NO329274B1 - Conditioning agent for stagnant and liquid water systems and methods for preventing deposits in these water systems. - Google Patents

Abstract

A conditioner (especially a tablet or deposited product) for still or flowing water contains (a) a polysuccinimide or partial hydrolysate; and (b) a biostat.

Description

The present invention relates to water conditioners based on a mixture of polysuccinimide (PSI) with at least one biostatic agent as well as a method for preventing deposits that occur in systems of stagnant or liquid water due to hardness-forming ions, using the water conditioner according to the invention.

Liquid water systems in connection with the present invention are considered dewatering systems or drainages of construction works, but also pressurized water during the extraction of raw materials, especially of crude oil or natural gases, particularly preferred in the so-called "Squeeze" operations within crude oil extraction (known from US-A 5 655 601) .

Construction works where the conditioning agent according to the invention can be used are, for example, buildings, tunnel constructions, tunnels, caverns, dam walls, dams, hydroelectric power plants, earthen dams, retaining walls, road construction, falls of irrigation systems, water drainage channels, spring enclosures or temporary construction pits. Construction works in connection with the present invention are also infrastructure facilities such as landfills (for municipal or industrial waste) including drainage systems that penetrate these, as well as bridges and their drainage systems or treatment plants.

Standing water systems in connection with the present invention are, for example, standing water in swimming pools or also as a matrix in underground crude oil deposits and swimming pools.

The mentioned construction works, respectively the operations, during the utilization of the water properties of the relevant groundwater, waste water, drainage water or liquid water show a different high content of dissolved water constituents. These predominantly organic water constituents often cause hard deposits. When, for example, groundwater or drainage water enters drainage systems, the physical properties change so that the originally dissolved water-containing substances form hard, adherent deposits, which can be in amorphous or crystalline form. These deposits (sinterings) usually consist of calcium carbonate, magnesium carbonate, calcium sulfate (gypsum), silicates (SiO2), barium sulfate and iron oxides, all possibly in their hydrated form, or calcium magnesium phosphate or other phosphate-containing double salts, which are for example described in DE-A 10 207 088.

These hard, clinging deposits reduce the flow cross-section of drains or in extreme cases completely block the drain/pipelines. As a result of this, the formed amounts of water cannot flow away freely and accumulations form which can cause major damage.

Within the area of, for example, swimming pools, the contained water must be conditioned in such a way that there are no deposits on the cell walls or in pump filters. Within the area of extraction of raw materials, for example crude oil extraction, the conditioners used there require high pressure stability and high thermal stability.

From DE-A 10 101 671, conditioners are known which, in addition to PSI, can also contain fatty acids and biocides.

For example, phthalimidoperoxohexanoic acid, dibenzoperoxide, chlorobromodimethylhydantoin or further organic peroxides are proposed as biocides. These are biocides which release oxygen or chlorine and which must be classified as water-labile as this release takes place very quickly. Furthermore, they are not unconditionally applicable in all aqueous media, especially not when the water to be conditioned is to be used within the food industry or after purification in treatment plants is to be released into natural water reservoirs or into surface water.

Furthermore, when using tablets according to DE-A 10 101 671, it was observed that in germ-carrying water systems, after a certain time, despite the addition of biocides, after their breakdown or decomposition, an attack on the tablets by microorganisms, primarily yeast and /or molds, which led to such a thick fouling of the release of PSI to dissolve the adhering deposits of the type mentioned above, were no longer sufficiently secured.

Consequently, the task was to develop an improved water conditioner based on PSI which, in the long term, prevents growth on PSI tablets.

This task was solved by using PSI together with biostatics which, as water-stable preservatives, not only ensure a more favorable toxicological profile, but also a longer-lasting effect of PSI.

The subject of the present invention is water conditioners, in particular storage stones or tablets, for conditioning stagnant and flowing water systems, which are characterized by the fact that they contain an effective content of polysuccinimide (PSI) or its partial hydrolyzate as well as a biostatic agent, whereby the content of PSI lies between 0, 1 to 10,000 g/m<3> and of the biostatic agent 0.1 to 100 g/m<3> of the water to be conditioned and that phenols are used as biostatic agents, preferably phenol itself, or phenylphenol and sodium orthophenylphenolate.

The object of the present invention is also a method for preventing deposits in stagnant or flowing water systems, which is characterized by the fact that a conditioning agent is added to the stagnant water or drainage water, waste water, flow water or ground water that is carried away.

