Method and Product for Removal of Chloramines, Chlorine and Ammonia from Aquaculture Water

Europaisches Patentamt European Patent Office © Publication number: 0 203 741 Office europeen des brevets A2

EUROPEAN PATENT APPLICATION

A process for neutralising chloramines, chlorine and ammonia in water, which comprises adding to the water a bisulfite selected from sodium formaldehydebisulfite and potassium formaldehydebisulfite, or one or more materials which react to form the bisulfite insitu. This invention relates to a method and product quantity of water is continuously withdrawn from for water quality management for aquaculturists. the structure. The water environment of the closed, More specifically, the invention relates to the si- recirculating system can be controlled with inten- multaneous removal of chloramines, chlorine and sive care and maintenance. The water quality of a ammonia which are toxic to aquatic life. closed, non-recirculating system is very difficult to The culture of aquatic organisms, also known control except by more or less natural means (i.e., as aquaculture, in the U.S. and elsewhere for food, photosynthetic process to provide oxygen and bac- recreation, education, research, and hobby pur- terial processes to convert toxic wastes). The non- poses is a fast growing industry. The world produc- recirculafing, flow-through water systems often tion from 1971 to 1978 of fishes, crustaceans and have problems similar to closed systems, but envi- molluscs raised for food exceeded 10 million ronmental control in flow-through systems is gen- pounds. In the U.S. alone these same species erally as difficult as in closed non-recirculating sys- exceeded 184 million pounds in 1980. If nonfood tems. In either system, the objective of successful baitfish and aquarium species were added to the water quality management is the removal or neu- U.S. production in 1980, then aquacultured animals tralization of toxic substances which stress cultured would represent more than 206 million pounds. aquatic life forms and thereby to add significantly This translates into a total commercial value of over to the production and profitability of aquaculture. 210 million dollars. In short, aquaculture is big Among the many compounds found in natural, business and its growth continues at a significant waste and potable waters which are toxic to aquatic rate. The profit potential in aquaculture has created organisms, ammonia (NH3), chlorine in the form of such incentives that its many enterprises and oper- hypochlorus acid (HOCI) and hypochlorites (OCI'), ations quickly outdistance the supporting sciences and chloramines (NH2CI, NHCI2) are among the and technologies This results, not only in produc- most toxic and ubiquitous. tion losses and failure to meet product demands, Ammonia is present in natural waters as a but also in heavy financial losses. result of animal metabolism, of proteins; urinary, Two areas in particular stand out as sources of fecal and respiratory wastes; and bacterial min- frustration and lost profits for aquaculturists. These eralization of nitrogenous bases. This means that are disease management and water quality man- the aquatic organisms (fishes, crustaceans, mol- agement. Although the present invention is particu- luscs, etc.) themselves contribute significant, toxic larly related to water quality management, it should pollutants to their own water. In waste water these be noted that chemotherapeutic treatment for dis- same sources, as well as technological wastes, ease management is enhanced when high stan- account for ammonia presence. Ammonia in pota- dards of water quality are maintained. ble water is due to the failure to remove it in the With fishes and other aquatic animals, just as purification process or due to the purposeful addi- with other animals and humans, if a proper, non- tion for quality control. In a review of management stressful environment is provided then the inci- practices, researcher Stephen Spotte (Fish and in- dence of disease conditions is all but eliminated. vertebrate culture, John Wiley & Sons, New York, Two major types of systems exist for raising aquat- 1979) observed that current evidence indicates that ic life. These are closed and open systems. There NH, is significantly more toxic than its ionic form, are two types of closed systems; the closed, recir- NH4+ (ammonium). Even if this were not true, to culating system, and the closed, non-recirculating attempt to control the factors such as pH, tempera- system. The closed, recirculating system, such as ture and salinity that effect the NH3:NH4+ ratio could a home aquarium, is characterized by a fixed vol- be more harmful and costly. Spotte suggested that ume of water which is continuously or intermittently management techniques be targeted to remove as circulated through a fish holding tank. The closed, many sources of ammonia as possible from the non-recirculating system, such as a farm pond, is culture water such as uneaten food, dead animals characterized by a fixed volume (usually greater and plants and to keep the densities of cultured than in the previous example) of water to which species moderate and to not allow the total ammo- fresh makeup water is added, as needed, such as nia level to exceed 0.13 ppm (0.13 mg NH. per for compensation for evaporation. In a non-recir- liter of culture water). The problem with Spotte's culating, flow-through system, such as a raceway suggestions is that for commercial aquaculturists used to raise trout, fresh makeup water is continuously fed to the fish holding structure while a like moderate densities of cultured animals are seldom The reduction in concentrations of these toxic profitable and for aquarium hobbyists there is al- components in water, when their initial introduction ways room for one more fish in an already over- cannot be controlled, is crucial in the culture, main- crowded aquarium. tenance and display of freshwater, brackish water - Other respected researchers have warned of (estuarine), and marine organisms. In addition, the the dangers of ammonia in aquaculture. The safe timely reduction in concentrations of these toxic level for salmonids such as trout and salmon is components is also desirable. considered to be from 0.005 to 0.02 ppm. As a In the case of chlorine a process of reductive predisposing factor in bacterial gill disease of cul- dechlorination is most often practiced. However, tured food fishes, ammonia levels over 0.3 ppm are granular activated carbon is also used as a chemi- considered dangerous. cal adsorbant to remove chlorine from water. Am- When the foregoing standards for water quality monia removal can be accomplished by adsorption are compared to ammonia levels which can be on zeolites like clinoptilolite and phillipsite and by encountered in both culture water and natural wa- bacterial nitrification. The efficiencies of these two ters, the serious nature of this problem can be processes are effected by contact time (i.e., how better appreciated. The ammonia levels in long the water is in contact with the adsorbant or wastewater can range up to and over 5000 ppm. In bacterial bed) and other conditions such as tem- aquarium and aquaculture systems it is not unusual perature, dissolved oxygen levels, the presence of to encounter total ammonia concentrations of be- interferring substances (i.e., certain antibiotics in tween 1.0 and 3.0 ppm. the case of nitrifying bacterial beds, and highly Another fish threatening substance is chlorine. surface active organics in the case of chemical Chlorine is most often present in water as a result adsorbants), and maintenance procedures (i.e., of disinfection processes. It is not found in natural cleaning routines) of the filters themselves. waters unless there has been contamination from Chloramines can be removed by reductive de- wastewater or potable water sources. Aquacultu- chlorination followed by adsorption or nitrification of rists and aquarists simply have no direct control the freed ammonia. over the quantity of chlorine, or associated Dechlorination has been shown to be a highly chloramines, introduced to municipal