Compositions with reduced salt concentration for production of biocides

Abstract

The invention discloses a composition for preparing a biocide. The composition comprises ammonium salt, ammonia water and sodium bicarbonate. The composition may be mixed with a hypochlorite oxidizing agent to form a biocide. Previously known compositions comprise only an ammonium salt and optionally a base. The composition of the present invention is more economically advantageous and has a more optimal pH compared to previously known compositions comprising monoammonium salts of strong acids (hydrobromic acid, hydrochloric acid or sulfuric acid) or comprising ammonium carbamate and sodium hydroxide. The preparation of the biocide may be monitored with a control parameter. A new control parameter, namely ORP / pH ratio, is introduced.

Description

[0001] Cross-reference to related applications:

[0002] Reference is made to U.S. Provisional Patent Application No. 63 / 398,558, filed on August 17, 2022, entitled METHOD FOR PRODUCING ABIOCIDE WITH LOW SALT CONTENT, the disclosure of which is incorporated herein by reference and priority is claimed hereunder under 37 CFR 1.78(a)(4) and (5)(i).

[0003] Reference is made to U.S. patent application Ser. No. 07 / 892,533, filed on Jun. 1, 1992, entitled PROCESS AND COMPOSITIONS FOR THE DISINFECTION OF WATERS, U.S. patent application Ser. No. 08 / 809,346, filed on Jan. 27, 1998, entitled METHOD AND APPARATUS FOR TREATING LIQUIDS TO INHIBIT GROWTH OF LIVING ORGANISMS, U.S. patent application Ser. No. 10 / 586,349, filed on Jul. 14, 2006, entitled BIOCIDES AND APPARATUS, U.S. patent application Ser. No. 14 / 765,335, filed on Aug. 1, 2015, entitled METHOD FOR CONTROLLING THE PRODUCTION OF A BIOCIDE, U.S. patent application Ser. No. 14 / 765,335, filed on Aug. 1, 2015, entitled METHOD FOR PRODUCING A BIOCIDE's U.S. patent application Ser. No. 17 / 621,014 and U.S. patent application Ser. No. 17 / 619,851, filed on Dec. 16, 2021, entitled PROCESS FOR PRODUCING ASOLUTION OF AMMONIUM CARBAMATE, the disclosures of which are incorporated herein by reference. Technical Field

[0004] The present invention relates to a composition for producing a biocide having a lower salt concentration relative to previously known biocide-forming compositions. Background Art

[0005] Various compositions and techniques are known for producing chloramines for use as biocides from ammonium salts. Summary of the invention

[0006] The present invention seeks to provide a composition useful for producing a biocide.

[0007] Therefore, according to a preferred embodiment of the present invention, a composition for preparing a biocide is provided, the composition comprising: an ammonium salt, including ammonium and an anion; ammonia water; and sodium bicarbonate; wherein a total molar amount of ammonia and ammonium in the composition exceeds an equivalent molar amount of the anion in the composition by at least 10%; wherein the equivalent molar amount of the anion is a molar amount of the anion multiplied by its valence.

[0008] According to a preferred embodiment of the present invention, the ammonium salt is selected from the group consisting of ammonium bicarbonate, ammonium bromide, ammonium carbamate, ammonium carbonate, ammonium chloride, ammonium phosphate, ammonium sulfamate and ammonium sulfate. Preferably, the ammonium salt is selected from the group consisting of ammonium bromide, ammonium carbamate, ammonium chloride and ammonium sulfate. Most preferably, the ammonium salt is ammonium bromide or ammonium carbamate.

[0009] According to another preferred embodiment of the present invention, the composition is an aqueous solution comprising the ammonium salt, wherein the ammonium salt is in a concentration range of about 4% by weight (w / w) to about 36% by weight (w / w), preferably in a concentration range of about 5% by weight (w / w) to about 27% by weight (w / w).

[0010] According to a different preferred embodiment of the present invention, the molar ratio of the ammonium salt to the ammonia water is in a range of about 1:10 to about 10:1, more preferably in a range of about 1:3 to about 3:1. Preferred embodiments of the present invention include wherein the molar ratio of the ammonium salt to the ammonia water is about 1:3, about 1:2, about 1:1, about 2:1 or about 3:1.

[0011] According to a preferred embodiment of the present invention, the concentration of the aqueous ammonia is in a range of about 1% by weight (w / w) to about 21% by weight (w / w), preferably in a range of about 2% by weight (w / w) to about 7% by weight (w / w). Preferably, the concentration of the sodium bicarbonate is in a range of about 0.2% by weight (w / v) to about 10% by weight (w / v), more preferably in a range of about 1% by weight (w / v) to about 5% by weight (w / v), and most preferably about 2.7% by weight (w / v).

[0012] According to a preferred embodiment of the present invention, the molar amount of ammonia / ammonium exceeds the equivalent molar amount of the anion by at least 20%. In another preferred embodiment, the molar amount of ammonia / ammonium exceeds the equivalent molar amount of the anion by at least 25%. Further preferred embodiments include wherein the molar amount of ammonia / ammonium exceeds the equivalent molar amount of the anion by at least 33%, at least 50%, at least 100%, at least 200% or at least 300%.

[0013] According to a preferred embodiment of the present invention, a method for producing a biocide is provided, the method comprising the steps of: providing a solution of a hypochlorite oxidant; providing a composition, the composition comprising: an ammonium salt, including ammonium and an anion; ammonia water; and sodium bicarbonate; wherein a total molar amount of ammonia and ammonium in the composition exceeds an equivalent molar amount of the anion in the composition by at least 10%; wherein the equivalent molar amount of the anion is a molar amount of the anion multiplied by its valence; and mixing the solution of the hypochlorite oxidant with the composition.

[0014] According to a preferred embodiment of the present invention, the hypochlorite oxidant is sodium hypochlorite. Preferably, the solution of the hypochlorite oxidant has a concentration in a range of about 1000 to about 20000 ppm, more preferably in a range of about 3000 to about 10000 ppm, and most preferably in a range of about 3500 to about 7000 ppm.

[0015] Preferably, the ammonium salt is selected from the group consisting of ammonium bicarbonate, ammonium bromide, ammonium carbamate, ammonium carbonate, ammonium chloride, ammonium phosphate, ammonium sulfamate and ammonium sulfate. More preferably, the ammonium salt is selected from the group consisting of ammonium bromide, ammonium carbamate, ammonium chloride and ammonium sulfate. Most preferably, the ammonium salt is selected from the group consisting of ammonium bromide and ammonium carbamate.

