.

According to another aspect of the present invention, a detergent composition containing a sub-flocculant is also provided.

Preferably the secondary flocculant is present in the detergent composition in an amount such that after the laundry items have been washed and removed, the remaining amount of the secondary flocculant is sufficient to promote flocculation when the primary flocculant is added.

Detailed description of the invention

Adding flocculants: water treatment steps

After washing clothes and/or other items in an aqueous solution containing detergent, or after adding rinse water for washing, it is necessary to separate the spent washing liquid or wash water from the washed items. The washing process can be any household washing process such as personal bathing, dish washing, hard surface cleaning or laundry. Generally speaking, the washing process is a laundry process, and the waste water needs to be separated from the wet clothes. In addition to detergent components, wastewater also contains granular and/or colloidal dirt, which is organic and/or inorganic. In the method of the present invention, the waste water can be separated by removing the washing items such as wet clothes from the water, so that the subsequent water treatment can be carried out in the washing vessel, or the liquid can be extracted and collected in the treatment vessel for treatment.

The flocculant system is then added to the wastewater in solid form, such as a powder or tablet, or in liquid form, such as an aqueous solution, or in the form of a solid-liquid mixture. The primary and secondary flocculants can be added to the wastewater simultaneously or sequentially.

flocculant

The flocculant includes a flocculant system composed of a primary flocculant and a secondary flocculant. The primary flocculant is selected from polyvalent cations and polyethyleneimines. For example, multivalent cations are salts, including polymer salts such as aluminum, divalent magnesium, or ferric iron. Preferred examples are aluminum salts. A preferred source of aluminum ions is aluminum chloride. Another preferred source of aluminum ions is aluminum sulfate. Another preferred source of aluminum ions is polyaluminum chloride. Another preferred source of aluminum ions is aluminum sulfate silicate. Mixtures of more than one source of aluminum are also suitable. Hexavalent iron ions (ferrate ions) may also be preferred because when dissolved in water, ferric ions and peroxides are formed, thereby adding some bleaching effect in the reused water, which is useful when reused as a laundry step. The advantage of this effect is very significant. However, iron compounds are not preferably used due to discoloration of water due to the presence of ferric ions.

Preference is given to using polyvalent metal aluminum ions. Both anhydrous and hydrated salts can be used, but hydrated salts are preferred. In particular aluminum sulfate and aluminum chloride have been found to be particularly beneficial as they rapidly form flocs and float to the surface of the wastewater where they can be easily removed. A particular improvement of the invention consists in the use of aluminum hydrate salts as flocculants. Since it was found that AlCl ₃ .6H ₂ O and Al ₂ (SO ₄ ) ₃ .16H ₂ O can promote the floating of flocs to the water surface well when treating household washing wastewater, especially laundry liquid, it is preferable to use AlCl ₃ . 6H ₂ O and Al ₂ (SO ₄ ) ₃ .16H ₂ O. In one embodiment of the present invention, the main flocculant is preferably a mixture of aluminum sulfate and aluminum chloride. Hydrated salts are especially preferred. The mixture of aluminum sulfate and aluminum chloride salt comprises 5-60% by weight, preferably 15-35%, more preferably 20-30% of aluminum sulfate, and 40-95% by weight, preferably 65-85%, More preferred is 70-80% aluminum chloride. When polyethyleneimine is contained in the main flocculant, the molecular weight of the applicable material is not as high as that of the polyelectrolyte mentioned below, such as not more than 5×10 ⁶ , preferably not more than 1.5×10 ⁶ , more preferably not more than 1× 10 ⁶ .

The applicable secondary flocculants are organic polyelectrolytes, and in one aspect of the present invention, high molecular weight cationic polymers are preferably used. However, according to another preferred embodiment of the present invention, the secondary flocculants are preferably anionic and/or nonionic polyelectrolytes.

A number of suitable synthetic cationic polymer materials can be used, these are usually high molecular weight polyamides or polyamines. Especially preferred are polyacrylamide derivatives. The molecular weight (Mw) is preferably in the range of 10 ⁵ to 10 ⁷ according to the measured viscosity. The molecular weight is preferably above 4×10 ⁶ , more preferably above 5×10 ⁶ . The molecular weight is preferably around 6 x 10 ⁶ or above 6 x 10 ⁶ .

Cationic polyelectrolytes are preferably polymers having a cationic activity (percentage of the number of pendant groups that react to provide cationic groups) greater than 20%, more preferably greater than 30%, most preferably greater than 40 or 60%. It is particularly preferred that the molecular weight of the material is above 4×10 ⁶ and the cationic activity is greater than 40%. Suitable materials can be prepared by copolymerization of acrylamide and quaternary ammonium polyacrylamide. Examples of suitable polymers include Zetag 89, Praestol 611BC, Calfloc 1552, 1506 and 1508, and Polymin KP97 (trade name).