water sup- reliable process and one which works well under plies. However, no matter what the initial concen- most conditions found in culture water, the term tration of chlorine, or chloramines, it must be re- referring to the water used to maintain, grow or duced to zero before any water in which it is breed aquatic plants and animals. One problem present can be safely used for culture purposes. with this process presents itself when thiosulfates, Levels of chlorine from 0.2 to 0.3 ppm are rapidly S20, " (the substances used in the majority of toxic to fishes. The U.S. Environmental Protection commercially available dechlorinators), are used; Agency recommends an upper level of 0.003 ppm excess thiosulfate ion reacts with dissolved oxygen for continuous exposure by coldwater and warm- in water and inadvertent or purposeful overdosing water fishes. Chlorine levels in municipal water can result in a reduction of dissolved oxygen in supplies range up to 2.5 ppm. When used as a culture water which can in turn cause respiratory disinfectant agent for cleaning aquariums, the rec- stress in the cultured organisms. In addition, many ommended solution typically contains 50 ppm chlo- commercially available dechlorinators have been rine. Accordingly, the aquarium must be very thor- found to be inadequate for complete dechlorination oughly rinsed to remove any trace of the chlorine of even relatively lightly chlorinated (i.e., less than after cleaning. 4.0 ppm total chlorine) potable waters. The use of Chloramines are most often present in water granular activated carbon has been common and is for the same reasons as the presence of chlorine. most often employed in laboratories for the prep- However, some chloramines in natural and waste aration of chlorine-free culture water. Nevertheless, waters result from the chemical combination of a recent study details the problems associated with chlorine with the ammonia normally found in these using granular activated carbon alone as a method waters. The chloramine level in a given water can of dechlorinating water for aquatic toxicological range quite high to over 5000 ppm, but the levels studies. Stephen J. Mitchell and Joseph J. Cech, encountered in most municipal tap waters is in the Jr., 1983, "Ammonia-caused gill damage in chan- range of 0.5 to 4.0 ppm. Even the latter range nel catfish (Ictalurus punctatus): confounding ef- represents a deadly concentration level for aquatic fects of residual chlorine", Can. J., Fish. Aquat. life. Sci., 40(2), pp. 242-247. The elimination of chloramines (i.e., dech- Biological filters will maintain ammonia concentra- loramination) from water used for culture purposes tions at low levels, even in saline waters, but they has reached more creative levels. One method require a long start-up time (up to 21 days), are currently used is to dechlorinate with the usual slow to react to increased ammonia loads, and dechlorinators then remove the freed ammonia by require a relatively narrow range of operating con- adsorption on granular clinoptilolite placed in a ditions. Products which are combinations of dech- filtering device or by addition the finely divided, lorinators and ammonia adsorbants will not function powder, clinoptilolite directly to the water. In actual- in saline waters and cause a temporary cloudiness ity, most dechloramination is achieved by dech- in the treated water due to the dispersion of the iorinating in the usual way and allowing the ammo- finely divided adsorbant. nia to be oxidized by nitrifying bacteria. Just as Accordingly, aquaculture needs a safe and ef- with chlorine, granular activated carbon has been fective way to remove chloramines, chlorine and used to remove chloramines from water, but this ammonia which overcomes the limitations, dangers process has also been questioned by the Mitchell and shortcomings of the various techniques pres- and Cech study in 1983. The same study showed ently employed. The primary goal of this invention that partial dechlorination allowed the residual chlo- is to fulfill this need in the industry. rine to potentiate the toxic effects of ammonia on More specifically, an object of the invention is fish. to provide a product and method for the removal of The removal of ammonia released into water chloramines, chlorine and ammonia which, unlike when chloramines are dechlorinated is likewise existing zeolites and ion-exchange resins, functions problematical. Biological filtration is a process of as well in saline water as it does in freshwater bacterial conversion or nitrification of toxic ammo- treatment. nia and nitrite ions (NO2- to less toxic nitrate ions - Another object of the invention is to provide a (NO,7). Biological filtration, however, is easily inter- completely safe product and method for the re- rupted and inhibited, and the intermediate product, moval of chlorine, chloramine and ammonia which nitrite ions (NO,-), is significantly more toxic to is non-toxic to fishes, aquatic invertebrates, marine aquatic organisms than the precursor ammonia. and freshwater algaes, and aquatic plants. Until a biological filter bed is fully conditioned and Another object of the invention is to provide a properly functioning (an average of 21 days), there product and method for the removal of is a constant increase in the -concentration of the chloramines, chlorine and ammonia which does not nitrite ions until the precursor ammonia is reduced cause clouding in hard or soft water or in salt water below its inhibiting (to the nitrite converting as do products which contain insoluble zeolites. Nitrobacterspecies of bacteria) concentrations. Yet another object of the invention is to provide The removal of ammonia by adsorption has its a product and method for the removal of own set of problems. Among these are flow rate chloramines, chlorine and ammonia in which the and contact time, adsorbant grain size, tempera- time required for neutralization is greatly reduced ture, adsorbant capacity, and the concentration of from the time required by earlier techniques. With interfering ions such as sodium (Na+) and potas- this invention, neutralization times vary from one to sium (K+). Clinoptilolite has approximately 5% of five minutes for "free" chlorine (hypochlorites), ten the capacity in salt water that it exhibits in fresh- to thirty minutes for chloramines ("combined" chlo- water and, therefore, correspondingly larger quan- rine), and twelve minutes to one hour for free tities of this adsorbant are required for a salt water ammonia. application. An additional object of the invention is to pro- Commercial products do currently exist which vide a product and method for the removal of claim to remove or neutralize one or more of the chloramines, chlorine and ammonia which does not toxic substances chlorine, chloramines and ammo- react with dissolved oxygen in either freshwaters or nia. However, they all suffer from one or more of saline waters. the above described shortcomings. Simple dech- Another object of the invention is to provide a lorinators, if properly dosed will completely neutral- product and method for the removal of ize chlorine. These same dechlorinators will break chloramines, chlorine and ammonia which is not pH the chlorine-ammonia bonds in chloramines and dependent and functions equally well throughout neutralize the chlorine but will not neutralize the the "normal" pH range, 5.0 to 9.0, of waters in freed ammonia. Ammonia adsorbants, if used prop- which most aquatic life is found. erly will adsorb and remove ammonia from water, but will have no effect upon any chlorine present and they will not function properly in saline waters. Another object of the invention is to provide a stoichiometric amount of dichloramine and 12 product and method for the removal of times the stoichiometric amount of chlorine in the chloramines, chlorine and ammonia which is largely form of hypochlorites present in the water to be uninhibited by the presence of commonly used treated. antibiotics such as chloramphenicol, nitrofurans, Unless otherwise stated herein, indication of and sulfa drugs, or by the presence of antipar- parts or