Abstract: Provided is a method for producing a one-liquid stabilized hypobromous acid composition which contains substantially no bromate ions, has excellent sterilization performance, exhibits almost no corrosiveness relative to metals, and displays excellent storage stability. This method for producing the stabilized hypobromous acid composition includes a step in which a reaction is induced by adding, under an inert gas atmosphere, bromine to a mixed solution including water, an alkali hydroxide, and sulfamic acid, wherein the proportion of bromine added is not more than 25 wt % relative to the total weight of the composition.

Abstract: Provided is a sterilization method for a water system, the sterilization method being capable of suppressing the production amount of a nitrosamine compound while exhibiting a sufficient sterilization effect in precursor-containing water that contains a nitrosamine compound precursor. In the sterilization method for a water system, a stabilizing composition containing a bromine-based oxidizing agent or a chlorine-based oxidizing agent and a sulfamic acid compound is added to the precursor-containing water that contains the nitrosamine compound precursor.

Abstract: Provided is a method for producing a one-liquid stabilized hypobromous acid composition which contains substantially no bromate ions, has excellent sterilization performance, exhibits almost no corrosiveness relative to metals, and displays excellent storage stability. This method for producing the stabilized hypobromous acid composition includes a step in which a reaction is induced by adding, under an inert gas atmosphere, bromine to a mixed solution including water, an alkali hydroxide, and sulfamic acid, wherein the proportion of bromine added is not more than 25 wt % relative to the total weight of the composition.

Abstract: Provided is a method for producing a one-liquid stabilized hypobromous acid composition which contains substantially no bromate ions, has excellent sterilization performance, exhibits almost no corrosiveness relative to metals, and displays excellent storage stability. This method for producing the stabilized hypobromous acid composition includes a step in which a reaction is induced by adding, under an inert gas atmosphere, bromine to a mixed solution including water, an alkali hydroxide, and sulfamic acid, wherein the proportion of bromine added is not more than 25 wt % relative to the total weight of the composition.

Abstract: This filtration treatment system is provided with a membrane filtration device as a prefiltration treatment device for removing insoluble components from the water to be treated containing organic substance, a reverse osmosis membrane treatment device for subjecting the prefiltration-treated water to reverse osmosis membrane treatment, and a chemical agent supply pipe for supplying a chemical agent into the membrane filtration device, wherein the chemical agent contains a sulfamic acid compound, and a bromine-based oxidizing agent or the reaction product of a bromine compound with a chlorine-based oxidizing agent, or, contains the reaction product of a sulfamic acid compound with a bromine-based oxidizing agent or with the reaction product of a bromine compound with a chlorine-based oxidizing agent.

Abstract: This filtration treatment system is provided with a membrane filtration device as a prefiltration treatment device for removing insoluble components from the water to be treated containing organic substance, a reverse osmosis membrane treatment device for subjecting the prefiltration-treated water to reverse osmosis membrane treatment, and a chemical agent supply pipe for supplying a chemical agent into the membrane filtration device, wherein the chemical agent contains a sulfamic acid compound, and a bromine-based oxidizing agent or the reaction product of a bromine compound with a chlorine-based oxidizing agent, or, contains the reaction product of a sulfamic acid compound with a bromine-based oxidizing agent or with the reaction product of a bromine compound with a chlorine-based oxidizing agent.

Abstract: Provided is a method for producing a one-liquid stabilized hypobromous acid composition which contains substantially no bromate ions, has excellent sterilization performance, exhibits almost no corrosiveness relative to metals, and displays excellent storage stability. This method for producing the stabilized hypobromous acid composition includes a step in which a reaction is induced by adding, under an inert gas atmosphere, bromine to a mixed solution including water, an alkali hydroxide, and sulfamic acid, wherein the proportion of bromine added is not more than 25 wt % relative to the total weight of the composition.

Abstract: A water-soluble lithium salt is added as a tracer substance along with a water treatment chemical to water to be treated. The concentration of lithium ions is electrochemically or optically measured using a lithium ion sensitive substance, so as to perform concentration control of the water treatment chemical added to water to be treated. An ion selective electrode, ion selective field effect transistor, or ion optode may be employed to perform the electrochemical or optical measurement using a lithium ion sensitive substance.

Abstract: A water-soluble lithium salt is added as a tracer substance along with a water treatment chemical to water to be treated. The concentration of lithium ions is electrochemically or optically measured using a lithium ion sensitive substance, so as to perform concentration control of the water treatment chemical added to water to be treated. An ion selective electrode, ion selective field effect transistor, or ion optode may be employed to perform the electrochemical or optical measurement using a lithium ion sensitive substance.