Abstract: The filtration system of the present invention comprises first and second filtration tanks. The first filtration tank has a first floating filter media layer, a first upper screen with a first aperture ratio, a first inlet, a first backwash water supply source, and a first backwash water outlet means. The second filtration tank has a second floating filter media layer, a second upper screen with a second aperture ratio, a second inlet, an inflow blocking mechanism capable of blocking inflow of water to be treated through the second inlet, a second backwash water supply source, and a second backwash water outlet means. The first aperture ratio is smaller than the second aperture ratio.

Abstract: A sludge filtration apparatus has a sludge tank configured to store sludge and at least one filter assembly. The filter assembly includes a filtration membrane for filtering the sludge and a pipe insertable in the filtration membrane to supply air to a secondary side of the filtration membrane for dislodging the sludge from the filtration membrane. The pipe has a plurality of holes for discharging gas, namely air, to an area in which the filtration membrane inclines downwardly with the secondary side thereof. The sludge filtration apparatus can prevent thickened sludge from remaining in an upper portion of the filter assembly.

Abstract: When a separation membrane (3) is washed with a chemical solution that is a sodium hypochlorite solution, which has a high concentration, diluted with membrane treated water stored in a chemical solution tank (6), an ammonic nitrogen concentration in membrane-treated water is monitored with a monitoring device (9), and a control device (8) controls a chemical solution dosing pump (7) using the concentration measured by the device (9) to adjust a dilution rate. Thereby, even when water quality of membrane-treated water varies, a sodium hypochlorite concentration in backwashing water can be retained constant, and fluctuation in the chemical washing effect can be prevented.

Abstract: Provided are a method and an apparatus that enable rapid and automatic determination of the coagulant injection rate in a process of water treatment through coagulation and sedimentation. Using a coagulation analyzer comprising sample tanks 1A to 1D each for keeping a predetermined amount of raw water, a water supply pump 7, water supply/discharge valves 4, 6 for raw water and washing water, mixers 3A to 3D, a coagulant injection unit 21, and a detector 30 for determining the particle size and the particle number of flocs, the time within which the coagulant 20 injected into the sample tanks is dispersed by mixing and the particles begin to agglomerate (agglomeration start time) is determined, and based on the thus-determined agglomeration start time, the coagulant injection rate is determined, or the amount of the coagulant to be injected is controlled.

Abstract: Provided is a biological nitrogen removal method which includes, causing to flow a support having, on the surface portion thereof, a two-layered microbial film which holes, in the outer layer, nitrite type nitrifying bacteria or aerobic bacteria and nitrite type nitrifying bacteria as a dominant species and, in the inner layer, anaerobic ammonia oxidizing bacteria as a dominant species while being surrounded with the nitrite type nitrifying bacteria; and thereby carrying out denitrification of the water to be treated by making use of the anaerobic ammonia oxidation reaction. In the biological nitrogen removal method, a feed rate of the support (total surface area of the support per unit capacity of the reaction tank) is adjusted so that an amount of nitrous acid produced by the nitrite type nitrification reaction through the action of the nitrite type nitrifying bacteria reaches a level to inhibit a nitrate type nitrification reaction.

Abstract: The invention provides a N2O removal method for a waste gas which is capable of stably decomposing and removing N2O even if the steam concentration in the waste gas is fluctuated. N2O is reduced and removed by bringing the waste gas containing N2O into contact with a reducing agent in the presence of a N2O decomposition catalyst. The temperature of the waste gas to be brought into contact with the N2O decomposition catalyst or the addition amount of the reducing agent is controlled in accordance with the steam concentration in the waste gas in a prior stage of the N2O decomposition catalyst. Therefore, the N2O decomposition efficiency is prevented from being decreased. An iron-zeolite based catalyst may be used as the N2O decomposition catalyst and methane, propane, ammonia, etc. may be used as the reducing agent.

Abstract: The process includes operation as follows: putting ozone generated by an ozone generator into raw water, in a normal mode, to subject the raw water to ozone treatment; injecting a flocculant into the raw water before or after the ozone treatment; filtering the raw water by a separation membrane after the ozone treatment and the injection of the flocculant; and intermittently setting cleaning mode to put a larger quantity of cleaning ozone than that in the normal mode into the raw water so as to intermittently increase the concentration of dissolved ozone, thereby cleaning the filtration membrane.