[0016] According to a preferred embodiment of the present invention, the composition is prepared by the steps of: mixing an ammonium salt stock solution, an ammonia stock solution and the sodium bicarbonate to form a mixture; and diluting the mixture with water or with a solution of the hypochlorite oxidant. The ammonium salt stock solution preferably has a concentration in a range of about 15% by weight (w / w) to about 50% by weight (w / w), and more preferably has a concentration in a range of about 20% by weight (w / w) to about 35% by weight (w / w).

[0017] Preferably, the aqueous ammonia stock solution has a concentration in the range of about 4% by weight (w / w) to about 28% by weight (w / w), and more preferably a concentration of about 8.33% by weight (w / w). The ammonium salt stock solution and the aqueous ammonia stock solution are preferably equimolar. Preferably, a molar ratio of the ammonium salt to the aqueous ammonia in the mixture is in the range of about 1:10 to about 10:1, more preferably in the range of about 1:3 to about 3:1.

[0018] According to a preferred embodiment of the present invention, the concentration of the sodium bicarbonate in the mixture is in a range of about 0.2% weight concentration (w / v) to about 10% weight concentration (w / v), more preferably in a range of about 1% weight concentration (w / v) to about 5% weight concentration (w / v). Preferably, the method further includes the step of monitoring a control parameter during the mixing step. The control parameter is preferably selected from the group consisting of pH, oxidation-reduction potential (ORP), conductivity, dissolved oxygen saturation and ORP / pH ratio. In a preferred embodiment, the control parameter is the ORP / pH ratio.

[0019] According to another preferred embodiment, the control parameter is the conductivity. Preferably, the mixing includes adding a solution of the hypochlorite oxidant to the composition; and when the conductivity reaches a relative maximum value, stopping the addition of the solution of the hypochlorite oxidant. Preferably, the conductivity reaches a relative minimum value before reaching the relative maximum value. In a preferred embodiment, the pH of the biocide is maintained below 12.5. DETAILED DESCRIPTION

[0020] As described in published European Patent Publication No. 0517102, the contents of which are incorporated herein by reference, biofouling in circulating water is a well-known problem caused by algae, fungi, bacteria and other simple life forms in the circulating water. The patent publication describes how to control biofouling in high chlorine demand water bodies by mixing two components, one of which is an oxidant and the other is an ammonium salt, and adding the mixture to the water system to be treated substantially immediately. This produces the active biocidal component described therein. A large number of examples of oxidants and ammonium salts are described in the patent publication.

[0021] However, one problem encountered with this method of treating liquids to inhibit biological growth is that the concentrated active biocidal ingredients are chemically very unstable and, once formed, decompose rapidly, causing the pH to drop rapidly. This is particularly true for active biocidal ingredients extracted from ammonium bromide, because decomposition can undesirably form HOBr and other degradation byproducts. Therefore, when using conventional metering pumps and mixers, the active biocidal ingredients that are formed will quickly decompose and lose their effectiveness. In addition, although the pH range of such concentrated active biocides is theoretically 9.5 to 11.0, due to the rapid decomposition rate, the actual pH can be as low as 8.0. In addition, in order to reduce the decomposition rate, the supply of ammonium salt is too large.

[0022] In US 5,976,386 (the contents of which are incorporated herein by reference), a method and apparatus for producing a biocide is disclosed which maintains a constant ratio of oxidant / amine source, thereby avoiding the need to use excess amine source to stabilize the reaction product and maintaining a reproducible product that is substantially free of degradation products. The novel method described therein comprises effective in situ dilution of both the oxidant and the amine source, and simultaneous metering of the two dilutions into a conduit, and continuous mixing in a predetermined ratio to produce an active biocide component. The predetermined ratio is a ratio of amine to oxidant of at least 1:1.

[0023] As described in US 5,976,386, careful control of biocide formation is necessary. Biocide production processes use a multi-feed point system that requires individual control of each feed line because different pumps react differently to pressure changes and the pump feed rate depends on the water flow pressure. For any on-site process, online control is required to ensure that the correct product is produced with high yield and low by-products. In addition, the above patent further discloses that equimolar amounts of ammonium and hypochlorite are necessary to achieve optimal performance. The ingredients used to make biocides disclosed in US 7,837,883, such as sodium hypochlorite and ammonium carbamate (the contents of which are incorporated herein by reference), are unstable chemicals that degrade over time during use. Therefore, running the feed unit at a predetermined constant feed rate of these two reagents will produce different products. In addition, other parameters such as water temperature, excessive pH, excessive concentration of biocide produced, and water quality will exacerbate biocide degradation. If the alkalinity of the NaOCl is too high, serious problems can occur. Especially for biocides prepared with ammonium carbamate, it has been shown that producing the biocide with an excess of free ammonia can impair the efficacy of the biocide.

[0024] The use of pH as an indicator of the end point of the reaction of ammonium salts and sodium hypochlorite is disclosed in US 5,976,386. Adding hypochlorite to an ammonium salt solution increases the pH. However, after the equimolar point is reached and all the ammonium salt has reacted, the hypochlorite begins to degrade the biocidal MCA to form inorganic acids, which in turn lower the pH. Therefore, the pH can be used as an indicator of the end point. However, the pH is only an accurate indicator when the pH is relatively low. Since biocides are produced at relatively high pH values, other indicators are needed.

[0025] US 9,801,384 (the entire contents of which are incorporated herein by reference) discloses other parameters that can be used to indicate the endpoint of the reaction between an ammonium salt and a hypochlorite oxidant. Specifically, Oxidation-Reduction Potential (ORP), Conductivity, and Induction all show a relative minimum at the endpoint. Dissolved oxygen shows a constant value during the reaction and drops rapidly at the endpoint. These parameters have been shown to be effective in determining the endpoint of the reaction, given that if the endpoint is missed and an excess of hypochlorite is added, the result will be biocide decomposition, loss of efficacy, and the production of undesirable degradation byproducts.

[0026] Even when using precise amounts of ammonium salts, ammonium salts are relatively expensive ingredients. Ammonium salts are much more expensive than ammonia in aqueous solution, also known as ammonium hydroxide. Although it is the ammonium portion of the ammonium salt that reacts with hypochlorite to form the monochloramine biocide, and the ammonium counterion is thought to play no significant role in the biocidal activity, it has been found that biocides made with ammonia and hypochlorite have lower biocidal activity than biocides made with ammonium salts. Ammonia is also known to be used in large freshwater disinfection plants to produce chloramines. However, ammonia solutions present logistical problems in industrial applications due to their physical properties. The pH of ammonia solutions is so high that the monochloramine produced during the production process will degrade. In addition, ammonia is continuously lost from ammonia solutions, making ammonia solutions an impractical choice for most industrial applications. It would be economically advantageous to be able to replace at least part of an ammonium salt, such as ammonium bromide, ammonium carbamate, ammonium sulfate, or ammonium chloride, with ammonia without reducing the activity of the biocide produced therefrom. Reducing the counterion content can also alleviate other problems, such as biocides made from ammonium chloride that may be corrosive to chlorides, and biocides made from ammonium sulfate that may support sulfate-reducing bacteria.