The use of nonionic and anionic polymers as flocculants is well known in the prior art. A preferred process of the present invention is that the secondary flocculants include nonionic and/or anionic flocculants. Applicable anionic or nonionic polyelectrolytes are generally water-soluble High molecular weight acrylamide polymer. These may be methacrylamide polymers, but are preferably acrylamide polymers. It is also possible to copolymerize other monomers with (meth)acrylamide, so that it has anionic properties. The preferred polymer is high molecular weight polyacrylamide, with a molecular weight of more than 1 million, usually 2 million to 30 million Between, the usual intrinsic viscosity (dl/g) is 5 or more, usually 8 or more. For very high molecular weight polymers, which are also suitable, the intrinsic viscosity can even be greater than 10, usually between 12 and 16 or higher. Preferred polymers have a solution viscosity (measured on a 1% solution in deionized water in a Fann viscometer at a shear rate of ^5.11 sec at 25°C) of at least 350 cp s, more preferably at least 500, or Even at least 1000cps. The molecular weight is preferably greater than 2×10 ⁶ but not greater than 20×10 ⁶ .

Suitable anionic polyelectrolytes have an anionic activity (percentage of the number of side groups that react to provide anionic groups) greater than 5%, or greater than 10%, or even greater than 20%. Particularly preferred examples include anionic and nonionic polyacrylamides such as the Magnafloc ^™ series from Allied Colloids. This flocculant is preferably high molecular weight, such as Magnafloc 155 and/or Magnafloc 351, or ultrahigh molecular weight, such as Magnafloc 919.

In a preferred aspect of the present invention, a pH regulator can be added to the wastewater before or at the same time as the main flocculant, and the pH regulator is an acid source. The addition of an acid source is preferred since the polyvalent cations initially react with anions such as phosphates, silicates and carbonates present in the wastewater, since the addition of an acid source can reduce the amount of primary flocculation used. The amount of acid added to the wastewater is preferably such that the pH of the wastewater is about 2.5 to 7. A suitable acid source may be any acid, but carboxylic acids such as dicarboxylic or polycarboxylic acids are particularly preferred. Suitable examples include malic acid, citric acid, tartaric acid, maleic acid, glutaric acid, adipic acid, succinic acid and mixtures thereof. Polymeric carboxylic acids include polyacrylic acids and their copolymers.

According to a particularly preferred embodiment of the present invention, especially when the secondary flocculants include anionic and nonionic polyelectrolytes, an alkaline source pH regulator is also added to the wastewater. Suitable alkaline source pH adjusters are described in detail below. However, a particularly preferred source of alkalinity would be a carbonate buffer, such as sodium or potassium carbonate. It is best to add at least the primary flocculant to the wastewater before adding the alkali source. This can be achieved by dosing the alkali source after dosing the flocculant system or after dosing the primary flocculant alone. However, it is preferred to add at the same time as the primary flocculant, preferably also with the secondary flocculant, the form of the primary flocculant and the source of alkali is selected such that the primary flocculant is released into the wastewater faster than the source of alkali For example, the primary flocculant is added as a solution that releases rapidly into the wastewater. However, it is more preferred that the flocculant is dosed in powder/granule form. The above-mentioned first release can be realized by making the particle size of the main flocculant added smaller than that of the alkali source, for example, the geometric mean size of the alkali source particles is at least 25 microns larger than the geometric mean size of the main flocculant particles, or even at least 50 microns larger, Or at least 75 microns larger. Additionally, a slow release source of alkalinity may be provided, the outer surface of which is coated or coated with a water soluble or friable coating which provides a delayed release of the source of alkalinity.

As used herein, the term "geometric mean particle diameter" refers to the geometric mass median diameter of a group of discrete particles measured using known mass-based particle size measurement techniques, preferably dry sieving. Applicable sieving methods are based on the IS03118 (1976) method. A suitable device is a Ro-Tap Test Sieve Shaker Model B utilizing an 8 inch screen size. As used herein, the term "geometric standard deviation" or "spacing" of a particle size distribution refers to the geometric width of the best-fit logarithmic nominal function to the above-mentioned particle size data, which can be calculated by the ^50th percentile of the cumulative distribution Expressed as the ratio of the diameter at the 84.13th percentile divided by the diameter at the 84.13th percentile (D _84.13 /D ₅₀ ); see Gotoh et al., Power Technology Handbook, pp.6-11, Marcel Dekker 1997.

After the flocculation reaction is completed and the alkali source is dissolved, the pH value of the wastewater containing flocs is preferably 4.0-7.0, most preferably 4.5-6.5.