percentages are given on a weight basis. siticals such as copper sulfate, metronidazole and I have discovered that an alkali metal formal- formaldehyde. dehydebisulfite is unexpectedly effective and safe A further object of the invention is to provide a to neutralize chlorine, chloramine and ammonia product and method for the removal of from saline and fresh waters for use in aquaculture. chloramines, chlorine and ammonia which can be A pure alkali metal formaldehydebisulfite, a mixture combined with water conditioning chemicals such of alkali metal formaldehydebisulfites, or a mixture as other dechlorinators, electrolyte mixes, and of one or more alkali metal formaldehydebisulfites trace element mixes. with various diluents, carriers or other inert ingre- Yet a further object of the invention is to pro- dients can be utilized directly in dry or solution vide a product and method of the character de- form in untreated water to neutralize by chemical scribed which is safe, reliable and economical to reaction any aqueous chloramines, chlorine and effect removal of chloramines, chlorine and ammo- ammonia which may be present in order to render nia. the water nontoxic for aquatic life. Other and further objects of the invention, to- Neither the reaction mechanism, nor the reac- gether with the features of novelty appurtenant tion products, by which the phenomena of neu- thereto, will appear in the course of the following tralizing chloramines, chlorine and ammonia in wa- description of the invention. ter with an alkali metal formaldehydebisulfite is I have discovered that an alkali metal formal- understood. However, experimental research shows dehydebisulfite effectively neutralizes chloramines, reaction completion of sodium formaldehydebisul- chlorine and ammonia from saline and fresh waters fite and the representative target compounds in- for use in aquaculture. A pure alkali metal formal- cluding free chlorine in the form of sodium hy- dehydebisulfite, a mixture of alkali metal formal- pochlorite (NaOCI), free ammonia (NH3), and mon- dehydebisulfites, or a mixture of one or more alkali ochloramine (NH2CI) to eliminate the toxic effects of metal formaldehydebisulfites with various diluents, the target compounds in aquaculture. The results carriers or other ingredients can be utilized directly show that under conditions of varying pH, hard- in untreated water to neutralize by chemical reac- ness, and salinity that sodium formaldehydebisul- tion any aqueous chloramines, chlorine and ammo- fite was capable of simultaneously reducing the nia which may be present in order to render the concentrations of all three representative target water nontoxic for aquatic life. The water treatment compounds to safe levels. Further research in- product can be manufactured either in a dry form dicates effectiveness under representative aquacul- (i.e., powder, granule, flake, tablet, cake, pellet, ture working conditions by reducing free ammonia bolus, capsule) with or without additives, or in a levels in existing freshwater and marine aquarium water solution with or without other dissolved or water and by neutralizing free chlorine and suspended substances. chloramines in freshly drawn potable tap water. In summary, the invention relates to a process As used herein, the terms "remove" and for neutralizing chloramines, chlorine and ammonia "neutralize" are used interchangeably to refer to in water by adding an alkali metal formal- the discovered ability of alkali metal formaldehydebisulfite in a dry or solution form in which dehydebisulfites to render nontoxic to aquatic life the alkali metal formaldehydebisulfite is selected the chloramines, chlorine and ammonia existing in from the group consisting of sodium formal- natural and culture waters. dehydebisulfite and potassium formaldehydebisul- The alkali metal formaldehydebisulfites useful fite. In a preferred embodiment, the alkali metal in this invention include sodium formaldehydebisul- formaldehydebisulfite is sodium formaldehydebisulfite and potassium formaldehydebisulfite. The com- fite added in the amount at least equal to the pound sodium formaldehydebisulfite has the greater of the quantity required to react on a one to chemical formula HOCH2S03Na, and is also known one molecular basis with a reactant selected from as formaldehyde sodium bisulfite and sodium the group consisting of 4 times the stoichiometric hydroxymethane sulfonate. The compound potas- amount of ammonia, 12 times the stoichiometric amount of monochloramine, 10 times the sium formaldehydebisulfite has the chemical for- The alkali metal formaldehydebisulfite may be mula HOCH2SO3K, and is also known as formal- used directly for water treatment. As with many dehyde potassium bisulfite and potassium hydrox- process chemicals, however, proper performance ymethane sulfonate. of a consumer formulation is often best achieved The alkali metal formaldehydebisulfites may be by providing a dosage form which is easily applied utilized in the dry form with a variety of inert and only requires commonly available volumetric materials such as diluents, carriers, excipients, measuring devices such as teaspoons (1/6 fl.oz, lubricants, disintergrants, and colorants. A diluent - 4.93 mL), tablespoons (1/3 fi.oz., 9.86 mL) or cups (i.e., tricalcium phosphate) is an inert material used (8 ft.oz., 236.64 mL). Although weight measurement to reduce the concentration of an active material to of solids is routinely very accurate, it is quite achieve a desirable and beneficial effect. A carrier - uncommon for consumers to employ such mea- (i.e., salt) is an inert material used to deliver or surements when using water ' conditioning chemi- disperse an active material. Suitable diluents and cals and similar products. The use of pre-weighed carriers for use with alkali metal formaldehydebisul- unit dosages of a pure substance or its mixtures in fites include salt and other similar, non-reactive, the form of tablets, boluses, capsules or packets is neutral electrolytes such as sodium sulfate and the typical and preferred method to deliver dry potassium chloride, and nonelectrolytes and insolu- forms. Such method works quite well for this inven- ble salts such as starch, sugars, clays, and calcium tion. Equally satisfactory, however, is a formulation sulfate. An excipient (i.e., starch) is an inert ma- as a dry powder or granular mixture of a consis- terial used as a binder in tablets. Suitable ex- tency which readily lends itself to accurate and cipients for use with alkali metal formal- repeatable volumetric dosage measurements. dehydebisulfites include polymers and gums such To illustrate the foregoing principals with re- as cellulose gum and povidone, and starches. A spect to suitable formulations, the following dry lubricant (i.e., magnesium stearate) is an inert ma- forms of product represent convenient formulations terial used to reduce friction during filling or tablet- adapted for easy use by the lay consumer: ing processes. Suitable lubricants for use with alkali metal formaldehydebisulfites include fatty acid salts (1) Unit-dose tablet containing 1.18 grams of such as calcium stearate or magnesium stearate, active ingredient sodium formaldehydebisul- and paraffinic compounds and fatty acids such as fite and 0.80 grams of diluent salt and 0.02 paraffin wax and stearic acid. A disintergrant is an grams of lubricant magnesium stearate de- inert material that causes tablets and boluses to signed to treat 10 gallons (37.8 liters) of burst upon exposure to appropriate conditions. municipal water containing up to 2.5 ppm - Suitable disintergrants for use with alkali metal for- (2.5 mg/liter) of chlorine as monochloramine. maldehydebisulfites include polymers such as cross-linked povidone, and effervescent mixtures (2) Multi-dose package containing 1 pound - such as sodium bicarbonate/citric acid. A colorant (453.6 grams) of a mixture of 9.44 ounces - is an inert material which imparts color to another (267.6 grams) of sodium formaldehydebisul- material or mixture. Suitable colorants for use with fite and 6.56 ounces (186.0 grams) of fine alkali metal formaldehydebisulfites