[0027] The quality of the sodium hypochlorite solution is another issue in the manufacture of monochloramine biocides. Sodium hypochlorite is produced by the reaction of chlorine gas and sodium hydroxide. The resulting solution contains alkalinity in the form of residual sodium hydroxide. The alkalinity of sodium hypochlorite solutions is usually around 0.7 to 0.8%, but can vary dramatically from very low (0.1 to 0.3%) to extremely high (up to 3%). Low alkalinity affects the production of monochloramine from ammonium salts derived from strong acids, such as ammonium bromide, ammonium chloride, and ammonium sulfate. Excessive alkalinity may affect all ammonium salts, but particularly those derived from weak acids, such as ammonium carbamate and ammonium carbonate. Replacing part of the salt with ammonia can increase the tolerance of the ammonium salt to the alkalinity of the hypochlorite solution and significantly improve the efficacy of the biocide in practical applications.

[0028] According to a first embodiment of the present invention, a composition useful for producing a biocide is provided, the composition comprising ammonium salt, ammonia water and sodium bicarbonate.

[0029] The ammonium salt is preferably selected from ammonium bicarbonate, ammonium bromide, ammonium carbamate, ammonium carbonate, ammonium chloride, ammonium phosphate, ammonium sulfamate and ammonium sulfate. More preferably, the ammonium salt is selected from ammonium bromide, ammonium carbamate, ammonium chloride and ammonium sulfate. Particularly preferably, the ammonium salt is selected from ammonium bromide and ammonium carbamate. The ammonium salt is preferably provided in the form of an aqueous solution at a concentration of about 15 to 50% by weight (w / w), more preferably about 20 to 35% by weight (w / w).

[0030] The ammonia solution is preferably provided in the form of an aqueous solution at a concentration of about 4 to 28% by weight (w / w), more preferably about 8.33% by weight (w / w). The ammonium salt and the ammonia solution are mixed in a molar ratio of about 1:10 to 10:1, more preferably in a molar ratio of about 1:3 to 3:1, and more preferably in a ratio of about 1:3, 1:2, 1:1, 2:1 or 3:1. The ammonia solution and the ammonium salt solution are preferably equimolar, that is, the molar ratio is equal to the volume ratio.

[0031] Due to the addition of ammonia, the total molar amount of ammonia and ammonium is excessive relative to the molar amount of the anion of the ammonium salt. When the anion is a multivalent ion, such as a sulfate ion with a valence of 2 or a phosphate ion with a valence of 3, the molar amount of ammonium in the ammonium salt is two or three times the molar amount of the anion. Therefore, the excess ammonia / ammonium is measured relative to an equivalent molar amount of the anion, which is equal to the molar amount of the anion multiplied by the valence of the anion. In one embodiment, the molar amount of ammonia / ammonium exceeds about 10% relative to the equivalent molar amount of the anion of the ammonium salt. In other embodiments, the molar amount of ammonia / ammonium exceeds about 20%, about 25%, about 33%, about 50%, about 100%, about 200%, about 300%, or about 1000% relative to the equivalent molar amount of the anion of the ammonium salt.

[0032] Sodium bicarbonate is preferably added to the mixture of ammonium salt and aqueous ammonia in a solid form. The concentration of sodium bicarbonate in the composition is preferably 0.2 to 10% by weight (w / v), more preferably about 1 to 5% by weight (w / v), most preferably about 2% by weight (w / v) or about 2.7% by weight (w / v).

[0033] In the present specification, the term "about" before a numerical value refers to a range of 10% more or less than the numerical value.

[0034] The composition of the present invention is useful for preparing a monohaloamine biocide. The biocide is preferably prepared by mixing an ammonium salt composition with a monochlorate oxidant. Preferably, the mixing produces a reaction that produces monochloramine.

[0035] In one embodiment, the biocide is produced by a batch process. The batch process includes adding a pre-diluted hypochlorite oxidant solution to the composition of the present invention in batches while mixing. A control parameter can be monitored during the mixing process. In some embodiments, the control parameter is pH, and a local maximum in pH indicates that all ammonia and ammonium have reacted and further addition of hypochlorite will cause degradation of the biocide. In other embodiments, the control parameter is oxidation-reduction potential (ORP) or conductivity, and a local minimum in ORP or conductivity indicates that all ammonia and ammonium have reacted. When the composition includes ammonium carbamate and is initially diluted in sodium hypochlorite, the conductivity will reach a maximum value after a minimum value before the monochloramine is degraded. In another embodiment, the control parameter is dissolved oxygen saturation, which maintains a generally stable value throughout the reaction of ammonia / ammonium and hypochlorite and begins to decrease once the ammonia / ammonium is exhausted.

[0036] In the present invention, the composition to be reacted with hypochlorite contains a mixture of an ammonium salt extracted from a strong acid (such as ammonium bromide, ammonium chloride or ammonium sulfate) and aqueous ammonia, and the initial pH of the composition is higher than that of a composition not containing aqueous ammonia. Therefore, the change in pH and the maximum pH may be difficult to observe. It should be noted that although the pH of the composition composed of ammonium carbamate and aqueous ammonia in solution is higher than that of the ammonium carbamate solution alone, the pH of the composition is lower than the pH of the currently commercially available ammonium carbamate preparation composed of 8% sodium hydroxide.

[0037] In addition, the initial conductivity of the composition of the present invention is lower than that of the composition without ammonia. Therefore, as the ammonia content in the composition increases, it may be difficult to observe the minimum value of the conductivity. ORP shows a minimum value, but the minimum value is not as sharp as that of the solution lacking ammonia. In this case, the endpoint can be more easily observed using the ORP / pH ratio. Since ORP generally decreases with increasing pH, the ORP / pH ratio has a more easily observed minimum value and can be used as a control parameter. In addition, since ORP takes longer than pH to obtain a stable reading, using the ratio can improve accuracy, especially when the biocide is produced continuously. It is preferred to produce the biocide on site and use it immediately after production.

[0038] In another embodiment, the biocide is produced using a continuous process. In the continuous process, a hypochlorite solution and a solution of the composition of the present invention are continuously mixed in a mixer, and a control parameter is monitored online in the mixer or in a conduit downstream of the mixer, or measured in discrete samples taken from the mixer. The flow rate of one of the solutions is maintained constant while the flow rate of the other solution is varied to change the ratio of ammonia / ammonium to hypochlorite until the control parameter indicates that the desired ratio has been achieved. The biocide produced in the continuous process is preferably applied to a medium during production.