The addition of an alkalinity source may have other benefits as the alkalinity source reacts with polyvalent metal ions or other acid sources present in the wastewater to generate gas bubbles. This aids in the flotation of the floe.

When cationic polyelectrolytes are used, the water after removing flocs also contains higher concentrations of multivalent metal ions. Addition of a source of alkalinity is also useful from the standpoint that addition of a source of alkalinity may facilitate precipitation to remove high concentrations of multivalent metal ions. In some cases, removal of Unnecessary high-concentration ions can replace the direct addition of alkali sources.

In a preferred aspect of the present invention, the primary flocculant and the secondary flocculant are added to the wastewater at the same time. In addition, the main flocculant is added before the auxiliary flocculant. The two components can be metered in at the same time, but the main flocculant and the secondary flocculant are respectively selected in their respective forms, so that the primary flocculant is dispersed into the wastewater preferentially over the secondary flocculant.

Another more preferred way is that the secondary flocculant can be a detergent ingredient that is present throughout the wash, so that in the cycle step, after the wash items are separated, only the primary flocculant and optionally other ingredients such as pH adjustment are added Flocculants and/or foaming systems, or by adding these components and low concentrations of secondary flocculants, flocculation can occur. The present invention therefore also includes a method in which the detergent ingredients include a secondary flocculant used in domestic laundering, the primary flocculant is added to the waste water after the wash items have been separated, thereby producing flocs, and then The flocs are separated from the wastewater so that the wastewater can be reused.

It is preferred to stir the flocculant system when it is added to the wastewater, or to stir the flocculant after it is added to the wastewater. The mixture can be stirred mechanically or more commonly manually, because the stirring can promote the rapid diffusion of the flocculant into the wastewater to promote the flocculation. The formation of material, so stirring is preferably vigorous stirring. When adding the flocculants sequentially, stirring is preferably carried out after each flocculant component is added. The inventors have found a mixture which is particularly effective and rapid in forming flocs of high strength, even with small amounts of flocculant, relative to the amount of soil present in the wash liquor.

The amount of flocculant required depends to some extent on the fouling content of the wastewater to be purified. Typically, the required total flocculation dosage is from 0.05, or from 0.1, or even from 0.5 g/l to 20 g/l, or below 10 g/l, or even below 5 g/l relative to the water to be purified.

If the primary flocculant includes polyvalent metal salts, the amount used is generally 0.005 to 10 g/l, preferably 0.1 to 10 g/l, relative to the water to be purified. The standard volume of treated wastewater can be from 2 to 200 or from 3 to 70 or 4-40 liters. However, when washing is carried out in a machine, the volume of wastewater to be treated is somewhat larger, eg 10-100 liters, often around 20 to 70 liters, more usually around 25 to 40 liters.

Therefore, when treating such wastewater, especially when using a machine, the preferred dosage of multivalent cation salt is usually 40-100g, better 50-120g, most preferably 60-100g.

When the waste water comes from the hand washing step, the preferred flocculant dosage is 0.5 to 20 g/l, usually greater than 2 g/l, or greater than 3 g/l, or even greater than 5 g/l.

The dosage of the auxiliary flocculant, which may be cationic, anionic or nonionic, is preferably 0.001-1 g/l of water to be purified. In particular, the polymeric material is charged in an amount of from 0.01-2.0 g/l, or even 0.1-0.8 g/l. Typically, the polymeric material is added in solution, for example at a weight percent concentration in the aqueous solution of 0.1-10%, or even 1-10% by weight of the aqueous solution. Therefore, for a standard waste water volume of about 30 liters, use 10-200ml or 10-100ml of a solution of 1% polymeric flocculant components, preferably 20-50ml, and for high-concentration solutions, use relatively low volume, or higher volumes at low concentrations.

In addition to adding flocculant ingredients mentioned above, floc builders can also be added to wastewater. Suitable floc builders are, for example, clay and/or talc, and/or synthetic zeolites, natural zeolites, especially long-fiber cellulose and mixtures thereof. Other optional additives in the water treatment step are dye fixing polymers which can be used to collect any residual dye present in the wastewater for removal. Said additives are also pH adjusters, deodorants, fragrances, antibacterial agents, bleaching agents, dyes, foam suppressors. During floe formation, the dye-fixing polymer co-precipitates with other precipitates, or becomes part of the floe.