By adding a conditioning agent based on PSI, together with a biostatic agent, to the water to be treated, not only can the growth of unwanted crystal germs be effectively prevented, but at the same time the inhibition of PSI by yeasts or molds is avoided over a longer period of time than can be achieved with biocides. At the same time, the formation of new pore deposits becomes impossible.

Conditioners for aqueous systems are designated differently due to their mode of action, for example as dispersants, hardness stabilizers and protective colloids. Sequestering agents (complexing agents) or possibly also additional surface-active substances (surfactants) and optionally also biocides can also be added to them. Also important are hardness stabilizers, i.e. compounds which are suitable for stabilizing the hardness formers in dewatering systems, whereby they deactivate crystal growth and mostly exhibit surface charge-changing properties, as well as dispersants (dispersants). Dispersants are compounds that change surface charge, which disperse undissolved solid particles in water - also in the colloidal region - i.e. keep them finely distributed. Conditioners according to the invention on comprehensive PSI and biostatics are added to stagnant or flowing water systems depending on the applicable area of application.

Consequently, extraction processes for crude oil or natural gas, especially the "squeeze" operations, clearly require higher PSI amounts than the application in stagnant water systems, such as for example swimming pools. PSI and biostatics are therefore added to the stagnant or flowing water system, preferably in aqueous solution, in amounts from 0.1 to 10,000 g/m<3> PSI and 0.1 to 100 g/m<3> biostatics, especially 0.5 to 5000 g/m<3> PSI and 0.5 to 50 g/m<3> biostatic for the water to be conditioned.

Hardness stabilizers and dispersants often intersect in terms of effectiveness. Consequently, the conditioning agents according to the invention can also be used in combination with hardness stabilizers or dispersants, whereby a higher degree of effectiveness is usually achieved compared to the separate use. The conditioning agents according to the invention can also contain other suitable additives, whereby the future utilization of the diverted drainage or ground water is always decisive, in order to achieve an environmentally friendly prevention of sintering.

PSI or its partial hydrolyzate, which is used in the conditioning agents according to the invention, shows a very favorable effect correlation of dispersing and hardness stabilizer properties and, due to the slow release effect, i.e. the gradual release of the active ingredient polyaspartic acid, can be used for conditioning stagnant and flowing water systems, especially building drainage, tunnel drainage and within crude oil extraction. PSI as well as its partial hydrolysates are therefore particularly suitable for preventing deposits, especially of calcium carbonate, magnesium carbonate, calcium sulfate, silicates, barium sulfate, iron oxides or phosphate-containing double salts such as calcium magnesium phosphate. In addition, PSI in the conditioning agents according to the invention shows the following advantages: • PSI is not hygroscopic and can be pressed into form-stable storage stones with a low binder content of, for example, < 10%. • As an imide, PSI shows a relatively higher percentage of active ingredient by weight than the sodium-containing sodium polyaspartate. • PSI dissolves slowly, whereby the rate of dissolution increases with pH; hence it exhibits the desired slow release property. • Due to its low solubility, PSI shows a reduced degradation rate compared to polyaspartic acid with a correspondingly reduced potential for biopollution. • Due to its acid-releasing property, PSI is able to regenerate and dissolve lime deposits. In contrast to the easily soluble organic acids, the insoluble PSI ensures that the active ingredient precursor remains in place with pre-sintering. Moreover, PSI partial hydrolysates can because of their

adsorption capacity of calcitic acid locally binds to lime surfaces and thus dissolves lime with a very high dosage effect ratio.

PSI can be produced on a large technical scale by thermal polymerization of maleic anhydride and ammonia or their derivatives (see US-A 3,846,380; US-A 4,839,461; US-A 5,219,952 or US-A 5,371,180).

PSI is also obtained by thermal polymerization of aspartic acid (US-A 5,051,401) possibly in the presence of acidic catalysts/solvents (US-A 3,052,655).

PSI is formed by the chemical synthesis as a polymer with an average molecular weight of 500 to 20,000, preferably 3,000 to 5,000. Polysuccinimide is considered the chemical precursor of polyaspartic acid, to which it is slowly hydrolysed with water. The pH value of the resulting solution lies between pH 1 to 4, preferably at 2 to 3. In this way, not only the good stone dissolving, but also at the same time the dispersing effect of the polyaspartic acid released by PSI applies to poorly soluble calcium salts, respectively other sparingly soluble substances. The resulting acidic solution also leads, due to the acid action, to the direct dissolution of any formed calcium carbonate incrustations. Above all in hard mountain waters with an elevated pH value and thus increased incrustation problems, PSI favorably shows an increased solubility. In addition, due to the slow hydrolysis at the same time low water solubility, PSI is long-acting at the point of application and thus clearly superior to the direct application of polyaspartic acid (slow release effect).