[0039] The hypochlorite oxidant can be any hypochlorite oxidant, such as an alkali metal or alkaline earth metal hypochlorite. The hypochlorite is preferably sodium hypochlorite, potassium hypochlorite or calcium hypochlorite. The most preferred hypochlorite is sodium hypochlorite.

[0040] To prepare the hypochlorite solution, a concentrated hypochlorite stock solution is preferably mixed with water to form a hypochlorite dilution. The hypochlorite dilution preferably has a concentration of about 1,000 to about 20,000 parts per million (ppm). More preferably, the hypochlorite solution has a concentration of about 3,000 to about 10,000 parts per million (ppm). Most preferably, the hypochlorite solution has a concentration of about 3,500 to about 7,000 parts per million (ppm). The hypochlorite solution is preferably diluted with water at about 8 to 18% by weight (w / w) of the stock solution immediately prior to use. If the biocide is formed in a continuous process, the hypochlorite dilution is preferably prepared in-line as needed.

[0041] The composition of the present invention is preferably diluted prior to mixing with the hypochlorite. In one embodiment, the composition is diluted in water to an ammonia / ammonium concentration of about 1,000 to about 50,000 parts per million (ppm), more preferably about 3,500 to about 10,000 parts per million (ppm). Most preferably, the composition is diluted so that equal volumes of the ammonia / ammonium composition and the hypochlorite dilution provide an equimolar mixture of ammonia / ammonium and hypochlorite. In another embodiment, the composition is diluted with a diluted hypochlorite solution. This embodiment is particularly suitable for compositions comprising ammonium carbamate. However, unlike previously known ammonium carbamate compositions, the composition of the present invention comprising ammonium carbamate and aqueous ammonia can be diluted with water. The diluted composition is preferably prepared immediately prior to use. When the biocide is formed in a continuous process, the diluted composition is preferably prepared in-line when needed.

[0042] Example

[0043] General approach

[0044] A sodium hypochlorite stock solution (about 12.5% ​​as Cl2) is diluted with deionized water to a concentration of about 6,000 to about 10,000 ppm as Cl2. A stock solution of about 5 to 10% by weight (w / w) ammonia is prepared from a commercially available 20 to 28% by weight (w / w) solution. An ammonium salt stock solution (20 to 35%) is mixed with the ammonia stock solution to prepare an ammonium salt composition. A volume of the composition is added to 50 milliliters (mL) of deionized water to an equimolar concentration of about 5,000 to about 10,000 ppm hypochlorite (as Cl2). When ammonium carbamate is used as the ammonium salt, 2.3 milliliters (mL) of the ammonium salt composition can be diluted in 30 milliliters (mL) of the diluted hypochlorite solution.

[0045] For the measurements of pH, ORP, conductivity, and dissolved oxygen, the diluted hypochlorite solution was titrated into the ammonium solution. In each case, the correct volume of hypochlorite found for the non-ammonia solution sample was used for all samples. When hypochlorite is titrated into ammonia / ammonium to form the biocide, the biocide concentration is equal to the hypochlorite concentration added and varies throughout the titration as the volume of hypochlorite added changes. Therefore, using the same volume of hypochlorite for each sample ensures a constant biocide concentration. This is also confirmed by the constant residual chlorine at time 0. The dissolved oxygen measurements confirm that the biocide has not degraded. The biocide was then diluted 10 times and further diluted to the final concentration.

[0046] E. coli and Bacillus were grown in LB medium, washed with phosphate buffered saline (PBS), and concentrated to approximately 2×10 in 40 mL of PBS. 7 Up to 2x10 8 The total number of bacterial colonies per milliliter (cfu / mL). In some tests, glucose (about 5%) was added to the washed samples to ensure the removal of residual free chlorine in the event of partial degradation of the biocide and to simulate the actual situation of microbial growth in food while the biocide was added. Mixed microbial communities grown from wastewater samples were also tested.

[0047] A portion of the diluted biocide was added to the bacteria to a final concentration of 0.4 to 1.5 ppm (as Cl2). The residual chlorine in the deionized water was measured at the beginning of each test, and the residual chlorine in the test solution after the microbial incubation was measured after about 60 minutes. The samples were shaken at 25°C for 60 minutes and then deactivated with 50 microliters (μL) of sodium thiosulfate (2%). The samples were diluted 10 times, about 5 or 6 times, cultured with LB (Lysogeny Broth) agar, and cultured at 37°C for 48 hours.

[0048] Example 1

[0049] Stock solutions 1 to 5 were prepared by mixing different volumes of ammonium bromide (35% by weight solution) and aqueous ammonia (8.33% by weight solution) as listed in Table 1. The pH of each solution was measured. Biocides were prepared according to the general method described above and added to Bacillus samples at a final concentration of 0.5 ppm (as Cl2). Table 2 lists the residual chlorine and survival counts after biocide treatment.

[0050] The results showed that the biocide efficacy decreased as the amount of ammonium bromide used decreased. Pure ammonium bromide without ammonia had the highest efficacy despite lower residual chlorine.

[0051] Table 1:

[0052]

[0053] Table 2:

[0054]

[0055] Example 2

[0056] Stock solutions 1 to 4 were prepared by mixing different volumes of sodium bromide (36.8% by weight solution) with a fixed volume of aqueous ammonia (8.33% by weight solution) and then adding water to the fixed volumes listed in Table 3. The pH of each solution was measured. The biocide was prepared according to the general method above and added to the Bacillus sample at a final concentration of 1.0 ppm (as Cl2). Table 4 lists the residual chlorine and survival counts after biocide treatment.

[0057] Table 3:

[0058]

[0059] Table 4:

[0060]

[0061] The above results show that as the bromide content decreases, the efficacy of the biocide decreases. This example demonstrates that the decrease in efficacy shown in Example 1 is not related to an increase in the pH of the formulation.

[0062] Example 3

[0063] Stock solutions 1 to 5 were prepared by mixing different volumes of ammonium bromide (35% by weight solution) and ammonium chloride (19.1% by weight solution) as listed in Table 5. The pH of each solution was measured. Biocides were prepared according to the general method described above and added to the Bacillus samples at a final concentration of 1.0 ppm (as Cl2). Table 6 lists the residual chlorine and survival counts after biocide treatment.

[0064] The results showed that the biocide efficacy decreased as the amount of ammonium bromide was reduced. Since the pH of all samples was low, the decrease in activity could not be attributed to changes in pH.

[0065] Table 5:

[0066]

[0067] Table 6:

[0068]

[0069] Example 4

[0070] Stock solutions 1 to 4 were prepared by mixing different volumes of ammonium carbamate (20% by weight solution) and aqueous ammonia (4.8% by weight solution) as shown in Table 7. The pH and conductivity of each solution were measured. The biocide was prepared according to the general method described above and added to the Bacillus sample at a final concentration of 0.8 ppm (as Cl2). The Bacillus sample contained 5% glucose. Table 8 lists the residual chlorine and viable counts after biocide treatment.