include lakes - blending salt which is to be dosed at the rate (i.e., organic pigments on an adsorptive inorganic of 1 teaspoonful (approximately 5 mL or 10 substrate) such as rose madder, and non-oxidizing grams) per 10 gallons (37.8 liters) of aquar- dyes such as acriflavine. ium water, either freshwater or marine, con- The pure, dry active alkali metal formal- taining up to 1.0 ppm (1.0 mg/liter) of free dehydebisulfite may be packaged in containers ammonia (NH3). such as bottles, boxes, nonporous bags, and drums The formulation of the aquaculture product in which serve to protect the integrity of the product solution form, whether by direct dissolution of the and to allow for appropriate dispensing. Other dry active ingredient or in situ synthesis of the product forms of the product for use in this invention in- by reaction of formaldehyde gas or solution with clude unit dose tablets, capsules, boluses or pack- sodium bisulfite solution at the the point of manu- ets. Individual dosage units may be weighed or facture or just prior to being added the water to be measured by bulk volume if supplied in the form of treated is inherently simple, convenient and in- powders, granules, pellets, or flakes. Larger unit expensive. Highly purified sodium formal- dose requirements, such as for ponds, lakes, or dehydebisulfite is commercially available in large streams can be applied as a dry-manufactured cake. quantities. It is easily and completely soluble in Unlike products containing mixtures of thiosul- water and produces a solution which is clear, color- fates and clinoptilolite, sodium formaldehydebisul- less, odorless and stable within a pH range of 6.0 fite solutions function in saltwater as easily as in to 8.0. freshwater, and there will be no clouding. The To illustrate the foregoing principals with re- sodium formaldehydebisulfite solution is of neces- spect to suitable liquid formulations, the following sity colorless because of its incompatibility with solution forms of product represent convenient for- arylmethane and other similar oxidizing dyes. mulations adapted for easy use by the lay con- Methylene blue, a sulfur-containing, oxidizing dye sumer: is stable in an sodium formaldehydebisulfite solution for a short period of time, but because of the (1) A two-part product consisting of a objectionable properties of this dye, it is not recom- 9.525% solution of formaldehyde (CH20) in mended as a coloring agent. water with or without suitable preservatives In the various product formulations of this in- and/or buffers (i.e., methanol, phosphate vention, the usual practices of cleanliness and sani- buffer) and a second solution of a 33.01% tation are to be followed as these relate to the solution of sodium bisulfite (NaHS03) in wa- conditions of mixing, packaging and storage. The ter. The two solutions to be combined, in purity and grades of the various ingredients includ- equal portions by weight, and used at the ing formaldehyde gas, formaldehyde solution, so- rate of 5 mL per 10 gallons (37.8 liters) to dium bisulfite, sodium formaldehydebisulfite, potas- treat pond water containing 1.0 ppm (1 sium formaldehydebisulfite, methanol, salt, starch, mg/liter) free ammonia. tableting excipients, tableting lubricants, cross- povidone, buffers and their components, colorants (2) A single solution containing 21.27% so- and dyes, diluents and carriers, and water may dium formaldehydebisulfite in water, to be vary from standard commercial or technical grades used at the rate of I teaspoon (approximately to the highly purified, reagent or pharmaceutical 5 mL) per 20 gallons (75.7 liters) for the grades. The physical forms of the various solid treatment of potable water containing 2.0 components may vary from ultra-fine powders to ppm (2.0 mg/liter) combined chlorine. granular and flake forms. Liquid components The consumer oriented single solution may be should be free from suspended or precipitated ma- used as a dose of 1 teaspoonful (4.93 mL) per 20 terial, but should such material be present it should gallons (75.7L) of water for neutralizing up to 4.0 be removed by suitable settling and decantation or ppm monochloramine measured as combined chlo- filtering. Any water should be similarly free of sus- rine, or 1 teaspoonful per 10 gallons (37.85 L) for pended or precipitated material as well as free neutralizing up to 1 ppm ammonia measured as from free or combined chlorine, including free ammonia. In each instance, the recommended chloramines, and free or ionized ammonia. In addi- dilution represents approximately 4 times the re- tion, the water must be free of other free halogens quired stoichiometric amounts of sodium formal- such as iodine (I) and bromine (Br) and their com- dehydebisulfite required to react with the pollu- bined forms which may reduce the final required tants. Such a product is perfectly capable of neu- concentration of the sodium formaldehydebisulfite. tralizing chlorine in the form of hypochlorites with- Neutralization or removal of potentially interfering out the addition of any other dechlorinator. Such a substances would be permissible prior to the addi- product would not be expected to neutralize any tion or formation of the sodium formaldehydebisul- ammonia present as the ammonium ion. However, fite. With observance of the foregoing, any potable this of course is relatively unimportant because of water source may be used in the manufacturing the non-toxic nature of the ionized form. Reaction process. with chlorine in both the "free" and "combined" All components used in the production of these forms can be expected to proceed as quickly as aquaculture products must be free from, or ren- with all-purpose water conditioners (i.e., complete dered free from, substances which may be toxic or within 10 minutes). The reaction with ammonia can otherwise detrimental to fish, aquatic invertebrates, be expected to take longer depending upon the aquatic algae plants and other aquatic life. initial concentration of the free ammonia. In usual Both acids and alkalies hasten the decomposi- practice, complete deamination can be expected tion of the sodium formaldehydebisulfite. Therefore, within 1 hour at an initial concentration of 1 ppm solutions of sodium formaldehydebisulfite must be ammonia. manufactured so that the final pH lies between 6.0 and 8.0. Dry formulations must be manufactured so that if the resultant mixture is hygroscopic, then molecular basis with a reactant selected from the decomposition of the sodium formaldehydebisulfite group consisting of 4 times the stoichiometric will not result due to an acidic or alkaline environ- amount of ammonia, 12 times the stoichiometric ment being created within the mixture. amount of monochloramine, 10 times the In typical production of a liquid form of this stoichiometric amount of dichloramine and 12 invention, the following parameters should be con- times the stoichiometric amount of chlorine in the sidered preferable but not essential. If dry sodium form of hypochlorites present in the water to be formaldehydebisulfite is to be used it should be of treated. photographic grade which has typically less than The invention is further exemplified with refer- 0.1% free formaldehyde and less than 0.1% un- ence to the following research examples investigat- combined sodium bisulfite and of powder form. If ing the parameters of the alkali metal formal- the sodium formaldehydebisulfite is to be formed dehydebisulfites for use in aquaculture and the by reaction, then 35-38% formaldehyde solution efficacy for neutralizing chloramines, chlorine and with no more than 15% methanol can be reacted ammonia from water to provide a safe treatment with photographic grade, powdered or granular so- program for aquatic life in culture water. dium bisulfite. Water should be completely deionized and have a pH of 6.5 to 7.5. The final solution is Example 1 to be clear, colorless and free from suspended or precipitated matter. Mixing and filling equipment Research was conducted to investigate the re- may desirably be fabricated from stainless steel or action between sodium formaidehydebisulfite - polyvinyl