Abstract: A water heater, which allows efficient deposition of a scale component dissolved in water so as to reduce adhesion of the scale to a heat-transfer channel. The water heater includes: scale deposition device including a tank, an anode and a cathode provided in the tank so as to be opposed to each other, and a first power supply for applying a voltage between the anode and the cathode, the scale deposition device depositing a scale component dissolved in water retained in the tank; a heat-transfer channel provided at downstream of the scale deposition device, for guiding the water; and a heat source for heating the water by heat exchange in the heat-transfer channel, in which the scale deposition device includes oxygen-gas supplying/dissolving means for supplying an oxygen gas to a water feed pipe for feeding the water to the tank and dissolving the oxygen gas in the water.

Abstract: A water heater in which by applying pulsation of a liquid to be heated which circulates between a tank and a heat exchanger, scale that has been deposited on the inner wall (heat-transfer surface) of a to-be-heated liquid flow channel in a heat exchanger is detached, and the number of times of circulation of the liquid to be heated which circulates between the tank and the heat exchanger is controlled to be three times or less. The number of times of circulation is determined, based on the entire volume of the to-be-heated liquid stored in the tank, a boiling time to be taken for the entire volume of the to-be-heated liquid in the tank to reach a predetermined temperature, and the flow rate of the to-be-heated liquid which passes through the to-be-heated liquid flow channel.

Abstract: In an aeration apparatus according to the present invention, water-repellent treatment is applied at least to one of an opening and vicinity thereof of a slit 12 formed in a diffuser membrane of an aeration nozzle, thereby providing a water-repellent layer 150, so that the inflow of seawater into the slit 12 is prevented and precipitation of calcium sulfate or the like in the slit is suppressed and avoided. As a material for forming the water-repellent layer 150, for example, a talc coating layer using talc, a fluorine coating layer coated with a fluorine resin, silicone coating layer coated with a silicone resin, and a wax coating layer coated with wax can be mentioned.

Abstract: A first slit 12A formed in a diffuser membrane of aeration diffusers of an aeration apparatus according to the present invention includes a linear reference slit 12a and a branched slit 12b crossing the linear reference slit 12a at a center thereof, and an opening shape of the first slit 12A is deformed due to pressure of air (an amount of air) to be supplied. Therefore, because an opening amount at a crossing 12c of the linear reference slit 12a and the branched slits 12b increases by temporarily increasing the amount of air, elimination of precipitates is facilitated, differently from conventional cases having only linear slits.

Abstract: An aeration apparatus is immersed in diluted used seawater (not shown) which is water to be treated and generates fine air bubbles in the diluted used seawater. The aeration apparatus includes: an air supply line L5 for supplying air 122 through blowers 121A to 121D serving as discharge unit; aeration nozzles 123, each of which includes a diffuser membrane 11 having slits and to which air containing moisture is supplied; and a control unit for performing control to temporarily stop supply of the air 122 at predetermined intervals.

Abstract: Provided is a water heater, which allows efficient deposition of a scale component dissolved in water so as to reduce adhesion of the scale to a heat-transfer channel. The water heater includes: scale deposition means including a tank, an anode and a cathode provided in the tank so as to be opposed to each other, and a first power supply for applying a voltage between the anode and the cathode, the scale deposition means depositing a scale component dissolved in water retained in the tank; a heat-transfer channel provided at downstream of the scale deposition means, for guiding the water; and a heat source for heating the water by heat exchange in the heat-transfer channel, in which the scale deposition means includes oxygen-gas supplying/dissolving means for supplying an oxygen gas to a water feed pipe for feeding the water to the tank and dissolving the oxygen gas in the water.

Abstract: A water treatment method sufficiently decomposes low-degradable organic substances while suppressing production of bromate ions and consumption of hydrogen peroxide. A water treatment method for purifying water using radicals includes injecting an electron-donating substance selected from the group consisting of saccharides, amino acids, lipids, humic acid, and mixtures thereof into water. The radicals are preferably produced using ozone and hydrogen peroxide in combination. Further, the electron-donating substance is preferably injected into the water in a concentration of 0.1 ?mol/L to 30 ?mol/L.

Abstract: In a process of eluting phosphorus from sludge into a liquid phase and recovering the phosphorus efficiently, cell walls of microorganisms in the sludge are ruptured by a process selected from crushing sludge (for example, treating with an ultrasonic wave homogenizer), treating with ozone, and treating with heat. Then the liquid phase is treated with alkali, thereby eluting the phosphorus into a liquid phase efficiently in a short time. By coagulating and precipitating, the phosphorus eluted into the liquid phase is recovered.