The flocs formed in the process of the present invention are very strong and therefore do not substantially break up when they are separated from wastewater. In addition, the flocs formed preferably include a high proportion of large flocs, such as at least 60%, more preferably at least 80% of the flocs having a diameter greater than 250 microns, preferably greater than 400 microns, more preferably greater than 750 microns, even greater than 1000 microns. %. The floe diameter is usually no greater than 5000 microns, or up to 2000 microns. It is particularly preferred that at least 70% by weight of floe has a size between 1200 and 1900 microns. When waste water containing flocs flows into the sieve, it is measured according to the proportion of flocs flowing through or trapped on the sieve with limited mesh size. Larger flocs are preferred because they separate quickly from clean water.

Separation of flocs

The flocs formed can be separated from the waste water by any of the conventional methods as will be described in detail below.

If it is desired to float the formed flocs to make them easy to remove, in addition to adding flocculant components for purification to the wastewater, it is also necessary to supplement with gas generation means. It is possible to provide a gas generating device that simply bubbles into the waste water when forming flocs. In addition, a foaming system can be provided by gas-generating reactions, such as the in-situ reaction of acids and bases present in wastewater to generate carbon dioxide. Such acid-base reactants can also be added to the wastewater, for example with a flocculation system, or these reactants are already present in the wastewater. Specifically, the main flocculants are polyvalent metal ions, and these components can provide acid sources. Furthermore, an acid source, such as a carboxylic acid, eg a dicarboxylic acid or a polycarboxylic acid, may be added to the wastewater. Suitable examples include malic acid, citric acid, tartaric acid, maleic acid, glutaric acid, adipic acid, or succinic acid or mixtures thereof, alkali sources such as carbonates, bicarbonates, sesquicarbonates or mixtures thereof . Usually alkali metal carbonates are used. These components can be added to the waste water in any relative proportions that produce gas, and they are usually provided in stoichiometric ratios. Foaming systems can also be used to ensure that the resulting clean water for recirculation has the proper pH.

Reuse of purified water

After the flocs are separated, the remaining water is pure water that can be reused. A preferred aspect of the invention resides in the recycling of water for the washing or cleaning step of the clothes. According to the specific use of purified water reuse, adjust the pH value of the purified water. It is best to choose the flocculant so that the purified water has the desired pH value for reuse, but for some special reuse, a pH regulator can also be added to produce the desired pH value. For example, for a wash step, if fabric conditioners are to be used, it is desirable for the clean water to have an acidic pH of less than 7, typically 2-7 or 2-6. However, if the pH is too high or too low, an acid or base, respectively, can be added prior to adding the fabric conditioner to produce the desired pH.

If the reuse is as wash water to which fabric conditioner is to be added, the concentration of sulfate ions in the wash water is preferably not too high to avoid precipitation of the fabric conditioner. For example, using a low concentration of aluminum sulfate as the main flocculant can avoid this phenomenon. Therefore, the main flocculant preferably uses polyvalent cations without sulfate ions, such as aluminum chloride or a mixture of aluminum sulfate and chloride, for example, including 5-60% by weight, preferably 15-35%, more preferably 20% - 30% aluminum sulfate, and 40-95% by weight, preferably 65-85%, more preferably 70-80% aluminum chloride. The use of such mixtures has been found to be preferred over the use of sulfates alone since the use of sulfates alone results in reduced performance of fabric softeners dissolved in water. In addition, sulfate ions can also be removed, such as with ion exchange resins, prior to the addition of fabric conditioners.

An additional benefit of the present invention is that useful components can be brought to the purified water for reuse. For example, the concentration of surfactant can be reduced by a factor of about 5-20, usually about 10 times, and the fraction of surfactant carried over to the reuse water favors the reuse of water for the washing step. Also, fragrances and/or dyes from the detergent may be carried over to the purified water. This water is desirably reused as a rinse step water and has an attractive color and/or aroma. Therefore, another good improvement of the present invention is that the water purification method is used in combination with a detergent comprising a fragrance that is more fragrant than 3,7 dimethyl-2,6,octadiene-1-carbonitrile ( Geranyl nitrile) is stronger. This evaluation was carried out by a five-person fragrance expert panel, comparing the fragrance of a 20% by weight fragrance solution in diethyl phthalate with a 20% by weight solution of geranylnitrile. This comparison should be made using a sniff strip. The fragrance produced by using such a fragrance can be carried into purified water and reused in steps such as washing clothes.

In another preferred embodiment, fragrances and/or dyes may be added with the flocculant to create an attractive fragrance and/or color suitable for use as wash water. If the purified water is to be reused in the washing step, it is desirable that the pH of the water be greater than 7. In addition, flocculants can be selected to automatically generate water with a pH greater than 7, or pH regulators can be added before the purified water is reused. Any base may be added to obtain the desired basic pH.

