Abstract: A urea treatment method in which hypobromite ions are generated by adding a chlorine-based oxidizer and a bromide salt to to-be-treated water containing urea so as to break down the urea in the to-be-treated water and obtain treated water, the method including: a) determining the free residual bromine concentration and the free residual chlorine concentration in the treated water; and b) controlling the added amount of the chlorine-based oxidizer and the bromide salt on the basis of the free residual bromine concentration and the free residual chlorine concentration. The device includes a bromide salt adding means, a chlorine-based oxidizer adding means, a urea decomposition tank, a residual chlorine meter, and a control device for controlling the added amount of the chlorine-based oxidizer by the chlorine-based oxidizer adding means on the basis of the method.

Abstract: A water treatment method that uses a reaction tank and involves repeatedly performing an operation cycle including: an inflow step for causing an inflow of waste water; a biological treatment step for subjecting the waste water to biological treatment using biological sludge; a sedimentation step for causing the biological sludge to settle; and a drainage step for draining biologically-treated water that has undergone the aforementioned biological treatment. The reaction tank is provided with an inflow port that is disposed at a position lower than an interface position of a biological sludge bed formed at the bottom of the reaction tank in the sedimentation step, and an inflow pipe that extends upward in the vertical direction from the inflow port. In the inflow step, the waste water is caused to gravitationally flow down in the inflow pipe so as to be fed into the biological sludge bed from the inflow port.

Abstract: Provided are a water treatment method and a water treatment device wherein in a biological treatment of ammonium nitrogen-containing water to be treated, the water to be treated can be treated stably at a high treatment speed even when the nitrogen concentration of the water to be treated is high. This water treatment device biologically treats ammonium nitrogen-containing water to be treated. The water treatment device (water treatment method) is provided with: a nitrification device (nitrification step) for oxidizing ammonium nitrogen to nitrite or nitrate nitrogen using nitrifying bacteria including autotrophic ammonia-oxidizing bacteria and nitrite-oxidizing bacteria contained in microbial activated sludge; and a nitrification rate control means which maintains a molybdenum compound in the nitrification device in such a manner as to control the molybdenum concentration of the water to be treated to 0.025 mg Mo/gN or more, and controls the nitrification rate for the sludge to 0.11 [kgN/(kgVSS·day)].

Abstract: Provided are: a water treatment method that includes at least a denitrification step for denitrifying water to be treated with a denitrifying bacterium in the presence of a hydrogen donor, wherein the denitrification activity of the denitrifying bacterium can be maintained at a high level and thus the treatment speed can be increased; and a water treatment apparatus. The water treatment method includes at least a denitrification step for passing water to be treated through a biological treatment tank and denitrifying the same with a heterotrophic denitrifying bacterium in the presence of a hydrogen donor, wherein: molybdenum is added to the water to be treated to give a concentration of 0.01-1.0 mgMo/gN; a carrier is added to the biological treatment tank; and the nitrogen load to the carrier is controlled to 1.6 kgN/(m3-carrier·d) or greater.

Abstract: Provided are a water treatment method and a water treatment device wherein in a biological treatment of ammonium nitrogen-containing water to be treated, the water to be treated can be treated stably at a high treatment speed even when the nitrogen concentration of the water to be treated is high. This water treatment device biologically treats ammonium nitrogen-containing water to be treated. The water treatment device (water treatment method) is provided with: a nitrification device (nitrification step) for oxidizing ammonium nitrogen to nitrite or nitrate nitrogen using nitrifying bacteria including autotrophic ammonia-oxidizing bacteria and nitrite-oxidizing bacteria contained in microbial activated sludge; and a nitrification rate control means which maintains a molybdenum compound in the nitrification device in such a manner as to control the molybdenum concentration of the water to be treated to 0.025 mg Mo/gN or more, and controls the nitrification rate for the sludge to 0.11 [kgN/(kgVSS·day)].

Abstract: A water treatment method that uses a reaction tank and involves repeatedly performing an operation cycle including: an inflow step for causing an inflow of waste water; a biological treatment step for subjecting the waste water to biological treatment using biological sludge; a sedimentation step for causing the biological sludge to settle; and a drainage step for draining biologically-treated water that has undergone the aforementioned biological treatment. The reaction tank is provided with an inflow port that is disposed at a position lower than an interface position of a biological sludge bed formed at the bottom of the reaction tank in the sedimentation step, and an inflow pipe that extends upward in the vertical direction from the inflow port. In the inflow step, the waste water is caused to gravitationally flow down in the inflow pipe so as to be fed into the biological sludge bed from the inflow port.