Optionally, in addition to PSI in the conditioners according to the invention, additional hardness stabilizers can be used. As additional hardness stabilizers, compounds from the group of inorganic condensed phosphates can be used, such as alkali di-, tri- and -polyphosphate, organic phosphorus compounds or organophosphonic acids, such as, for example, 2-methyl-propane-phosphonic acid, hydroxyethylidene diphosphonic acid, aminomethylenephosphonic acids, N-containing phosphonates, aminophosphonates, aminoalkylenephosphonic acids such as aminotri(methylenephosphonic acid) or diethylenetriamino-penta(methylenephosphonic acid), poly(aminomethylene-phosphonates) or hydroxyethyl-ethylene(di(aminomethylene)-phosphonic acid), further phosphonocarboxylic acids, for example phosphonobutane-tricarboxylic acids, phosphate esters, polyphosphoesters, aminophosphates, succinic acid amide, carbohydrates, polysaccharides, gluconates, polyglycosides, polyglucosides and their derivatives, polyoxycarboxylic acids and their copolymers, oxidized carbohydrates, such as oxidized celluloses, starches or dextrin, proteins and other egg white products, water-soluble polyamino acids, for example polyaspartic acid, silicates, such as alkali silicates, water glasses or zeolites.

The water-soluble salts of the indicated acids are also suitable as hardness stabilizers in addition to PSI, preferably the sodium salts.

In a particularly preferred embodiment of the present invention, PSI is present together with polyaspartic acid in conditioners. As PSI hydrolyses to polyaspartate under suitable conditions, but in itself, however, is to be considered hydrophobic, an effect on the curing stabilizer is achieved in the formulation according to the invention in a "slow release" formulation.

Optionally, the conditioning agents according to the invention can be added to dispersants. Suitable dispersants are, for example, tannin derivatives, such as sulfited tannins, lignin sulfonates, sulfonated condensation products of naphthalene with formaldehyde, polyacrylates, polymethacrylates, polyacrylamides, acrylate-based polymers, further P-containing polymeric compounds, such as N-phosphonomethyl-macrocyclic polyethers or phosphonomethylated oxyalkyleneamines as well as phosphinic acid-containing homo- and copolymers of acrylic acid and acrylamide and oligomeric phosphinicosuccinic acid compounds (as described in US-A 4,088,678). Also suitable are polymers with N-substituted amide functions, for example sulfomethylated or sulfoethylated polyacrylamides and polymethacrylamides and copolymers respectively terpolymers with acrylic acid and maleic acid ester, N-butylacrylamide and its copolymers, 2-acrylamido-2-methyl-1-propanesulfonic acid as a salt and their alkyl-substituted alkyl derivatives and their copolymers, further phosphinoalkylated acrylamide polymers and copolymers with acrylic acid, copolymers with alkenes with unsaturated dicarboxylic acids and polymers and copolymers based on maleic acid. Such and similar compounds are described, for example, in EP-A 225 596, EP-A 238 852, EP-A 238 853, EP-A 238 729, EP-A 265 846, EP-A 310 099, EP-A 314 083 , EP-A 330 876 or EP-A 517 470. Water-soluble salts of corresponding acids are likewise suitable.

Optionally, the conditioners according to the invention may contain sequestering agents.

Examples of suitable sequestering agents or complexing agents in connection with the present invention include iminodisuccinate (IDS), nitrilotriacetic acid, citric acid, ethylenediaminetetraacetic acid (EDTA), ether carboxylates and oxidized carbohydrates, for example partially hydrolyzed and oxidized starches and dextrins. Phosphorus-containing complex formers such as condensed phosphates and phosphonates are also suitable, provided that these are not already used in their function as hardness stabilizers.

Optionally, the conditioning agents according to the invention contain further additives such as aluminate compounds (see EP-A 0 302 522), stabilizers such as polyquaternary amines, for example poly(dimethylamino-co-epichlorohydrin) or poly(diallyldimethyl-ammonium chloride) (see US-A 5 038 861 ) or suitable surfactants, such as, for example, alkyl-aryl-sulphonates, polyvinylsulphonates, sodium methoxymethylcellulose, etc.