In particular, it has been found that high electrolyte concentrations in the water that are reused in the washing step adversely affect the efficacy of the washing liquor due to the addition of flocculant polyvalent metal salts to the water reused in the washing step. The above problems can be solved by using ion exchange filters, or preferably by adding metal ion chelating agents to the purified water before adding detergent, optionally using pH adjusters to make the pH of the water neutral to alkaline so that the detergent With the best performance.

Suitable chelating agents include the water-soluble and/or insoluble builders described below, but are preferably heavy metal ion sequestrants, preferably water-soluble builders and heavy metal sequestrants, especially the latter. Since these substances are effective even at extremely low concentrations, it is useful to add an amount of these substances to purified water to produce a concentration of at least several ppm. For example, 0.005 g/l to 10 g/l may be added.

Heavy Metal Ion Sequestrants

Heavy metal ion sequestrants are preferred chelating agents of the invention. A heavy metal ion sequestrant here refers to an ingredient that sequesters heavy metal ions. These ingredients can also have calcium and magnesium chelating properties, but preferably they have the ability to chelate heavy metal ions such as iron, manganese and copper, or any other metal ions added as flocculants.

Heavy metal ion sequestrants suitable herein include organic phosphonates such as amine alkylene poly(alkylene phosphonates), alkali metal ethane 1-hydroxy diphosphonates and nitrilo trimethylene phosphine salt. Examples include diethylene triamine penta (methylene phosphonate), ethylene diamine tri (methylene phosphonate), hexamethylene diamine tetra (methylene phosphonate) and hydroxyethylene 1,1 diphosphonate, 1,1 hydroxyethane diphosphonic acid and 1,1 hydroxyethane dimethylene phosphonic acid.

Preferred heavy metal ion sequestrants for use herein include nitrilotriacetic acid and polyaminocarboxylic acids such as ethylenediaminetetraacetic acid, ethylenediaminesuccinic acid, ethylenediamineglutaric acid, 2-hydroxypropanediaminebutyl diacids or their salts.

Other heavy metal ion sequestrants suitable herein include derivatives of iminodiacetic acid described in EP-A-317,542 and EP-A-399,133, such as 2-hydroxyethyldiacetic acid or glyceryliminodiacetic acid. The iminodiacetic acid-N-2-hydroxypropylsulfonic acid and aspartic acid N-carboxymethyl N-2-hydroxypropyl-3-sulfonic acid sequestrants described in EP-A-516,102 are also suitable in the present invention. β-alanine-N,N'-diacetic acid, aspartic acid-N,N'-diacetic acid, aspartic acid-N-monoacetic acid and iminosuccinic acid described in EP-A-509,382 Sequestrants are also suitable for use in the present invention. EP-A-476,257 describes suitable amino sequestrants. EP-A-510,331 describes sequestrants derived from collagen, keratin or casein. EP-A-528,859 describes suitable alkyliminodiacetic acid sequestrants. Also suitable are dipicolinic acid and 2-phosphonobutane-1,2,4-tricarboxylic acid. Also suitable here are glycinamide-N-, N'-succinic acid (GADS), ethylenediamine-N-N'-glutaric acid (EDDG) and 2-hydroxypropylenediamine-N-N'- Succinic acid (HPDDS).

Especially preferred are diethylenetriaminepentaacetic acid, ethylenediamine-N-N'-succinic acid (EDDS) and 1,1 hydroxyethanediphosphonic acid or their alkali metal, alkaline earth metal, ammonia or substituted ammonium salts , or a mixture thereof.

water purification composition

The present invention includes a water purification kit suitable for household use for purifying and reusing water, the kit including at least one unit dose of flocculant, one unit dose comprising 0.03-250 g of flocculant, preferably 0.05 to 100 g of flocculant. As mentioned above, the flocculant preferably includes a primary flocculant and a secondary flocculant, so a preferred reagent package includes the primary flocculant and secondary flocculants used in the above method, and the flocculants are preferably separated and can be added simultaneously or sequentially. In the particularly preferred reagent pack of the present invention, the flocculant is divided into two separate unit doses, including a first unit dose and a second unit dose, and the first unit dose includes 10-200g of the main flocculant polyvalent metal ion, or 0.03-5g containing The flocculant for PEI, the second unit dose includes 0.01-20 g of the secondary flocculant, preferably 0.01 to 10 g, more preferably 0.01 to 5 g.

The unit dose may also contain other substances such as binders, fillers, processing aids, solvents and/or disintegrants. The unit dose may also include a bubbling system as described above, which can generate gas to accelerate the floating of the formed flocs, and also serve as a disintegrating agent for the unit dosage form to ensure the rapid release of the flocculant into the wastewater. Other suitable disintegrants are the substances commonly used in pharmaceutical and tablet technology, such as those described in EP711828A, EP488484A and EP522766A.