Abstract: A water treatment apparatus dissolving an oxidizer in wastewater at a fast speed and at a high efficiency to decompose substances at a high decomposition rate. The apparatus includes an ultraviolet radiation part having an elongated tubular configuration, and receiving an axially extending ultraviolet radiation unit with a space between an inner peripheral surface of the ultraviolet radiation unit and the ultraviolet radiation unit to pass wastewater; and an oxidizer mixing part disposed adjacent to and upstream of the ultraviolet radiation part for mixing an oxidizer with the wastewater. The ultraviolet radiation unit irradiates the wastewater with ultraviolet light to decompose the substances to be treated in the wastewater.

Abstract: A process for treating organic wastewater which comprises treating organic wastewater with ozone and successively with alkali and introducing said alkali treated organic wastewater into an anaerobic digestion tank for anaerobic digestion. Instead of the ozone and successive alkali treatments, ozone treatment in the presence of hydrogen peroxide or ozone treatment under UV radiation is applicable. Prior to introduction into the anaerobic digestion tank, the treated wastewater may be separated into solids and phosphorus is preferably recovered from the solution. Solubilization of solids in the organic wastewater and transformation of organic substances into methane are greatly enhanced and sludge to be disposed is greatly reduced. Moreover, phosphorus is efficiently eluted out and recovered from solids in the organic wastewater.

Abstract: The object of the present invention is to elute phosphorus out of sludge into a liquid phase and then recover phosphorus efficiently in a shorter time. The process of the present invention comprises one process selected from crushing sludge (for example, treating with an ultrasonic wave homogenizer), treating with ozone and treating with heat, and then alkalizing a liquid phase by treating with alkali (adding alkali), crushing cell walls of microorganisms in sludge, thereby eluting phosphorus into a liquid phase efficiently in a shorter time, and furthermore coagulating and precipitating phosphorus eluted into a liquid phase and recovering the resultant phosphorus.

Abstract: A water treatment apparatus dissolving an oxidizer in wastewater at a fast speed and at a high efficiency to decompose substances at a high decomposition rate. The apparatus includes an ultraviolet radiation part having an elongated tubular configuration, and receiving an axially extending ultraviolet radiation unit with a space between an inner peripheral surface of the ultraviolet radiation unit and the ultraviolet radiation unit to pass wastewater; and an oxidizer mixing part disposed adjacent to and upstream of the ultraviolet radiation part for mixing an oxidizer with the wastewater. The ultraviolet radiation unit irradiates the wastewater with ultraviolet light to decompose the substances to be treated in the wastewater.

Abstract: A process for treating organic wastewater which comprises treating organic wastewater with ozone and successively with alkali and introducing said alkali treated organic wastewater into an anaerobic digestion tank for anaerobic digestion. Instead of the ozone and successive alkali treatments, ozone treatment in the presence of hydrogen peroxide or ozone treatment under UV radiation is applicable. Prior to introduction into the anaerobic digestion tank, the treated wastewater may be separated into solids and phosphorus is preferably recovered from the solution. Solubilization of solids in the organic wastewater and transformation of organic substances into methane are greatly enhanced and sludge to be disposed is greatly reduced. Moreover, phosphorus is efficiently eluted out and recovered from solids in the organic wastewater.

Abstract: During a waste water treatment process such as an activated-sludge process using microorganisms, the present invention ozonizes a microorganism-mixed liquid. It reduces the amount of microorganisms remaining, prevents a microorganism floc from sedimenting inappropriately, and recovers appropriate sedimentation while maintaining treatment performance. A waste water ozonization apparatus according to an embodiment of the present invention can include a sludge drawing pump which draws a microorganism-mixed liquid from an aeration vessel; an ozonizer for generating ozone gas which reacts with the microorganism-mixed liquid; an ozonization vessel which injects the ozone gas generated by the ozonizer into the drawn microorganism-mixed liquid; an ozonized-sludge channel that returns the ozonized microorganism-mixed liquid to the aeration vessel; and a control section for intermittently performing an ozonization operation.

Abstract: Hydrogen peroxide in a hydrogen peroxide reservoir is supplied to an effluent. Ozone gas generated in an ozone generating apparatus is delivered through branched piping to two ozone supplying points and is supplied to the effluent. The ozone and the supplied hydrogen peroxide react to generate hydroxyl radicals. The hydroxyl radicals react with the materials in the effluent to decompose and remove them.