The use of biostatics does not exclude the simultaneous use of biocides. When they are suitable for the use of the conditioning agents according to the invention, biocides can be added. In principle, all biocides which according to national regulations can be used to keep water clean are suitable for this purpose. As preferred biocides in connection with the present invention, phthalimidoperoxohexanoic acid, dibenzoperoxide, chlorobromodimethylhydantoin or further organic peroxides are used.

The use of the conditioning agent according to the invention can take place in the usual form, such as powder, tablets or depot stones. Moreover, further forms of application are also possible, which support the depot effect (i.e. the gradual and temporally constant release of the active substance of PSI or the slow release property, as well as the release of the biostatic agent). Particularly suitable for this purpose are water-permeable or self-dissolving bags made of suitable synthetic or biodegradable polyester amides, such as BAK™ (Bayer AG), whereby during the biological breakdown of the matrix (polyester amide) PSI is converted to polyaspartic acid.

The compression of PSI with the relevant biostatic agent in so-called depot stones or tablets takes place possibly with the help of various excipients. Particularly suitable as auxiliary substances in connection with the present invention are fatty acids, especially stearic acid, palmitic acid or lauric acid.

For example, depot stones are mentioned in the Swiss building magazine from SIA "Schweizer Ingenieur und Architekt", Nr. 12, 24 March 2000.

Examples

Formulation examples

Example 1

90% PSI was thoroughly mixed with 1.5% biostatic and 8.5% palmitic or stearic acid, and this mixture was, by means of a tableting machine, compressed to

tablet-like shaped bodies. These shaped bodies were used at a dissolution rate of 70 mg/hour, weight 50 g, in such quantities that the concentration in the drainage water from approx. 0.1 to 100 ppm and a concentration of 0.1 to 100 ppm biostatic was ensured.

Example 2

A further example for neutral water contained 70% PSI, 25% polyaspartic acid sodium salt and 4.5% palmitic respectively stearic acid and 0.5% o-phenylphenol respectively natnum-o-phenyl-phenolate (Preventol ® ONS) hereinafter designated as ONS.

A tablet according to example 1 showed, after 2 months of placement in a building drainage system, a germ count density 3 orders of magnitude lower than a tablet without biostatic agent (90% PSI, 10% stearic acid).

Application examples

Antimycotic effect of PSI-containing tablet-like shaped bodies.

1. Material and methods

1. 1 Agar types used:

Code no. 211 Sabouraud-Agar 2% glucose (Merck/l .07315)

Code no. 214 Sabouraud-Agar with 4% glucose (Merck/1.05438) and 0.005%

chloramphenicol (Sigma)

Code no. 267 Antibiotics-Agar no. 19 (Difco/0043-17-0)

1. 2 Preparation of test plates:

After corresponding pre-tests with all three agar varieties, the best results are obtained with agar 211 and 267, which are consequently used in the following for the qualitative bioanalyses (inhibition zone test, respectively agar diffusion test).

The liquid agar is added to a volume of 700 ml in each case 10 ml of a working suspension of the test germs Candida albicans (yeast) or Aspergillus niger (mould) with a germ titer of approx. 10<7> CFU/ml.

1. 3 Execution of the experiment (inhibition area test)

Equally large pieces of PSI-containing tablets (PSI with 0.7% ONS and PSI with 1.5% sorbic acid respectively) were placed on the fixed agar plates and incubated at 28°C for 5 days in an incubation cabinet.

An antifungal active formulation (Clotrimazole) was used as positive controls. The plates were assessed on all working days and the inhibited areas were visually assessed.

1. 4 Test in liquid culture:

Equal-sized pieces of PSI-containing tablets (PSI with 0.7% ONS and PSI with 1.5% sorbic acid, respectively) were added to the flask with 50 ml of casein peptone-soya melpeptone broth (CSB for example oxoid/ICM 129) as liquid medium and mixed with 0.1 ml of a working suspension of the test germs Candida albicans (yeast) or Aspergillus niger (mold) with a germ titer of 10<7> KBE/ml.

The flasks were incubated with shaking and in parallel without shaking at 28°C, and the growth of the test germs was judged in the presence of PSI-containing Tabs on the basis of the turbidity of the nutrient medium compared to inoculated nutrient medium without PSI (positive control).