Abstract: Provided are a water treatment method and a water treatment device wherein in a biological treatment of ammonium nitrogen-containing water to be treated, the water to be treated can be treated stably at a high treatment speed even when the nitrogen concentration of the water to be treated is high. This water treatment device biologically treats ammonium nitrogen-containing water to be treated. The water treatment device (water treatment method) is provided with: a nitrification device (nitrification step) for oxidizing ammonium nitrogen to nitrite or nitrate nitrogen using nitrifying bacteria including autotrophic ammonia-oxidizing bacteria and nitrite-oxidizing bacteria contained in microbial activated sludge; and a nitrification rate control means which maintains a molybdenum compound in the nitrification device in such a manner as to control the molybdenum concentration of the water to be treated to 0.025 mg Mo/gN or more, and controls the nitrification rate for the sludge to 0.11 [kgN/(kgVSS·day)].

Abstract: Provided are: a water treatment method that includes at least a denitrification step for denitrifying water to be treated with a denitrifying bacterium in the presence of a hydrogen donor, wherein the denitrification activity of the denitrifying bacterium can be maintained at a high level and thus the treatment speed can be increased; and a water treatment apparatus. The water treatment method includes at least a denitrification step for passing water to be treated through a biological treatment tank and denitrifying the same with a heterotrophic denitrifying bacterium in the presence of a hydrogen donor, wherein: molybdenum is added to the water to be treated to give a concentration of 0.01-1.0 mgMo/gN; a carrier is added to the biological treatment tank; and the nitrogen load to the carrier is controlled to 1.6 kgN/(m3-carrier·d) or greater.

Abstract: Provided are a water treatment method and a water treatment device that can be introduced in a standard tank with an effective water depth of 5 m or less during treatment of water to be treated that contains organic matter and a nitrogen component, and that allow improvement in efficiency of removing nitrogen from the water to be treated and suppressing energy consumption for aeration while maintaining a high MLSS.

Abstract: Provided is a method for forming aerobic granules in which a semibatch reactor for forming granules is used, the method involving repeatedly carrying out an inflowing step for causing organic-matter-containing wastewater that includes organic matter to flow in, a biological treatment step for biologically treating substances to be treated in the organic-matter-containing drainage water by using microbial sludge, a settling step for allowing the microbial sludge to settle out, and a discharge step for discharging biologically treated water which has been biologically treated, wherein the reaction time is adjusted such that the value obtained by dividing the total cycle time by the reaction time and multiplying the resulting quotient by the ratio of the MLSS concentration to the BOD load charged into the semibatch reactor is within a range of 0.05 to 0.25 kgBOD/kgMLSS/d, and the sludge is drawn such that the sludge retention period is 5 to 25 days.

Abstract: A granule-forming method using a semi-batch reaction tank, wherein: operation cycles of a first operation cycle for performing a biological treatment step at a first sludge load and after the first operation cycle, a second operation cycle for performing the biological treatment step at a second sludge load are performed repeatedly; the first sludge load is set so that the soluble BOD concentration in the semi-batch reaction tank at the time of completion of the biological treatment step of the first operation cycle does not decrease to a threshold value or less; and the second sludge load is set so that the soluble BOD concentration in the semi-batch reaction tank at the time of completion of the biological treatment step of the second operation cycle is at or below the threshold value.

Abstract: A granule-forming method using a semi-batch reaction tank, wherein: operation cycles of a first operation cycle for performing a biological treatment step at a first sludge load and after the first operation cycle, a second operation cycle for performing the biological treatment step at a second sludge load are performed repeatedly; the first sludge load is set so that the soluble BOD concentration in the semi-batch reaction tank at the time of completion of the biological treatment step of the first operation cycle does not decrease to a threshold value or less; and the second sludge load is set so that the soluble BOD concentration in the semi-batch reaction tank at the time of completion of the biological treatment step of the second operation cycle is at or below the threshold value.

Abstract: Provided is a method for forming aerobic granules in which a semibatch reactor for forming granules is used, the method involving repeatedly carrying out an inflowing step for causing organic-matter-containing wastewater that includes organic matter to flow in, a biological treatment step for biologically treating substances to be treated in the organic-matter-containing drainage water by using microbial sludge, a settling step for allowing the microbial sludge to settle out, and a discharge step for discharging biologically treated water which has been biologically treated, wherein the reaction time is adjusted such that the value obtained by dividing the total cycle time by the reaction time and multiplying the resulting quotient by the ratio of the MLSS concentration to the BOD load charged into the semibatch reactor is within a range of 0.05 to 0.25 kgBOD/kgMLSS/d, and the sludge is drawn such that the sludge retention period is 5 to 25 days.