[0071] Table 7:

[0072]

[0073] Table 8:

[0074]

[0075] The above results show that the efficacy of the biocide decreases with decreasing ammonium carbamate content. In the presence of glucose, the chlorine demand increases significantly. There is no direct interaction between the biocide and glucose. The high demand is due to the intense microbial activity in the presence of glucose. Therefore, glucose makes the culture more resistant to biocides and more similar to real-life activities.

[0076] Example 5

[0077] Stock solutions 1 to 5 were prepared by mixing different volumes of ammonium bromide (35% by weight solution) and aqueous ammonia (8.33% by weight solution) as listed in Table 9. Sodium bicarbonate was added to each stock solution at a concentration of 2.7% by weight (w / v). The pH of each solution was measured. Biocides were prepared according to the general method described above and added to the Bacillus samples at a final concentration of 1.0 ppm (as Cl2). The Bacillus samples contained 5% glucose. Table 10 lists the residual chlorine and survival counts after biocide treatment.

[0078] Table 9:

[0079]

[0080] Table 10:

[0081]

[0082] The above results show that the addition of a small amount of sodium bicarbonate to the ammonium salt can mitigate the effect of bromide removal shown in Example 1 above.

[0083] Example 6

[0084] Stock solutions 1 to 6 were prepared by mixing different volumes of ammonium bromide (35% by weight solution) and aqueous ammonia (8.33% by weight solution) as listed in Table 11. Sodium bicarbonate was added to solutions 2 to 6 at a concentration of 2.7%. The pH of each solution was measured. Biocides were prepared according to the general method described above and added to the E. coli samples at a final concentration of 1.0 ppm (as Cl2). The E. coli samples contained 5% glucose. Table 12 lists the residual chlorine and survival counts after biocide treatment.

[0085] Table 11:

[0086]

[0087] Table 12:

[0088]

[0089]

[0090] The above results show that adding a small amount of sodium bicarbonate to the ammonium salt can mitigate the effect of bromide removal shown in Example 1 above. The performance of the 1:1 mixture of ammonium bromide and ammonia water is better than the pure ammonium bromide sample without sodium bicarbonate.

[0091] Example 7

[0092] Stock solutions 1 to 6 were prepared by mixing different amounts of sodium bicarbonate into a mixture of equal volumes of ammonium bromide (35% by weight solution) and aqueous ammonia (8.33% by weight solution) as listed in Table 13. The pH and conductivity of each solution were measured. The biocide was prepared according to the general method described above and added to the E. coli samples at a final concentration of 1.0 ppm (as Cl2). The E. coli samples contained 5% glucose. Table 14 lists the residual chlorine and viable counts after biocide treatment.

[0093] Table 13:

[0094]

[0095] Table 14:

[0096]

[0097]

[0098] The pH of the mixture decreased slightly with increasing sodium bicarbonate buffering, but overall, the effect on the pH of the ammonium bromide / ammonia mixture was minimal. There was also no substantial effect on the conductivity of the formulated mixture. The improvement in efficacy was related to the sodium bicarbonate concentration, with the best effect occurring at a sodium bicarbonate feed rate of 2% by weight (w / v) in the ammonium bromide / ammonia mixture. The higher the sodium bicarbonate concentration, the lower the efficacy.

[0099] Example 8

[0100] Stock solutions 1 to 5 were prepared by mixing different volumes of ammonium chloride (19.1% by weight solution) and aqueous ammonia (8.33% by weight solution) as listed in Table 15. Sodium bicarbonate was added to solutions 2 to 5 at a concentration of 2.7% by weight (w / v). The pH and conductivity of each solution were measured. Biocides were prepared according to the general method described above and added to a sample of microorganisms (MO) isolated from domestic sewage at a final concentration of 1.5 ppm (as Cl2). Table 16 lists the residual chlorine and survival counts after biocide treatment.

[0101] The results showed that adding a small amount of sodium bicarbonate to ammonium salts can improve the biocidal activity. The sample of ammonium chloride and ammonia water mixed in a ratio of 1:1 performed the same as the pure ammonium chloride sample without sodium bicarbonate, while the sample of ammonium chloride and ammonia water mixed in a ratio of 3:1 performed better.

[0102] Table 15:

[0103]

[0104]

[0105] Table 16:

[0106]

[0107] Example 9

[0108] Stock solutions 1 to 6 were prepared by mixing different volumes of ammonium carbamate (20% by weight solution) and aqueous ammonia (8.33% by weight solution) as listed in Table 17. Sodium bicarbonate was added to solutions 2 to 6 at a concentration of 2.7% by weight (w / v). The pH and conductivity of each solution were measured. Biocides were prepared according to the general method described above and added to samples of microbial mixture (MO) isolated from domestic sewage at a final concentration of 1.5 ppm (as Cl2). Table 18 lists the residual chlorine and viable counts after biocide treatment.

[0109] The results showed that adding a small amount of sodium bicarbonate to the ammonium salts could mitigate the effects of carbamate removal shown in Example 4 above. The sample containing a 1:1 mixture of ammonium carbamate and ammonium hydroxide had the best effect.

[0110] Table 17:

[0111]

[0112]

[0113] Table 18:

[0114]

[0115] Example 10

[0116] Stock solutions 1 to 6 were prepared by mixing different amounts of sodium bicarbonate with aqueous ammonia (8.33% w / w solution) as listed in Table 19. The pH and conductivity of each solution were measured. Biocides were prepared according to the general method described above and added to the mixed culture samples at a final concentration of 1.0 ppm (as Cl2). The mixed culture samples contained 5% glucose. Table 20 lists the residual chlorine and survival counts after biocide treatment.

[0117] Due to the properties of ammonia, this scenario is not practical for industrial applications, but it is an interesting theoretical example. The effect of increasing sodium bicarbonate concentration on the formulation pH and conductivity is clear. The overall efficacy of ammonia alone is not very high, but the effect of adding sodium bicarbonate is clear and similar to the trend of ammonium salts.

[0118] Table 19:

[0119]

[0120] Table 20:

[0121]

[0122] Example 11

[0123] Stock solutions 1 to 5 were prepared by mixing different volumes of ammonium carbamate (20% w / w solution) and aqueous ammonia (8.33% w / w solution) as listed in Table 21. 2.3 mL of each sample was diluted with 30 mL of 5000 ppm (as Cl2) sodium hypochlorite solution. Sodium hypochlorite was added when measuring pH, conductivity, and ORP. Solution 1 showed an error in the measurement.