The water purifier pack may also contain unit doses of pH adjusters and/or chelating agents as described above, in which case it is desired to reuse the purified water in the laundry washing step.

The present invention also includes a water purification kit comprising a water purification composition, and additionally means for removing formed flocs, such as one or more filters or for collecting and removing flocs from treated wastewater High specific surface area devices for objects.

Separation of flocs

The flocs formed in the process of the present invention can be separated from the waste water by any conventional method. For example, where floc is floating, it can be removed by skimming or removing it from the wastewater surface using implements such as ladles or spoons. Additionally, where the flocs settle or float, clean water is siphoned or poured/decanted from above or below the flocs until the clear water begins to entrain the flocs. Wastewater containing flocs can be disposed of as waste. In addition, floc is removed by agitation in wastewater containing floc with a high surface area device, such as a brush that traps the floc and can then be removed. Brushes can be designed to be electrically charged or have other surface properties, such as stickiness, so that the surface attracts floe. The brush is then dried, and the flocs are easily removed after drying. In addition, by filtering to remove flocs, the water containing flocs can be passed through a filter located at the outlet end of the treatment vessel, or a sealable and removable cover or frame made of filters can be provided above the washing vessel, Water is thereby poured from the washing vessel through the filter, or the filter is a "hood" placed at the water inlet end of the vessel through which clean water is poured into the vessel for storage or immediate reuse. It is even possible to pull the filter through the water containing the flocculant, thus capturing the flocs that form. Suitable filters include filters composed of any suitable mesh. The sieve hole should not be too small so as not to make the filtration speed too slow and cause flocs to block the filter. Likewise, the mesh of the filter should not be too large to allow a large amount of floc to flow through the mesh. Suitable materials include paper, fabric, metal, polymeric materials containing foam (polyurethane foam of standard cell size has been found to be particularly useful), or minerals such as porous stone. Preferably the filter is at least partially flexible so that the filter can be easily installed into a washing machine or other disposal container.

Filters can be reused and cleaned between filtrations, for example, can be removed relatively easily from reused filters (such as metal or plastic filters or fabric filters) by cleaning after drying, or by scraping, or other physical removal methods. or brush,) to remove floc. In addition, the filter may be disposable such that a new filter is used after one or more filtrations.

In another aspect of the present invention there is provided a washing vessel for carrying out a domestic washing process in which waste water from the washing and/or cleaning steps of the washing process is purified by removal of particulate solids, the washing vessel comprising an inner layer and an outer layer, The first layer forms the coherent surface in which the water used for washing is located during the washing process, and the second layer is the screen through which the water flows while filtering particulate solids.

Where the wash container includes a disposable filter, the filter should be easily removable for replacement, for example by having a roll of filter material at the bottom of the wash container or in a separate filter container that can be pulled apart to spill out when the filter material needs to be changed during filtration A piece of new filter material.

Attached picture

A preferred embodiment of the invention is shown in Figure 1, which shows a cross-sectional view of a container. In this embodiment of the invention, the inner layer has a screen. The inner layer 1 is close to the inside of the outer layer 2, and a filter screen 3 is arranged in the inner layer.

FIG. 2 is an enlarged cross-sectional view of A-A in FIG. 1 . It can be seen that the filter screen 3 is arranged in the inner layer 1. According to a preferred aspect of the present invention, a movable sealing body 4 is provided for use in the washing process so that the washing or cleaning water does not contact the filter screen 3. At the end of the washing process, the movable seal 4 is removed by pulling the release part 5 apart. The movable sealing body is made of elastic material which is easily deformable or bendable and can be installed against the filter screen. During the filtering step of the water flow filter screen, the screen screen is exposed so that solid particles are trapped on the screen screen.

Fig. 3 is a sectional view of another embodiment, at A-A, the filter screen 3 is arranged in the inner layer 1, the movable sealing body 4 is arranged on the filter screen, and the sealing body 4 can be moved by using the loosening part 5. The preferred embodiment shown in Fig. 2 is because those skilled in the art can easily see that the loosening part 5 is matched with the protruding rafter 6 extending upwards, which can prevent water from contacting the filter screen under the protruding rafter 6, thereby avoiding incomplete filter. However, the remaining water can be discarded with the particulate solids, so such an embodiment would still work well.

In the embodiment shown in Figures 1 to 3, at the end of the washing process, the movable sealing body 4 is moved, exposing the filter sieve through which waste water leaks, lifting the inner layer 1 from the outer layer 2 and holding it so that the water flows through the filter 3 and enter container 2 while the particulate solids are trapped on screen 3. The purified water from which particulate solids have been removed is then reused in the outer layer 2 .