chloride. The liquid product can be pack- (hereinafter referred to as "SFB") and ammonia as aged and stored in polyethylene containers with represented by the following equation: polyethylene or polypropylene closures. The relative instability of formaidehydebisulfites in alkaline media does not recommend the use of the in situ reaction of formaldehyde solution with To test this reaction I prepared ammonia standards alkali sulfites, and the presence of amounts of from ammonium chloride and used the standard hydroxide ions (OH-) equimolar to the amounts of method of measuring for ammonia with an Orion alkali metal formaldehydebisulfites could be det- 901 lonalyzer. connected to a chart recorder and an rimental to aquatic -life in treated waters due to an ammonia specific-ion-electrode (hereinafter re- increase in pH which might result. ferred to as "SIE"). Two working solutions of SFB, As previously indicated, the reaction mecha- #1 SFB solution (120.85 g/L) and #2 SFB solution nism and reaction products are not completely (241.72 g/L) were prepared for use in the subse- understood in the reaction of alkali metal formal- quent reaction studies. The standard ammonia so- dehydebisulfite with chloramines, chlorine and am- lutions were made so that upon addition of 1 mL of monia in water. However, research indicates that ION sodium hydroxide (NaOH) concentrations of the reactants react on a one to one molecular basis 0.5 ppm, 1.0 ppm and 2.0 ppm (as NH3) were and this observation is utilized in formulating the produced. One-hundred milliliters of each standard amount of alkali metal formaldehyde bisulfite in a ammonia solution were pipetted, in tum, into 150- dry or solution form which is required for a speci- mL Fleakers, a Teflon-coated stirring bar was fied amount of pollutant found in the water to be placed in the Fleaker and gentle stirring was start- treated. Accordingly, as minimum effective quan- ed. The prepared and standardized SIE was placed tities, alkali metal formaldehydebisulfite must be into the solution and when a stable baseline was present in an amount at least equal to the greater achieved on the recorder, 1.0 mL of the NaOH of the quantity required to react on a one to one solution was pipetted into the solution. As soon as molecular basis with the stoichiometric amount of a stable reading was obtained on the instrument ammonia, the stoichiometric amount of monoch- and a new, stable baseline was achieved on the loramine, the stoichiometric amount of dichloramine recorder then an excess (1.0 mL) of the #1 SFB or the stoichiometric amount of chlorine in the form solution was added and any change in the mea- of hypochlorites present in the water to be treated. sured ammonia concentration was tracked on both It is naturally desirable, however, that the neutraliz- the instrument and the recorder with instrument ing agent be present in excess. In a preferred readings being noted on the recorder chart at ar- embodiment of the invention, the alkali metal for- bitrary intervals. maldehydebisulfite is sodium formaldehydebisulfite added in the amount at least equal to the greater of the quantity required to react on a one to one The results of the chemical tests suggest that tion of 1.0 ppm with a change in rate at 15.26 the reaction between ammonia and SFB even at minutes (concentration of approximately 0.65 ppm) high pH's is a concentration dependent, second as shown in Table 2. With reference to Table 3, order reaction. As such the reaction time is limited and with a 2.0 ppm initial ammonia concentration, a by the concentrations of both reactants. This 10% reduction was achieved at 4.88 minutes with a means that very low concentrations of ammonia - rate change at 14.1 minutes (concentration of ap- (less than 0.5 ppm) will exhibit very long reaction proximately 1.40 ppm) and an approximate 50% times. In my tests a 10% reduction in the initial reduction (1.06 ppm) was achieved at 33.16 min- concentration (0.5 to 0.45 ppm) took 15 minutes as utes. In each case, subsequent additions of the #1 illustrated in Table 1. A similar percentage reduc- SFB solution resulted in an increase in the reaction tion took only 3.68 minutes at an initial concentra- rate. silver nitrate solution were added. Then 10 drops of Example 2 totally deionized water were added to each tube and each tube, in tum, was swirled to mix. In three Additional tests were conducted to confirm the of the tubes, 25 drops of #2 SFB solution was reaction between SFB solutions and ammonia. In added to each. In the remaining tubes, 25 drops of the first test, an ad libidum solution of ammoniacal totally deionized water was added to each. Each silver nitrate was prepared by dissolving an un- tube was swirled to insure mixing of the contents, weighed quantity of silver nitrate (AgN03) in just and allowed to stand to observe any visible enough 6.ON ammonium hydroxide to produce a changes. clear colorless solution free of precipitate. Since it In the test series of the ammoniacal silver is known that any reduction in the slight excess of nitrate with the SFB solution the three tubes with- ammonia in this solution will result in the precipita- out added SFB solution showed no reaction during tion of an insoluble silver compound, it was as- the test which was terminated after 1 hour. The sumed that just such a precipitate would form if three tubes with added SFB solution showed an SFB or its solutions were added to the solution. immediate reaction (within 30 seconds); a white Side-by-side controls were used to confirm that precipitate was formed which coagulated readily any reaction was not due to some other variable upon additional swirling of the tubes. In addition, such as loss of ammonia from the solution to the the SFB-containing tubes exhibited only a slight atmosphere. Identical test tubes were " used. In musty odor while the untreated tubes exhibited a each of six tubes, 15 drops of the ammoniacal noticeably stronger and distinct ammonia odor. solution). When tested in a manner equivalent to This test showed that the SFB reacted to remove that of the #2 SFB solution above using 90 drops the ammonia allowing the formation of an insoluble of each solution, identical results were obtained silver precipitate compound. with solutions of ammoniacal cupric sulfate. In an additional test series, a combination solu- Example 3 tion of equal volumes of #3 SFB solution and KFB solution were substituted for the #2 SFB solution at In a test series further examining the ammonia the rate of 45 drops of each of the #3 SFB and and SFB reaction, 25 drops of 1.0 M cupric sulfate KFB solutions, added together, to solutions of am- solution was added to each of six identical test moniacal cupric sulfate. This combination solution tubes. Next, 25 drops of totally deionized water reacted in an identical manner as cited above for was added to each tube and each tube was swirled the #2 SFB solution. to insure mixing of the contents. Next, 15 drops of 6.ON ammonium hydroxide solution was added to Example 4 each tube to produce a solution of ammoniacal cupric sulfate. As with the ammoniacal silver ni- In the next test series, 15 drops of 6.0 N trate, any dissipation or removal of ammonia from ammonium hydroxide was added to each of six this solution will result in the precipitation of an test tubes. Next, 3 drops of bromthymol blue, insoluble copper compound. Finally, 50 drops of #2 U.S.P. test solution used as a pH indicator, was SFB solution was added to three of the six tubes, added to each tube, and each tube was swirled to and 50 drops of totally deionized water were added mix the contents. Each solution turned a char- to the remaining three tubes.Each tube was swirled acteristic blue color indicating an alkaline pH. Next, to mix the contents. 