[0124] Table 21:

[0125]

[0126] Table 22 shows the results of the conductivity measurements. It is expected that the conductivity will first reach a minimum value and then a maximum value. The maximum value of the conductivity for each solution is shown in bold. As the amount of ammonia increases, the conductivity changes less and the maximum value occurs earlier. Therefore, conductivity becomes an unfeasible control parameter.

[0127] Table 22:

[0128]

[0129]

[0130] Table 23 shows the results of the pH measurements. The maximum pH value for each solution is shown in bold. Although a maximum value was observed for each solution, it became less sharp and more difficult to observe as the amount of ammonia increased, and therefore could not be used as a control parameter. In addition, it can be seen that no maximum value was observed when the amount of hypochlorite added was consistent.

[0131] Table 23:

[0132]

[0133]

[0134] Table 24 shows the results of the ORP measurements. The minimum ORP values ​​for each solution are shown in bold. Although a minimum was observed for each solution, the ORP minimum became less sharp and more difficult to observe as the amount of ammonia increased. In addition, accurate measurement of the ORP requires a certain amount of equilibration time after the addition of hypochlorite to the ammonium salt formulation. In the laboratory setting described in this article, such an equilibration time is available. However, when producing biocides in the field using a continuous process, such as the process described in US 9,801,384, there is no time for equilibration. Therefore, it may be difficult to observe small differences in ORP between biocides made using ammonia.

[0135] Table 24:

[0136]

[0137] Table 25 shows a new parameter, the ratio of ORP / pH. This parameter has a minimum value that is consistent and observable in all samples. Therefore, it is a useful parameter for controlling biocide production even under conditions where pH or ORP alone cannot be used. Generally, ORP decreases and pH increases before the reaction endpoint, so using the ORP / pH ratio can magnify the changes in the individual parameters and make the endpoint easier to observe.

[0138] Table 25:

[0139]

[0140]

[0141] Example 12

[0142] Stock solutions 1 to 6 were prepared by mixing different volumes of ammonium carbamate (20% by weight solution) and aqueous ammonia (8.33% by weight solution) as shown in Table 26. Sodium bicarbonate was added to solutions 2 to 6 at a concentration of 2.7% by weight (w / v). A sample of each solution was diluted with 50 ml of deionized water and sodium hypochlorite was added while measuring pH, conductivity, and ORP. Conductivity was not found to be a useful control parameter.

[0143] Table 26:

[0144]

[0145] Table 27 shows the results of the pH measurements. The maximum pH value for each solution is shown in bold. Although a maximum value was observed for each solution, it became less sharp and more difficult to observe as the amount of ammonia increased, and therefore could not be used as a control parameter. In addition, it can be seen that no maximum value was observed when the amount of hypochlorite added was consistent.

[0146] Table 27:

[0147]

[0148] Table 28 shows the ORP measurement results. The ORP minimum for each solution is shown in bold. Although each solution has a minimum, the ORP minimum becomes less sharp and more difficult to observe as the amount of ammonia increases.

[0149] Table 29 shows a new parameter, the ratio of ORP / pH. The minimum value of this parameter is consistent and observable in all samples. Therefore, this is a useful parameter for controlling biocide production even under conditions where pH or ORP alone cannot be used. Generally, ORP will decrease and pH will increase before the reaction endpoint, so using the ORP / pH ratio can magnify the changes in each parameter and make the endpoint easier to observe.

[0150] Another important result to note is that, while the previously known ammonium carbamate solution containing 8% sodium hydroxide (NaOH) could only be used to prepare the biocide by diluting the ammonium carbamate solution in a dilute hypochlorite solution, the present composition can also be used to prepare the biocide by diluting the composition in water.

[0151] Table 28:

[0152]

[0153] Table 29:

[0154]

[0155]

[0156] Example 13

[0157] Stock solutions 1 to 6 were prepared by mixing different volumes of ammonium bromide (35% by weight solution) and aqueous ammonia (8.33% by weight solution) as listed in Table 30. Sodium bicarbonate was added to solutions 2 to 6 at a concentration of 2.7% by weight (w / v). A sample of each solution was diluted with 50 ml of deionized water and sodium hypochlorite was added while measuring pH, conductivity, and ORP. Conductivity was found not to be a useful control parameter.

[0158] Table 30:

[0159]

[0160] Table 31 shows the results of the pH measurements. The maximum pH value for each solution is shown in bold. Although a maximum value was observed for each solution, as the amount of ammonia increased, the pH maximum became less sharp and more difficult to observe, making it an unfeasible control parameter.

[0161] Table 31:

[0162]

[0163] Table 32 shows the ORP measurement results. The ORP minimum for each solution is shown in bold. Although each solution has a minimum, the ORP minimum becomes less sharp and more difficult to observe as the amount of ammonia increases.

[0164] Table 32:

[0165]

[0166]

[0167] Table 33 shows a new parameter, the ratio of ORP / pH. This parameter has a minimum value that is consistent and observable in all samples. Therefore, this is a useful parameter for controlling biocide production even under conditions where pH or ORP alone cannot be used. Generally, ORP will decrease and pH will increase before the reaction endpoint, so using the ORP / pH ratio can magnify the changes in the individual parameters and make the endpoint easier to observe.

[0168] Table 33:

[0169]

[0170]

[0171] Example 14

[0172] Stock solutions 1 to 6 were prepared by mixing different volumes of ammonium chloride (19.1% by weight solution) and aqueous ammonia (8.33% by weight solution) as shown in Table 34. Sodium bicarbonate was added to solutions 2 to 6 at a concentration of 2.7% by weight (w / v). A sample of each solution was diluted with 50 ml of deionized water and sodium hypochlorite was added while measuring pH, conductivity, and ORP. Conductivity was found not to be a useful control parameter.

[0173] Table 34:

[0174]

[0175] Table 35 shows the results of the pH measurements. The maximum pH value for each solution is shown in bold. Although a maximum value was observed in each solution, as the amount of ammonia increased, the pH maximum became less sharp and more difficult to observe, making it an unfeasible control parameter.

[0176] Table 36 shows the ORP measurements. The minimum ORP value for each solution is shown in bold. Although each solution has a minimum value, the ORP minimum becomes less sharp and more difficult to observe as the amount of ammonia increases.

[0177] Table 37 shows a new parameter, the ratio of ORP / pH. The minimum value of this parameter is consistent and observable in all samples. Therefore, this is a useful parameter for controlling biocide production even under conditions where pH or ORP alone cannot be used. Generally, ORP decreases and pH increases before the reaction endpoint, so using the ratio of ORP / pH can magnify the changes in the individual parameters and make the endpoint easier to observe.