Another embodiment of the present invention is shown in FIG. 5 . In this embodiment, the outer layer is provided with a strainer 3 and the inner layer 9 has holes with a cover 8 which allows the inner layer to form a continuous surface so that the wash water is contained in the wash container during the washing process but removed. When the lid opens the holes, purified water can flow through the filter screen 3 thereby trapping particulate solids on the filter screen 3 .

As can be seen from the above examples, the screen does not necessarily extend over the entire inner or outer surface, but such an embodiment is within the scope of the invention.

The outlet hole 8 may be provided by any movable seal such as a plug, or a tight lid, or a segmented partition that can be opened and closed.

Typically, the screen extends only to a portion of the inner or outer surface. However, it can be seen in FIG. 6 that the screen itself forms the entire outer surface.

Screens are typically made of a polymeric material such as polyethylene or polypropylene, but can be made of any suitable material that retains particulate solids while allowing water to flow through. The pores of the strainer should be small enough to capture solids without impeding water flow, but not so large that the filtered particulate solids flow through the strainer. Usually, the filter mesh is 10-300 microns, preferably 100-250 microns. Other materials from which the screen is made are metal or any other material. If the filter screen itself is made of elastic material, it can be strengthened by mixing mesh fabric into the solid carrier, such as shown in Figure 4, the rim 11 and the spokes 12 are made of any strong material, such as polymeric material 13 can be made of nylon or any other elastic mesh material or the like.

It can be seen that embodiments of the water container of the present invention are in all respects suitable for use in the water purification method of the present invention whereby solids are flocculated by adding a flocculant system and optionally other additives to wastewater.

Example

example 1

The soiled clothes were washed in 30 liters of water with a standard dosage of a commercially available phosphate based laundry detergent composition at a concentration of 2500 ppm detergent in the wash water.

After completion of the washing process, the detergent suds had disappeared and the soil concentration in the water was 4 g/l, measured by drying the sample in a drying oven at 120°C. 70 g of a mixture of Al ₂ (SO ₄ ) ₃ .16H ₂ O and AlCl ₃ .6H ₂ O in a weight ratio of 30:70 was added to 30 liters of waste water. After gently stirring for 10 seconds, 30 ml of a 1 wt % Polymin KP97 (trade name of BASF) solution was added, while stirring gently for 90 seconds. Formation of large flocs. The waste water containing flocs is then discharged from the water container through polyurethane foam discs, which capture the flocs and allow clear water to quickly pass through the foam, thereby being collected for reuse. The resulting purified water has a pH of approximately 4 and is clear in appearance, suitable for reuse as a cleaning solution. This water was reused in the garment wash step where a commercially available fabric softener was added at the manufacturer's recommended dosage.

Example 2

A commercially available phosphate-based detergent composition was dissolved in 5 liters of water, and the detergent concentration in the wash water was 5600 ppm. The common soil mixture that can be found on soiled clothes is added to the water at a concentration equivalent to 2500ppm to create a wastewater solution.

In this 5 liters of waste water, add flocculant system, this flocculant system comprises the aluminum chloride hexahydrate of 22.5g, the aluminum sulfate hexadecahydrate of 7.5g (the weight ratio of aluminum chloride and aluminum sulfate is 3: 1), and 0.375 g of Magnafloc ^™ 155. A further 11.5 g of sodium carbonate were added. All these additives are added simultaneously in granular form. A floc formed after vigorous stirring. Effervescence was observed and the resulting flocs collected on the surface of the water. Wastewater before adding flocculant system looks cloudy. The waste water containing flocs is then passed through a 150 micron filter, which captures the flocs and allows clear water to pass through the filter quickly and be collected for reuse. The resulting purified water has a pH of about 6 and is clear in appearance, suitable for reuse in the wash step of the domestic laundering process.

Example 3

In 5 liters of water, dissolve a standard dose of a phosphate-based detergent composition containing approximately the following ingredients:

Sodium alkylbenzene sulfonate 20wt%

Sodium tripolyphosphate 30wt%

Sodium Carbonate 15wt%

Sodium Sulfate 15wt%

Sodium silicate 10wt%

Sodium perborate (monohydrate or tetrahydrate) 2.5wt%

Foam inhibitor 1wt%

Magnafloc 1.6wt%

Spices, water and others make up to 100wt%

The detergent concentration in the wash water was 2500 ppm. A typical scale of 2.5 g/l or 2500 ppm is dispersed into the wash water to produce waste water. To 5 liters of waste water, add the main flocculant, the main flocculant includes 11.25g of aluminum chloride hexahydrate and 3.75g of aluminum sulfate hexadecahydrate (the weight ratio of aluminum chloride to aluminum sulfate is 3:1). Also add 5.5 g of sodium carbonate. All these additives are added simultaneously in granular form. A floc formed after vigorous stirring. Effervescence was observed and the resulting flocs collected on the surface of the water. Use a siphon to draw clear water from under the flocs or filter through a filter to separate the clear water from the flocs, and collect the clear water for reuse. In addition, the solution is drained using polyurethane foam discs, which capture flocs and allow clear water to pass through the foam quickly, thereby collecting clear water for reuse. In this example, filter through a 150 micron filter to separate the flocs from the clear water. The resulting purified water has a clear appearance and is suitable for reuse in the washing step or cleaning step of a domestic washing process.