50 drops of #2 SFB solution was added to three of The series of tests with ammoniacal cupric the tubes and 50 drops of totally deionized water sulfate showed essentially the same results as the the the remaining three tubes. Each tube was test with ammoniacal silver nitrate. The color swirled to insure mixing of the contents and each change of the solutions and the color of the tube was stoppered with tightly fitting silicone rub- precipitate were more dramatic. In the SFB-con- ber stoppers and allowed to stand to observe any taining tubes, the clear, bright blue solution be- changes in the color of the solutions. One tube came turbid within 5 to 7 minutes and within 2 containing the added SFB solution and one tube hours the color of the solution changed to a very with just added water was periodically opened at pale blue and a copious amount (equivalent to intervals of every 15 minutes for the first 2 hours, approximately 1/3 the volume of the total liquid in then every hour for 6 additional hours, and smelled the tube) of blue-green precipitate had formed. The to test for the odor of ammonia. The other four control tubes exhibited no color changes or tubes remained unopened throughout the entire 8 precipitate formation during the test which termi- hours of the test. nated after 4 hours. As with the previous test Throughout the test, all tubes retained the color series, only a slight musty odor was detectable in indicating an alkaline pH. In the control tubes, the the SFB-containing tubes while in the control tubes stoppers were easily removed indicating no reduc- a strong and distinct ammonia odor was detectable. tion in the atmospheric pressure within the tubes. The same test parameters were employed in In the SFB-containing tubes, the stoppers in the which two different solutions were substituted for two tubes which remained unopened during the the #2 SFB solution. These two solutions were' 1) test had been pulled noticeably deeper into the an SFB solution (hereinafter "#3 SFB solution") in mouth of the tube to a depth of .5 to .7 centimeters which equal volumes of sodium bisulfite having a 1 greater than the stoppers in the other four tubes. M concentration as sulfur dioxide and a 1 M form- Greater effort was required to extract the stoppers aldehyde solution were mixed; and 2) a potassium from these two tubes. In the one SFB-containing formaldehydebisulfite (hereinafter "KFB") solution tube which was periodically opened for odor testing in which equal volumes of potassium metabisulfite there was no noticeable difference in the depth of (K2S20S) having a 1 M concentration as sulfur diox- the stopper or in the effort required to extract it at ide and a 1 M formaldehyde solution were mixed. the termination of the test. There was a clearly Both solutions were designed to be 0.5 M in the detectable difference in ammonia odor in the three respective alkali metal formaldehydebisulfite (i.e., SFB-containing tubes compared to the odor in the sodium in the former and potassium in the latter control tubes at the termination of the test. The reduction of the atmospheric pressure in the control tubes is indicative of the consumption of ammonia, which ordinarily has an appreciable vapor When an instrument reading of 1.00 ppm was pressure at room temperature. The initial odor of achieved, 1.0 mL of the #1 SFB solution was each tube was the characteristic pungent odor typi- added and any change was tracked on both the cal of ammonia solutions. instrument and the recorder with instrument readings being noted on the recorder chart ar arbitrary Example 5 intervals. In the chloramine reaction test, the readings as Research was conducted to investigate the re- shown in Table 4 indicated an increase from the action between sodium formaldehydebisulfite - "set" meter reading of 1.00 ppm to 1.46 ppm at (hereinafter referred to as "SFB") and monoch- 3.98 minutes at which time the measured con- loramine as represented by the following equation: centration of ammonia started decreasing. This is consistent with a first order dechlorination reaction followed by reaction with ammonia. As in previous Example 1, addition of more of the SFB solution The experiment was designed so that any reduc- resulted in an increased reaction rate. From the tion in either chlorine or ammonia concentrations or first point of recorded decrease in the ammonia both could be observed, rather than speculate as to concentration to the point of the second addition of the nature of the reaction products. I prepared a SFB solution, the rate was equivalent to approxi- standard monochloramine solution from 28% am- mately 0.91% decrease in ammonia per minute. monia solution and sodium hypochlorite solution so From the second addition to the third addition of that the resulting solution contained 1 ppm mon- SFB solution, the rate was approximately 4.7% ochloramine (H2NCI). One-hundred milliliters of this decrease per minute, and from the third addition, solution were pipetted into a 150-mL Fleaker and the rate was approximately 7.4% decrease per prepared as for the ammonia tests given in prior minute. Example 1 except no NaOH solution was added. There were no discernible differences between Example 6 the reference tubes and the test tubes in the ex- periments with the different water types and the #1 Research was conducted to investigate the re- SFB solution. This was also true of the tests with action of SFB solutions with tap water, conditioned the all purpose water conditioner instead of water. (aged) aquarium water, fresh synthetic sea water, In the tests with the all purpose water conditioner and conditioned (aged) synthetic sea water. This there were no discernible differences after 21 days. was done by adding 25-mL portions to equal portions of each water type and comparing to 25-mL Example 8 portions of the untreated water type mixed with 25 mL of deionized water in matched Nessler's tubes - Research was conducted to investigate the ef- (50 mL). fects of SFB solutions on seven different species of The same kind of comparison was made using freshwater fishes. The experimental design for a 25-ml sample of a commercially available all these tests were essentially the same throughout purpose water conditioner. except for the number and size of each species. Two species were captured by seining and the a full ten minutes) Just as in the prior tests, 5 other five species were purchased from a tropical angelfishes were added to each beaker. One beak- fish wholesaler. The species chosen represented er served as a control with no SFB solution added. "typical" families of freshwater aquarium fishes and The second and third beakers each received a 0.4 included cyprinids, poeciiiids, callichthyids, cich- mL dose of #1 SFB solution. The fishes were lids, characids, centrarchids, and ictalurids. All fish- observed during the first four hours and then at the es were quarantined for a minimum of 14 days 8th hour and at the 24th hour on termination of the before being used in any tests, and no species was test. The water was also sampled for total and used if any diseased or dying individuals were combined chlorine testing. Dead fish were removed observed among their population until no disease as found. The test procedure was carried out twice or deaths had been observed for at least 10 days. in its entirety. The test procedure for all species was the The municipal tap water utilized during the same. Three 4 liter beakers were filled with ap- testing was found to have a total chlorine content of proximately 3,000 mL of the water all from the 2.5 ppm and a combined chlorine content of 2.0 same source. Aeration was provided by a fine ppm. porosity airstone adjusted by valve so that the The experiment indicated that the #1 SFB solu- fishes were not required to "fight" a current in the tion protected the test fish, not only from death, but beaker. One of the three beakers was a control and also from the stressful effects of the new water. had no SFB solution added. A second beaker had Within 1 hour, the fish in the control beakers having 0.4 mL of the #1 SFB solution added, which repre- no SFB solution had assumed stress coloration sented a double "normal" dose of the active agent. characterized by darkening of their normal barred A third beaker had 4.0 mL added, which repre- pattern. Within 2 hours, 40% of the fish in the sented 10 times a "normal" dose. control beakers were judged to have lost the ability Five of each species of cyprinid (gold barbs, for normal swimming