Abstract: Provided is a magnesium-air fuel cell in which a conductive state is achieved when a lid is fastened, and a nonconductive state is achieved when the lid is loosened, so that the power supply can be turned ON and OFF based on a fastening state of the lid. A lid includes a lower end portion that comes into contact with a main body at a time of fastening, an anode body inserted in the main body, and an electrode plate made of metal coupled to an end of the anode body. The electrode plate includes a first terminal at least positioned at the lower end portion. The main body includes a second terminal positioned on a surface that comes into contact with the lower end portion of the lid at the time of fastening the lid. Electrical conduction is achieved when the first terminal and the second terminal come into contact with each other.

Abstract: A magnesium-air fuel cell includes, in an inner portion, a pair of cathode accommodating portions each having at least one end opened. Cathode bodies are each disposed in a corresponding cathode accommodating portion, while having a part exposed to the inner portion. The part of each cathode body is separated from and faces an anode body. A power supply device using the fuel cell includes a supporting portion including a water supply port for the reaction liquid, a base portion incorporating the fuel cell, and a main body including a water supply pipe from the water supply port to the base portion. The water supply pipe is in communication with a water injection port in the fuel cell, and the water supply pipe incorporates a discharge pipe that extends from the supporting portion into the inner portion of the fuel cell and discharges reaction gas produced in the inner portion.

Abstract: Provided is a highly water repellent, air permeable, and liquid leakage resistant magnesium-air fuel cell that can quickly achieve a discharge reaction peak and can discharge a predetermined amount of current for a relatively long period of time. In a magnesium-air fuel cell, a cathode body includes: a first layer including a porous body formed by mixing a conductive carbon material and fluororesin; and a second layer including a porous body formed by mixing activated carbon and fluororesin, the second layer being joined to one surface of the first layer to be in contact with reaction liquid in the outer frame.

Abstract: Provided is a magnesium-air fuel cell in which a conductive state is achieved when a lid is fastened, and a nonconductive state is achieved when the lid is loosened, so that the power supply can be turned ON and OFF based on a fastening state of the lid. A lid includes a lower end portion that comes into contact with a main body at a time of fastening, an anode body inserted in the main body, and an electrode plate made of metal coupled to an end of the anode body. The electrode plate includes a first terminal at least positioned at the lower end portion. The main body includes a second terminal positioned on a surface that comes into contact with the lower end portion of the lid at the time of fastening the lid. Electrical conduction is achieved when the first terminal and the second terminal come into contact with each other.

Abstract: A magnesium-air fuel cell includes, in an inner portion, a pair of cathode accommodating portions each having at least one end opened. Cathode bodies are each disposed in a corresponding cathode accommodating portion, while having a part exposed to the inner portion. The part of each cathode body is separated from and faces an anode body. A power supply device using the fuel cell includes a supporting portion including a water supply port for the reaction liquid, a base portion incorporating the fuel cell, and a main body including a water supply pipe from the water supply port to the base portion. The water supply pipe is in communication with a water injection port in the fuel cell, and the water supply pipe incorporates a discharge pipe that extends from the supporting portion into the inner portion of the fuel cell and discharges reaction gas produced in the inner portion.

Abstract: Provided is a highly water repellent, air permeable, and liquid leakage resistant magnesium-air fuel cell that can quickly achieve a discharge reaction peak and can discharge a predetermined amount of current for a relatively long period of time. In a magnesium-air fuel cell, a cathode body includes: a first layer including a porous body formed by mixing a conductive carbon material and fluororesin; and a second layer including a porous body formed by mixing activated carbon and fluororesin, the second layer being joined to one surface of the first layer to be in contact with reaction liquid in the outer frame.

Abstract: A liquid leakage detection system requiring no power supply from an outer source and configured to be relatively simple and moderate in price. A liquid leakage detection system (10) including an infusion tube (11), a syringe needle (12) coupled to the infusion tube (11), an absorbent element (16) adapted to be placed in the vicinity of a point (12a) of the syringe needle (12) to be pricked through a patient skin and a sensor unit (14) located on an upper side or within the absorbent element (16).