Claims (20)

1. A method of treating waste water from a domestic washing process, comprising separating laundry items from waste water containing organic and/or inorganic dirt and synthetic detergents from the washing and/or cleaning steps, and bringing the waste water into contact with a flocculant system to form flocs A flocculant system comprising a primary flocculant selected from polyvalent cations and polyethyleneimines or mixtures thereof and a secondary flocculant selected from anionic and nonionic polyelectrolytes and mixtures thereof to separate flocs from wastewater out, produce purified water, and reuse the purified water, wherein an alkali source pH regulator is also added to the wastewater, and at least the main flocculant is added to the wastewater before adding the alkali source. 2. A method of treating waste water from a domestic laundering process, comprising separating laundry items from waste water containing organic and/or inorganic soils and synthetic detergents from the washing and/or cleaning steps, contacting the waste water with a flocculant system, said flocculant The system contains a primary flocculant selected from polyvalent cations and polyvinylamines or mixtures thereof and a secondary flocculant selected from cationic polyelectrolytes and mixtures thereof, and reuses the purified water, wherein an alkaline source pH regulator is also added to the wastewater , and at least the main flocculant is added to the wastewater before adding the alkali source. 3. A method as claimed in claim 1 or 2, wherein the pH adjusting agent is carbonate or any other buffer salt. 4. The method as claimed in claim 1 or 2, wherein the primary flocculant and the secondary flocculant and the alkali source are metered into the waste water at the same time, and the alkali source is in a slower dissolving form than the primary flocculant. 5. A method as claimed in any one of the preceding claims, wherein an acid source pH regulator is added to the waste water in addition to the flocculant system. 6. A method as claimed in claim 5, wherein the acid source is added to the waste water simultaneously with or prior to the primary flocculant. 7. The method as claimed in claim 6, wherein in the first contacting step, the waste water is contacted with the primary flocculant and agitated so that the flocs start to form, and in the second contacting step, the waste water is contacted with the secondary flocculant. 8. A method as claimed in any preceding claim, wherein the domestic laundering process is a laundry process. 9. A method as claimed in any preceding claim, wherein the flocculant system is a system capable of producing floating flocs. 10. A method as claimed in any preceding claim which includes providing a bubbling system for generating/releasing gas in the wastewater. 11. A method as claimed in any one of the preceding claims, wherein the primary and secondary flocculants are sequentially contacted with the wastewater. 12. A method as claimed in any preceding claim, wherein the purified water is reused in another laundry process step, either washing or rinsing. 13. A method as claimed in any one of the preceding claims, wherein prior to reuse, a chelating agent is added to the purified water to sequester metal ions from the flocculant. 14. A method as claimed in any one of claims 1 to 13, wherein the floc is separated from the waste water by lifting a filter or screen from the water containing the floc. 15. A water purification composition for domestic use comprising a flocculant comprising a primary flocculant selected from polyvalent metal cations and/or polyethyleneimines and comprising anionic, nonionic or cationic polyelectrolytes or The secondary flocculant of its mixture. 16. A water purification kit for household use comprising at least one unit dose of flocculant, or means for providing at least one unit dose of flocculant, said one unit dose comprising 0.03-250 g of flocculant, said flocculant comprising A primary flocculant selected from polyvalent metal ions and polyethyleneimine or mixtures thereof and a secondary flocculant selected from anionic, nonionic or cationic polyelectrolytes or mixtures thereof. 17. The water purification kit of claim 16, comprising a first unit dose comprising said primary flocculant, and comprising a second unit dose comprising said secondary flocculant . 18. A water purification kit as claimed in claim 16 or 17, comprising a primary flocculant and a secondary flocculant comprising an anionic and/or nonionic flocculant, and also a source of alkalinity. 19. A water purification kit as claimed in any one of claims 16 to 18 wherein the primary flocculant and source of alkalinity are in such a form that they dissolve in treated wastewater at a slower rate than the primary flocculant. 20. A water purification kit as claimed in any one of claims 16 to 19 wherein the primary and secondary flocculants and source of alkalinity are in particulate form but the source of alkalinity is provided in a form which dissolves at a slower overall rate than the primary flocculant.