although they still responded Barbus semi-fasciolatus), poeciliid (red-velvet swor- to a sharp tap on the side of the beaker. At the dtails, Xiphophorus helleri), callichthyid (albino pep- conclusion of the tests, 50% of the fish (3 out of 5 pered catfish,Corvdoraspaleatus,cichlid (silver an- in test #1 and 2 out of 5 in test #2) in the control gelfish, Pteroohvllumemeeki), and characid (serpae beakers were dead. There were no mortalities in tetra, Hyphessobryconcallistusserpae) were used in the beakers to which SFB solutions had been ad- each beaker with one species per test. The ded. At I hour, the beakers were all tested for total cyprinids, characids, and cichlids were tested for chlorine. The control beakers showed no change in 24 and 48-hours with two separate tests per spe- chlorine content and the beakers containing SFB cies with different individual fishes used in each showed no chlorine presence. There was still resid- test. The other species were each tested for 24 ual chlorine in the control beakers at the conclusion hours. The centrarchids (iongear sunfish, of the tests after 24 hours. Leoomismeoalotis) and ictalurids (slender madtoms, Noturus exilis) were used at the rate of only Example 10 one fish per beaker and then only the 24-hour series were run for each species. An investigation was undertaken to determine No deaths occurred with any of the species the effect, if any, of overdose quantities of SFB on tested when SFB solutions were added to aged aquatic life in marine water. aquarium water. This was true for both the 24 and Thirty-six specimens of the pink-tipped anem- 48-hour tests. one, Condvlactus oiantea were distributed among four different 20-gal aquariums. The specific gravit- Example 9 ies of each tank were adjusted so that the first tank was 1.016, the second 1.020, the third 1.025, and Research was conducted to investigate the ef- the fourth 1.030. The anemones were allowed to fectiveness of SFB for protecting fishes against acclimate to their tanks for 10 days. Ten-milliliter toxic levels of chlorine and chloramines. portions of the #1 SFB solution were pipetted, by Using municipal tap water, I tested the effec- bulb, onto the opened oral discs of three anemones tiveness of the #1 SFB solution for protecting silver in each tank to observe the immediate reaction to angelfishes against the toxic effects of chlorine and the solution in excess and the long-term reaction to chloramines. The same three-beaker set-up was the solution in the tanks. Care was exercised to used as in the previous example, except that un- keep from touching the animal with the tip of the conditioned tap water was added to the beakers after the water was allowed to flow from the tap for pipette. After the #1 SFB solution was added, each The original aquarium census for these eleven tank was observed for the first hour and then at 8 aquariums was as follows: and 24 hours and then ad lib. for the next three days. Tank #1 one 6" male bluegill sunfish - I was unable to elicit any reaction from the (LeDomis macrochirus) anemones by pipetting the #1 SFB solution onto their oral discs. However, in separate tests with Tank #2 one 6" male longear sunfish deionized water substituted for #1 SFB solution, all of the anemones showed some reaction (6 of 6) Tank #3 one 5" female longear sunfish + but only 2 of the animals actually closed up in one 4" slender madtom response to the test. No deaths occurred among the population of test animals. Tank #4 fourteen 1" to 1-1/2" gold barbs

Example 11 Tank #5 five 1" to 1-1/2" gold barbs + one 1 " serpae tetra Research was conducted to investigate the long-term effectiveness of SFB for protecting fishes Tank #6 five 1-1/2" silver angels against toxic levels of chloramines, chlorine and ammonia and the longterm effect of overdose lev- Tank #12 two 3" slender madtoms els of SFB. Tank #13 one 7" green sunfish - (1) Four, 20-gallon "community" aquariums (LeDomiscvanellus) were set up with five silver angels, five gold barbs, six serpae tetras, four red-velvet Tank #14 ten 1 " to 1-1/2" gold barbs swordtails, and one albino pepperred catfish per tank. Each tank was given approximately Tank #16 nine 1-1/2" silver. angels a two-thirds water change daily, except on the weekends. One tank (#7) was dosed with Tank #18 six 1-1/2" silver angels 5 mL of a commercially available all-purpose The use, at first of 10 mL of the #1 SFB water conditioner after fresh tap water, with- solution, and subsequently 5 mL of #2 SFB solu- out any temperature adjustment, had been tion, resulted in exactly the same quantities of SFB added. A second tank (#8) was dosed with 5 being added to each of the test aquariums. All of mL of the same all-purpose water condi- the test tanks were fed daily, ad lib, except on tioner before the tap water was added. A weekends. All aquariums in these two tests were third tank (#10) was dosed with 10 mL of the filtered only with single under gravel filters. The #1 SFB solution for the first 13 days of the substrate in all test aquariums was 1/4" x 1/8" red test and then, for the remaining 17 days, flint filter gravel at a depth of 3". with 5 mL of #2 SFB solution before the tap In the water changing tests with all-purpose water was added. The fourth tank (#11) was water conditioner and the SFB solutions, one fish - dosed in the same manner as the third tank, (red-velvet swordtail) died in tank #11 and one fish first with 10 mL of the #1 SFB solution and died in tank #10 (red-velvet swordtail). In the all- then with 5 mL of #2 SFB solution after the purpose water conditioner tanks, one silver angel tap water was added. This test was con- died in tank #7. These deaths were not considered ducted for a total of 30 days for a total of 22 significant. The general health and appearance of water changes on each aquarium. all of the fishes were good. All of the fish were robust and ate with gusto when food was offered. (2) In eleven additional 20-gallon aquariums In the daily-dosed tanks which had no water various species and numbers were tested by changes or water additions, three (33-1/3%) angels adding 10.0 mL of the #1 SFB solution each died in tank #1. There were no other deaths. All of day, except weekends, for 23 days for a total the fishes ate with gusto and were robust and of 17 additions of #1 SFB solution and then healthy. All fishes exhibited normal behavioral pat- by adding 5 mL of #2 SFB solution each terns such as begging, displaying, schooling, and day, except weekends, for 17 days for a total normal coloration. of 13 additions of #2 SFB. During this 40- day period, no water was added or removed from the eleven test aquariums. Example 12 The ammonia SIE and meter were used in a direct reading mode so that the electrode responded only Research was conducted to investigate the ef- to the actual free ammonia in the solutions. For fect of pH on the reaction time of deamination in those tests in which the total ammonia was 1.00 synthetic sea water when using SFB solution. ppm, the meter was given a "set concentration" In these tests, an ammonia specific-ion elec- equal to 1.00 and 5.00 for the 5.00 ppm tests. The trode (SIE) and direct-reading meter were em- meter then tracked the actual, free ammonia in the ployed to track the change in the relative free solution and displayed a digital reading proportion- ammonia concentration over time. The physical ate to the changes which occurred over time as the parameters for these tests include specific gravity reaction progressed. equal to 1.020 as determined by refractometer; Results of the effect on the neutralization reac- temperature equal to 20° +1- 1 °C; and total am- tion of varying pH's in synthetic seawater and monia concentration equal to 1.00 ppm for one varying initial concentration of ammonia are pre- series of tests and 5.00 ppm for a second series of sented in Table 5 -11. This study reflects that the tests. The tests were conducted in covered beak- reaction favors an increase in pH level and also ers containing 1 liter of the test solution. The solu- favors higher initial concentrations of ammonia. tions were stirred continuously during the tests.