Abstract: An object of the present invention is to provide a filtering and condensing apparatus of the suction type which is capable of improving the filtering efficiency by securing the filtering area, while at the same time keeping an integrity of the filtering cloth. A filtering and condensing apparatus of a suction type comprises a sludge tank for containing sludge to be filtered and condensed, and a plurality of filtering plates aligned with each other so as to be disposed to be adjacent to each other in the sludge tank. Each plane portion of the filtering plates extends in the vertical direction.

Abstract: An object of the present invention is to provide a filtering and condensing apparatus of the suction type which is capable of securing the filtering performance without deteriorating the filtering efficiency. A filtering and condensing apparatus of a suction type comprises a sludge tank for containing sludge to be filtered and condensed, and a filtering plate disposed to be in the sludge tank and extending in the vertical direction of the sludge tank. The filtering plate includes vertical extending convex and concave portions on its surface, and a filtering cloth in a bag form to house the supporting plate, whereby a filtering chamber is formed between the filtering cloth and the filtering plate and a main flow passage for the filtrate which vertically extends is formed between the inner surface of the filtering cloth and the concave portion of the supporting plate.

Abstract: Provided is a biological nitrogen removal method which includes, causing to flow a support having, on the surface portion thereof, a two-layered microbial film which holes, in the outer layer, nitrite type nitrifying bacteria or aerobic bacteria and nitrite type nitrifying bacteria as a dominant species and, in the inner layer, anaerobic ammonia oxidizing bacteria as a dominant species while being surrounded with the nitrite type nitrifying bacteria; and thereby carrying out denitrification of the water to be treated by making use of the anaerobic ammonia oxidation reaction. In the biological nitrogen removal method, a feed rate of the support (total surface area of the support per unit capacity of the reaction tank) is adjusted so that an amount of nitrous acid produced by the nitrite type nitrification reaction through the action of the nitrite type nitrifying bacteria reaches a level to inhibit a nitrate type nitrification reaction.

Abstract: An object of the present invention is, in a case where a filtering and condensing apparatus of a suction type is upsized, to provide such an apparatus which is capable of securing an integrity of a filtering cloth, while at the same time of preventing a lower portion of the filtering cloth from being slackened by maintaining the vertical tension force applied to the filtering cloth to be substantially constant. A filtering and condensing apparatus of a suction type comprises a sludge tank for containing sludge to be filtered and condensed, and a plurality of filtering plates aligned with each other so as to be disposed to be adjacent to each other in the sludge tank. Each plane portion of the filtering plate extends in the vertical direction. Each of the filtering plates includes a supporting plate in the form of a net, and a filtering cloth in a bag form so as to be integrally sewed on the supporting plate and to house the supporting plate, whereby a filtering chamber is formed inside the filtering cloth.

Abstract: Provided are a method and an apparatus that enable rapid and automatic determination of the coagulant injection rate in a process of water treatment through coagulation and sedimentation. Using a coagulation analyzer comprising sample tanks 1A to 1D each for keeping a predetermined amount of raw water, a water supply pump 7, water supply/discharge valves 4, 6 for raw water and washing water, mixers 3A to 3D, a coagulant injection unit 21, and a detector 30 for determining the particle size and the particle number of flocs, the time within which the coagulant 20 injected into the sample tanks is dispersed by mixing and the particles begin to agglomerate (agglomeration start time) is determined, and based on the thus-determined agglomeration start time, the coagulant injection rate is determined, or the amount of the coagulant to be injected is controlled.

Abstract: The present invention provides a technique for producing acetone in a high yield from hydrated ethanol derived from biomass, without requiring a large amount of energy. Hydrated ethanol derived from biomass is heated to a reaction temperature of 400° C. or higher in the presence of a Zr—Fe catalyst, thereby producing acetone. The reaction temperature is preferably from 450 to 550° C., and the Zr—Fe catalyst preferably contains 5 to 10% by mass of Zr. The present invention allows purification of hydrated acetone without requiring purification of the hydrated ethanol.

Abstract: The present invention provides an upward-flow manganese contact column for feeding raw water to a manganese catalyst-packed layer through a plurality of dispersion nozzles provided at the upper surface of a chamber by forming the chamber for allowing raw water to flow in at the bottom of a column body into which a granular manganese catalyst is packed. Each dispersion nozzle has an umbrella portion above a perpendicular nozzle body, and the umbrella portion is configured so that the lower end of the umbrella portion is elongated below the upper end of the nozzle body. Raw water is supplied to the entire manganese catalyst-packed layer from the lower end of the umbrella portion of each dispersion nozzle. It is capable, of exhibiting stable treatment ability for a long time by suppressing particles of the manganese catalyst from being worn by collisions of the particles.