2. Results

2. 1 Test of the inhibition area

After one day, both tablets show a comparable inhibitory effect against yeast and moulds, whereby the tablets concentrated with sorbic acid form clearer and sharper inhibitory areas. An exact quantification of the inhibitory effect is not possible in this case. However, the diameter of the inhibition zone can in principle be correlated with concentration, whereby for a quantification, however, an accurate reference with different concentrations of a suitable standard substance is required. In this connection, it must also be noted that the size of the inhibition areas also depends on the molecular weight of the inhibitor in question, and especially on its diffusion behavior.

This means, for example, that low molecular weight substances that quickly diffuse in the agar form larger inhibition zones than high molecular weight substances with comparable antimicrobial activity.

When assessed after 4 days, none of the Tabs preserved with sorbic acid or ONS were overgrown with Aspergillus.

2. 2 liquid culture

For Candida albicans, the following bacterial counts were determined in the flasks after incubation:

The results for both microbicidal additives (1.5% sorbic acid and 0.7% ONS) are comparable. A germ reduction of around 1 log step is achieved compared to controls.

Claims (12)

1. Conditioning agent, especially depot stones or tablets, for conditioning stagnant and flowing water systems, characterized in that these contain an effective content of polysuccinimide (PSI) or its partial hydrolyzate as well as a biostatic agent, whereby the content of PSI is between 0.1 and 10,000 g/m <3> and of the biostatic agent 0.1 to 100 g/m<3> of the water to be conditioned and that phenols are used as biostatic agents, preferably phenol itself, or phenylphenol and sodium orthophenylphenolate. 2. Conditioning agent according to claim 1, characterized in that hardness stabilizers from the group of inorganic condensed phosphates, organophosphonic acids, phosphate esters, polyphosphoric acid esters, aminophosphates, succinic acid amide, carbohydrates, polysaccharides, gluconates, polyglycosides, polyglucosides and their derivatives, polyoxycarboxylic acids and their copolymers are used in addition to PSI. polyglucosides and their derivatives, polyoxycarboxylic acids and their copolymers, oxidized carbohydrates, proteins, water-soluble polyamino acids, silicates or zeolites. 3. Conditioning agent according to one of claims 1 or 2, characterized in that dispersants from the group of tannin derivatives, lignin sulfonates, sulfonated condensation products of naphthalene with formaldehyde, polyacrylates, polymethacrylates, polyacrylamides, acrylate-based polymensates, P-containing polymeric compounds, phosphine-containing homo- and copolymers of acrylic acid and acrylamide, oligomeric phosphinicosuccinic acid compounds, sulfomethylated or sulfoethylated polyacrylamides and copolymers respectively terpolymers with acrylic acid and maleic acid ester, N-butylacrylamide and its copolymers, 2-acrylamido-2-methyl-1-propanesulfonic acid as salt and their alkyl-substituted derivatives and their copolymers, maleic acid or maleic anhydride polymers and copolymers, phosphinoalkylated acrylamide polymers and copolymers with acrylic acid, copolymers of alkenes with unsaturated dicarboxylic acids. 4. Conditioning agent according to one of claims 1 to 3, characterized in that complex formers from the group of iminosuccinate, nitrilotriacetic acid, citric acid, EDTA, ether carboxylates, oxidized carbohydrates or phosphorus-containing compounds are used. 5. Conditioning agent according to claim 1, character, in that it contains a biocide in addition to the biostatic agent. 6. Conditioning agent according to claims 1 to 5, characterized in that these are used in forms of application that increase the depot effect of PSI or its property of slow release. 7. Method for preventing deposits in stagnant or flowing water systems, characterized in that the stagnant water or drainage water, waste water, flow water or ground water that is carried away is added with a conditioning agent according to claim 1. 8. Method according to claim 7, characterized in that the liquid water system occurs within crude oil extraction or in tunnel drainage. 9. Method according to claim 7 or 8, characterized in that biocides are used as additives. 10. Method according to claims 7 to 9, characterized in that PSI, in order to increase its properties with slow release, are added aids. 11. Method for preventing deposits in swimming pools, characterized in that a conditioning agent according to claim 1 is added to the water to be conditioned. 12. Method according to claim 7, characterized in that the deposits consist of calcium carbonate, magnesium carbonate, calcium sulphate, silicates, barium sulphate, iron oxides or calcium magnesium phosphate.