Thomas, via scheduled common air carrier, to Mi- Example 13 ami, Florida, thence to Kansas City, Missouri. The total shipping time was approximately 48 hours.No Research was conducted to determine the ef- untreated controls were used in this test. fectiveness of SFB solution to control losses of live - It is well known among aquaculturists that ma- marine animals due to high total free ammonia rine fishes and invertebrates suffer from and suc- levels as typically encountered in shipping contain- cumb to ammonia build-up in shipping bags con- ers. taining untreated water and that significant losses In these tests a variety of marine fishes and can be expected However, there were no deaths of invertebrates were collected in Nazareth Bay in any of the marine fishes and invertebrates shipped St. Thomas (U.S. Virgin Islands). These animals in #2 SFB treated-seawater The health and con- were packed in fresh seawater treated with the #2 dition of the fishes and invertebrates upon arrival SFB solution dosed at the rate of 4.93 mL/10 and subsequent removal to holding aquaria was gallons of seawater in sealed polyethylene bags. contrary to what would have occurred if no provi- The bags were approximately 1.5 liter in capacity. sion for ammonia control had been made. Each bag held approximately 500 mL of the treated seawater along with the animals and 1 liter of pure Example 14 oxygen. Each bag was placed inside another bag and sealed. The bags were placed in expanded A test was performed in which reduction in the styrene foam boxes inside corrugated cardboard measured ammonia concentration was measured boxes. Four such boxes containing a total of 65 over time using 0.117 mL of the KFB solution bags of live animals were then shipped from St. added to 500 mL of a hard water sample having a pH 8.0 at a temperature of 19.1 with a total ammonia concentration of 1.00 ppm. The results are shown in Table 12. A 31.7% reduction in the measured ammonia added to achieve a concentration of 2 ppm total concentration, at the end of 20 minutes, was dem- chlorine. In the second aquarium, a quantity of onstrated by the test. ammonium chloride solution was added to achieve a concentration of 1 ppm total ammonia. Into each Example 15 aquarium, 8.4 mL of the dry SFB mixture was measured by graduated cylinder and added without Research was conducted to determine the ef- mixing. Each aquarium was equipped with an air fectiveness of using a dry mixture form of SFB in diffuser to provide mixing and circulation of the place of SFB solutions to neutralize aqueous free water. chlorine (hypochlorites) and ammonia. The pH and temperature of each aquarium was A dry SFB mixture consisting of 58.995% so- noted at the beginning and end of the tests. The dium formaldehydebisulfite and 41.005% fine initial pH and final pH remained the same at 6.8. blending salt (sodium chloride) was used, The initial temperatures were 21.2° and the final volumetrically, at the same rate as for #2 SFB temperatures were 21.4° after 6 hours. No animals solution (i.e., 1 teaspoon/10. gallons) to treat two were'maintained in the aquariums during the tests. 20-gallon (75 liters) aquariums containing 17 gal- Samples of 100 mL were drawn from each lons (64 liters) each of aged freshwater. The aged aquarium at the start of the test and at time inter- water had been pooled from water taken from four vals of 1 hour, 2 hours, 3 hours and 6 hours for aquariums in which a mixed population of fishes determination of the concentrations of the target had been maintained for 8 months. In the first toxicants. aquarium, a quantity of commercial bleach was The results were consistent with and compara- respect to NH3, 12 times the stoichiometric amount ble to those obtained with #2 SFB solution Thus, with respect to NH2CI, 10 times the stoichiometric dry or solution formulations proved effective to amount with respect to NHCl2 or 12 times the neutralize the toxicants. stoichiometric amount with respect to HOCI and/or As indicated, this invention provides a one step OCI- ion. 1 method for timely neutralizing chloramines, chlorine and ammonia from saline and fresh waters for use 4. A process according to any preceding claim, in aquaculture. It is nontoxic to fishes, aquatic wherein the pH of the water is at least 6.0, e.g. invertebrates, marine and freshwater algaes, and to from 6.0 to 9.0. aquatic plants. It does not cloud the culture water or react with dissolved oxygen in the culture water. 5. A process according to any preceding claim, It functions effectively throughout the pH range of wherein the water is culture water substantially free 6.0 to 9.0 of waters in which most aquatic life is from non-target oxidising pollutants, e.g. perman- found. It can be combined with known water con- ganates, peroxides, dichromates and arylmethane ditioning chemicals and with known therapeutic dyes. agents used in aquaculture. From the foregoing it will be seen that this 6. A process according to any preceding claim, invention is one well adapted to attain all the ends wherein the bisulfite is added to the water in com- and objects hereinabove set forth, together with the bination with an inert material selected from other advantages which are obvious and which are diluents, carriers, excipients, lubricants, disinteg- inherent to the invention. rants and colourants. It will be understood that certain features and subcombinations are of utility and may be em- 7. A process according to claim 6, wherein any ployed without reference to other features and sub- diluents or carriers are selected from salt, sodium combinations. This is contemplated by and is with- sulfate, potassium chloride, starch, sugars, clays in the scope of the claims. and calcium sulfate, wherein any excipients are selected from cellulose gum, povidone and starches, wherein any lubricants .are selected from calcium stearate, magnesium stearate, paraffin wax and stearic acid, wherein any disintegrants are 1. A process for neutralising chloramines, chlorine selected from cross-linked povidone and sodium and ammonia in water, which comprises adding to bicarbonate/citric acid, and wherein any colourants the water a bisulfite selected from sodium formal- are selected from rose madder and acriflavin. dehydebisulfite and potassium formaldehydebisulfite, or one or more materials which react to form 8. A process according to any preceding claim, the bisutfiteinsitu. which comprises adding to the water two aqueous solutions of, respectively, formaldehyde and so- 2. A process according to claim I, wherein the dium bisulfite. water contains pollutant selected from NH3, NH2CI, NHC12, HOCI and OCI-ion, and the amount of the 9. A process according to claim 8, wherein the first bisulfite is at least stoichiometric with respect to aqueous solution contains at least 9% w/w formal- the pollutant. dehyde.

3. A process according to claim 2, wherein the 10. A process according to claim 8 or claim 9, minimum amount of the bisulfite which is added to wherein the second aqueous solution contains at the water is 4 times the stoichiometric amount with least 33% w/w sodium bisulfite.