Abstract: The invention provides a side stream type membrane bioreactor process which does not cause an excessive fall in the MLSS concentration in a bioreactor, does not require any additional effluent treatment facility for discharging backwash effluent, and can further ensure the stability of the membrane filtration performance of a separation membrane. According to the invention, in a side stream type membrane bioreactor process, a backwash effluent containing foulants that are generated by backwashing a separation membrane is collected in a backwash effluent tank, and subjected to ozone treatment, and the resultant is returned to a bioreactor. By this ozone treatment, the foulants close to the membrane pore size of the separation membrane are made fine or are made into a state be easily taken into activated sludge flocs. Therefore, even when the treated effluent is returned to the bioreactor, the membrane filtration performance of the separation membrane is not deteriorated.

Abstract: The present invention provides a technique for producing acetone in a high yield from hydrated ethanol derived from biomass, without requiring a large amount of energy. Hydrated ethanol derived from biomass is heated to a reaction temperature of 400° C. or higher in the presence of a Zr—Fe catalyst, thereby producing acetone. The reaction temperature is preferably from 450 to 550° C., and the Zr—Fe catalyst preferably contains 5 to 10% by mass of Zr. The present invention allows purification of hydrated acetone without requiring purification of the hydrated ethanol.

Abstract: There is provided a process capable of inexpensively producing reclaimed water having excellent quality from wastewater without using a large amount of ozone. The process for producing reclaimed water comprises: bringing ozone into contact with raw water such as treated sewage using an ozone contact column 2 or the like to enhance coagulability of a solid matter contained in the raw water; injecting a coagulant into the raw water using a coagulant-injecting pump 6 to coagulate the solid matter; and membrane-filtering the coagulated solid matter through a separation membrane 8. A residual ozone concentration in the raw water before a separation membrane is measured by a dissolved-ozone meter 5. When deterioration of quality of the raw water results in an ozone demand exceeding capacity of an ozone generator and in the residual ozone concentration lower than a given value, an amount of the coagulant to be injected is increased.

Abstract: The invention provides a N2O removal method for a waste gas which is capable of stably decomposing and removing N2O even if the steam concentration in the waste gas is fluctuated. N2O is reduced and removed by bringing the waste gas containing N2O into contact with a reducing agent in the presence of a N2O decomposition catalyst 9. The temperature of the waste gas to be brought into contact with the N2O decomposition catalyst 9 or the addition amount of the reducing agent is controlled in accordance with the steam concentration in the waste gas in a prior stage of the N2O decomposition catalyst 9. Therefore, the N2O decomposition efficiency is prevented from being decreased. An iron-zeolite based catalyst may be used as the N2O decomposition catalyst and methane, propane, ammonia, etc. may be used as the reducing agent.

Abstract: The invention provides a side stream type membrane bioreactor process which does not cause an excessive fall in the MLSS concentration in a bioreactor, does not require any additional effluent treatment facility for discharging backwash effluent, and can further ensure the stability of the membrane filtration performance of a separation membrane. According to the invention, in a side stream type membrane bioreactor process, a backwash effluent containing foulants that are generated by backwashing a separation membrane is collected in a backwash effluent tank, and subjected to ozone treatment, and the resultant is returned to a bioreactor. By this ozone treatment, the foulants close to the membrane pore size of the separation membrane are made fine or are made into a state be easily taken into activated sludge flocs. Therefore, even when the treated effluent is returned to the bioreactor, the membrane filtration performance of the separation membrane is not deteriorated.

Abstract: An inside of an incinerator body into which sludge is fed is divided into a lower portion, a portion above the lower portion, and a top portion in a height direction. The lower portion serves as a pyrolysis zone for supplying fluidizing air having an air ratio of 1.1 or less together with fuel to thermally decompose the sludge while fluidizing the sludge. The portion above the lower portion serves as an over bed combustion zone for supplying only combustion air having an air ratio of 0.1 to 0.3 to form a local high temperature place to decompose N2O. The top portion serves as a perfect combustion zone for perfectly combusting unburned contents. The quantity of N2O generated during sludge incineration can be drastically reduced while maintaining the use quantity of auxiliary fuel at the same level as that of a conventional incineration method.