[0178] Table 35:

[0179]

[0180] Table 36:

[0181]

[0182]

[0183] Table 37:

[0184]

[0185]

[0186] Example 15

[0187] Stock solutions 1 to 6 were prepared by mixing different volumes of ammonium carbamate (20% by weight solution) and aqueous ammonia (8.33% by weight solution) as shown in Table 38. Sodium bicarbonate was added to solutions 2 to 6 at a concentration of 2.7% by weight (w / v). A comparative solution 0 was a 20% by weight (w / w) ammonium carbamate formulation including 8% by weight (w / w) sodium hydroxide (NaOH). The pH and conductivity of each solution were measured. The biocide was prepared according to the general method described above and added to the E. coli sample at a final concentration of 0.5 ppm (as Cl2). Table 39 lists the residual chlorine and survival counts after biocide treatment.

[0188] Table 38:

[0189]

[0190] Table 39:

[0191]

[0192]

[0193] These results show that the biocide formed by the composition of ammonium carbamate, ammonia and sodium bicarbonate is at least as effective as the formulation of ammonium carbamate and sodium hydroxide. The composition of the present application has the advantage of having a lower pH and being easier to handle relative to the commercial formulation.

[0194] Solutions 1 and 2 did not contain ammonia and differed only in that solution 2 contained sodium bicarbonate. Solution 2 performed better than solution 1 in reducing E. coli. When added at a rate of 1 ppm (as Cl2), solution 1 had a microbial count of 1.10E+02, while no microorganisms were found in samples treated with solution 2. This shows that sodium bicarbonate can enhance the activity of biocides formed from ammonium salts even in the absence of ammonia.

[0195] To understand this effect, we investigated the control parameters for biocide formation. In solution 1, the pH reached a maximum and the ORP reached a minimum after adding 140 mL of sodium hypochlorite. For solution 2, which contained sodium bicarbonate, the pH reached a maximum and the ORP reached a minimum after adding 150 mL of sodium hypochlorite. This shows that for the solution containing bicarbonate, more ammonia reacted with the hypochlorite, resulting in a higher concentration of biocide.

[0196] Example 16

[0197] The biocide was prepared by titrating low alkalinity sodium hypochlorite into an ammonium bromide solution (about 4500 ppm). The results in Table 40 below show that at low alkalinity, the biocide degrades during production and it is impossible to reach the isomolar point because the pH is low and even excess ammonium bromide will degrade quickly. The composition of the present invention can alleviate this problem because the pH of the composition is higher than the pH of the ammonium bromide solution.

[0198] Table 40:

[0199]

[0200] Example 17

[0201] The biocide was prepared by titrating a commercial sample of high alkalinity sodium hypochlorite with a 19.5% by weight (w / w) amino acid ammonium solution containing 8% sodium hydroxide while measuring pH, ORP and conductivity. The sodium hypochlorite titrant was prepared by diluting 6.6 ml of the commercial solution with 100 ml of deionized water. As can be seen in Table 41, the ORP / pH ratio, which was expected to decrease, actually increased with increasing pH, indicating that the biocide was degrading even with an excess of ammonium carbamate relative to sodium hypochlorite and a high pH. The conductivity was also very high due to the additional alkalinity and reached a maximum value before the true endpoint of the reaction due to continued degradation. The composition of the present invention can alleviate this problem because the pH of the composition is lower than that of the ammonium carbamate solution containing 8% sodium hydroxide and the conductivity is also lower.

[0202] Table 41:

[0203]

[0204] Example 18

[0205] To further illustrate the advantages of the present invention over an ammonium carbamate solution containing 8% sodium hydroxide, two solutions were prepared. Solution 1 contained 20% ammonium carbamate and 8% sodium hydroxide. Solution 2 contained 15% by weight ammonium carbamate, 2.4% by weight ammonia, and 2.5% by weight sodium bicarbonate. 2.3 ml of each solution was diluted with 30 ml sodium hypochlorite, and more sodium hypochlorite was added while monitoring pH, conductivity, and ORP. The results for Solution 1 and Solution 2 are shown in Table 42 and Table 43, respectively.

[0206] Table 42:

[0207]

[0208] Table 43:

[0209]

[0210]

[0211] In solution 1, the conductivity maximum occurred at 80 ml hypochlorite, while in solution 2, the conductivity maximum occurred at 130 ml hypochlorite. The pH of the biocide prepared from solution 1 was higher, which obviously led to premature degradation of the biocide. In the biocide prepared from solution 2, the pH was kept below 12.5, which in turn slowed the degradation of the biocide and allowed a larger amount of biocide to be prepared with the same amount of ammonium carbamate. The composition consisting of ammonium carbamate, aqueous ammonia and sodium bicarbonate did not require the addition of sodium hydroxide (previously believed to be necessary to stabilize the ammonium carbamate), reducing the amount of ammonium carbamate required and making the biocide more stable.

[0212] It should be understood by those skilled in the art that the present invention is not limited to the contents specifically shown and described above. On the contrary, the scope of the present invention includes the combination and sub-combination of the various features described above, as well as modifications thereof that would occur to those skilled in the art when reading the above description and that are not in the prior art.

Claims

1. A composition for preparing a biocide, characterized in that: The composition comprises: Monoammonium salts, comprising ammonium and an anion; Ammonia; and Sodium bicarbonate; wherein a total molar amount of ammonia and ammonium in the composition exceeds an equivalent molar amount of the anion in the composition by at least 10%; The equivalent molar weight of the anion is one mole of the anion multiplied by its valence.

2. The composition according to claim 1, characterized in that: The ammonium salt is selected from the group consisting of ammonium bicarbonate, ammonium bromide, ammonium carbamate, ammonium carbonate, ammonium chloride, ammonium phosphate, ammonium sulfamate and ammonium sulfate.

3. The composition according to claim 1 or 2, characterized in that: The ammonium salt is selected from the group consisting of ammonium bromide, ammonium carbamate, ammonium chloride and ammonium sulfate.

4. The composition according to any one of claims 1 to 3, characterized in that: The ammonium salt is ammonium bromide.

5. The composition according to any one of claims 1 to 3, characterized in that: The ammonium salt is ammonium carbamate.

6. The composition according to any one of claims 1 to 5, characterized in that: The composition is an aqueous solution including the ammonium salt in a concentration ranging from about 4% by weight to about 36% by weight.

7. The composition according to any one of claims 1 to 6, characterized in that: The composition is an aqueous solution including the ammonium salt in a concentration ranging from about 5% by weight to about 27% by weight.

8. The composition according to any one of claims 1 to 7, characterized in that: The molar ratio of the ammonium salt to the aqueous ammonia is in a range of about 1:10 to about 10:

1.

9. The composition according to any one of claims 1 to 8, characterized in that: The molar ratio of the ammonium salt to the aqueous ammonia is in a range of about 1:3 to about 3:

1.

10. The composition according to any one of claims 1 to 9, characterized in that: The molar ratio of the ammonium salt to the aqueous ammonia is about 1:

3.

11. The composition according to any one of claims 1 to 9, characterized in that: The molar ratio of the ammonium salt to the aqueous ammonia is about 1:

2.

12. The composition according to any one of claims 1 to 9, characterized in that: The molar ratio of the ammonium salt to the aqueous ammonia is about 1:

1.

13. The composition according to any one of claims 1 to 9, characterized in that: The molar ratio of the ammonium salt to the aqueous ammonia is about 2:

1.

14. The composition according to any one of claims 1 to 9, characterized in that: The molar ratio of the ammonium salt to the aqueous ammonia is about 3:

1.

15. The composition according to any one of claims 1 to 14, characterized in that: The concentration of the aqueous ammonia is in a range of about 1% by weight to about 21% by weight.

16. The composition according to any one of claims 1 to 15, characterized in that: The concentration of the aqueous ammonia is in a range of about 2% by weight to about 7% by weight.

17. The composition according to any one of claims 1 to 16, characterized in that: The concentration of the sodium bicarbonate is in a range from about 0.2% by weight to about 10% by weight.

18. The composition according to any one of claims 1 to 17, characterized in that: The concentration of the sodium bicarbonate is in a range from about 1% by weight to about 5% by weight.

19. The composition according to any one of claims 1 to 18, characterized in that: The concentration of the sodium bicarbonate is about 2.7% by weight.

20. The composition according to any one of claims 1 to 19, characterized in that: The molar amount of ammonia / ammonium exceeds the equivalent molar amount of the anion by at least 20%.

21. The composition according to any one of claims 1 to 20, characterized in that: The molar amount of ammonia / ammonium exceeds the equivalent molar amount of the anion by at least 25%.

22. The composition according to any one of claims 1 to 21, characterized in that: The molar amount of ammonia / ammonium exceeds the equivalent molar amount of the anion by at least 33%.

23. The composition according to any one of claims 1 to 22, characterized in that: The molar amount of ammonia / ammonium exceeds the equivalent molar amount of the anion by at least 50%.

24. The composition according to any one of claims 1 to 23, characterized in that: The molar amount of ammonia / ammonium exceeds the equivalent molar amount of the anion by at least 100%.

25. The composition according to any one of claims 1 to 24, characterized in that: The molar amount of ammonia / ammonium exceeds the equivalent molar amount of the anion by at least 200%.

26. The composition according to any one of claims 1 to 25, characterized in that: The molar amount of ammonia / ammonium exceeds the equivalent molar amount of the anion by at least 300%.

27. A method for producing a biocide, characterized in that: The method comprises the steps of: providing a solution of a hypochlorite oxidant; A composition is provided, comprising: Monoammonium salts, comprising ammonium and an anion; Ammonia; and Sodium bicarbonate; wherein a total molar amount of ammonia and ammonium in the composition exceeds an equivalent molar amount of the anion in the composition by at least 10%; wherein the equivalent molar amount of the anion is one mole of the anion multiplied by its valence; and A solution of the hypochlorite oxidant is mixed with the composition.

28. The method of claim 27, wherein: The hypochlorite oxidant is sodium hypochlorite.

29. The method according to claim 27 or 28, characterized in that: The solution of the hypochlorite oxidant has a concentration in a range of about 1,000 to about 20,000 ppm.

30. The method according to any one of claims 27 to 29, characterized in that: The solution of the hypochlorite oxidant has a concentration in a range of about 3,000 to about 10,000 ppm.

31. The method according to any one of claims 27 to 30, characterized in that: The solution of hypochlorite oxidant has a concentration in a range of about 3500 to about 7000 ppm.

32. The method according to any one of claims 27 to 31, characterized in that: The ammonium salt is selected from the group consisting of ammonium bicarbonate, ammonium bromide, ammonium carbamate, ammonium carbonate, ammonium chloride, ammonium phosphate, ammonium sulfamate and ammonium sulfate.

33. The method according to any one of claims 27 to 32, characterized in that: The ammonium salt is selected from the group consisting of ammonium bromide, ammonium carbamate, ammonium chloride and ammonium sulfate.

34. The method according to any one of claims 27 to 33, characterized in that: The ammonium salt is selected from the group consisting of ammonium bromide and ammonium carbamate.

35. The method according to any one of claims 27 to 34, characterized in that: The composition is prepared by the steps of: mixing an ammonium salt stock solution, an aqueous ammonia stock solution and the sodium bicarbonate to form a mixture; and The mixture is diluted with water or with a solution of the hypochlorite oxidant.

36. The method of claim 35, wherein: The ammonium salt stock solution has a concentration in a range of about 15% by weight to about 50% by weight.

37. The method according to claim 35 or 36, characterized in that: The ammonium salt stock solution has a concentration in a range of about 20% by weight to about 35% by weight.

38. The method according to any one of claims 35 to 37, characterized in that: The aqueous ammonia stock solution has a concentration in a range of about 4% by weight to about 28% by weight.

39. The method according to any one of claims 35 to 38, characterized in that: The ammonia stock solution has a concentration of about 8.33% by weight.

40. The method according to any one of claims 35 to 39, characterized in that: The ammonium salt stock solution and the aqueous ammonia stock solution were equimolar.

41. The method according to any one of claims 35 to 40, characterized in that: A molar ratio of the ammonium salt to the aqueous ammonia in the mixture is in a range of about 1:10 to about 10:

1.

42. The method according to any one of claims 35 to 41, characterized in that: A molar ratio of the ammonium salt to the aqueous ammonia in the mixture is in a range of about 1:3 to about 3:

1.

43. The method according to any one of claims 35 to 42, characterized in that: The concentration of the sodium bicarbonate in the mixture is in a range from about 0.2% by weight to about 10% by weight.

44. The method according to any one of claims 35 to 43, characterized in that: The concentration of the sodium bicarbonate in the mixture is in a range from about 1% by weight to about 5% by weight.

45. The method of any one of claims 27 to 44, further comprising the step of monitoring a control parameter during said mixing step.

46. ​​The method of claim 45, wherein: The control parameter is selected from the group consisting of pH, oxidation-reduction potential (ORP), conductivity, dissolved oxygen saturation and ORP / pH ratio.

47. The method of claim 46, wherein: The control parameter is the ORP / pH ratio.

48. The method of claim 46, wherein: The control parameter is the conductivity.

49. The method of claim 48, wherein: The step of mixing comprises the steps of: adding a solution of the hypochlorite oxidant to the composition; and When the conductivity reaches a relative maximum value, the addition of the hypochlorite oxidant solution is stopped.

50. The method of claim 49, wherein: The electrical conductivity reaches a relative minimum value before reaching the relative maximum value.

51. The method according to any one of claims 27 to 50, characterized in that: The pH of the biocide was maintained below 12.5.

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