Abstract: The present invention relates to zirconium silicate compositions having a lead content that is below 0.6 ppm and methods of manufacturing zirconium silicate at reactor volumes exceeding 200-L with a lead content below 1.1 ppm. The lead content of the zirconium silicate of this invention are within the levels that are considered acceptable for extended use given the dose requirements for zirconium silicate.

Abstract: A sewage treatment apparatus is provided for reducing nitrogen content in sewage fluid (e.g., after primary treatment). The apparatus uses vegetation to process the sewage fluid and reduce ammonia and organic nitrogen in the processed sewage fluid by uptake of the ammonia and organic nitrogen into the vegetation and by converting the residual ammonia and organic nitrogen into nitrites and nitrates. The apparatus also uses a feedback loop to combine the processed sewage fluid and the raw sewage fluid, such that nitrites and nitrates in the processed sewage fluid are reduced by interacting with carbonaceous waste in the raw sewage fluid.

Abstract: A method and a system for recovering nitrogen, and optionally phosphorus and/or potassium, from a liquid waste stream, such as a stream of urine or manure, or human urine is described. The method comprises passing the waste stream through a multi-compartment electrodialysis bipolar membrane (EDBM) system.

Abstract: Provided are an anaerobic ammoxidation synergistic nitrogen removal process device of municipal sewage main and side streams and an application method thereof, comprising a municipal sewage raw water tank (1), a biological reaction pool (2), a secondary sedimentation pool (3), a sludge digestion solution raw water tank (4) and a sludge digestion solution AOB strengthening pool (5); wherein, the municipal sewage raw water tank (1) is connected with a water inlet valve (2.2) of the biological reaction pool (2) through a water inlet pump (2.1) of the biological reaction pool (2); the biological reaction pool (2) is connected with the secondary sedimentation pool (3) through a secondary sedimentation pool connection pipe (3.3); the sludge digestion solution raw water tank (4) is connected with a water outlet valve (4.1) of the sludge digestion solution raw water tank (4) through a water inlet pump (4.

Abstract: The present invention describes a method of optimizing CO2 concentration to increase the specific growth rate of Anammox bacteria and methanogens in wastewater and sludge treatment, as well as novel systems and methods of treating wastewater and sludge. The specific growth rate or doubling time of the Anammox bacteria and methanogens were determined to be sensitive to dissolved CO2 concentration. Optimizing dissolved CO2 concentration increases the specific growth rate of the Anammox bacteria, which may be used as an alternative biological nitrogen removal process for the treatment of domestic wastewater. In the method and system of treating sludge, the CO2 stripper returns biogas with low CO2 concentration to the headspace of an anaerobic digester in order to lower the headspace CO2 concentration and therefore, the soluble CO2 concentration. The lower soluble CO2 concentration increases the specific growth rate of the methanogens for a more efficient anaerobic digestion process.

Abstract: A system of treating high nitrogen content waste water is disclosed, where the system includes a precipitation and conditioning subsystem, an ammonia stripper subsystem, and a denitrification subsystem. The system is adapted to reduce nitrogen contamination to level below about 10 ppm and in certain embodiments below 3 ppm.

Abstract: Disclosed are apparatus and method for alternative aeration-effluent wastewater treatment using a ceramic membrane, which allows the biological treatment to be performed sufficiently in an intermittent aeration tank by combining an anaerobic tank with a plurality of intermittent aeration tanks and selectively changing an inflow path of influent water according to an operation status of the intermittent aeration tanks. The present disclosure is directed to providing an apparatus and method for alternative aeration-effluent wastewater treatment, which allows the aeration and treated water to continuously discharge through two intermittent aeration tanks by independently forming an air injection line and a treated water discharge line at a ceramic membrane provided in each intermittent aeration tank.

Abstract: Novel methods and systems for efficient and economic treatment of wastewater, and other fluidized and solid organic wastes, comprise heating the aerobic digestion process with waste heat given off by the generation of power fueled by the biogas by-product of a co-located anaerobic digestion process. Other power generation processes may be utilized for supplying supplemental waste heat.

Abstract: The invention relates to a method for controlling oxygen supply in a tank (2) for biologically treating wastewater by alternating aeration including consecutive cycles, wherein each cycle comprises a first aeration phase and a second anoxic phase for reducing nitrites and nitrates formed during the preceding aeration phase, the tank is provided with sensors for measuring ammonia nitrogen (4b) and for measuring nitrate (4c) and optionally for measuring oxygen (4a) that is dissolved in the tank liquor or in the liquor thereof exiting the tank, a method according to which the oxygen supply is controlled in the aeration phase when the reduction speed of the nitrate measurement is less than a bottom threshold and the cutoff of the oxygen supply is also controlled in the aeration phase when at least one of the following triggering events occurs: the reduction speed in the measurement of ammonia nitrogen becomes lower than a bottom threshold; the total sum of ammonia nitrogen and nitrate measurements becomes higher

Abstract: A method and system of treating wastewater is disclosed. The treatment system has a nitrification-denitrification system comprising a sorption system, a biofilm system, and an anaerobic digester that digests or converts at least a portion of the solids or sludge from the sorption system and biofilm system.

Abstract: A hybrid method and system of treating wastewater with reduced energy usage is disclosed. The treatment system has a sorption system, an anaerobic digester that digests or converts at least a portion of the solids or sludge from the sorption system, and an aerobic treatment tank that partially reduces oxygen demand of a portion of the sludge from the sorption tank.

Abstract: An improved upward flow constructed wetland cell for treatment of water contaminated with chlorinated aliphatics is disclosed. The improvements include adding ammonia-oxidizing microorganisms to the methane-oxidizing microorganisms already present in an oxygenated root zone and adding improved pore-water sample chambers for measuring the performance of the constructed wetland cell.

Abstract: A filtration device for an aquarium comprising a filtering chamber for receiving water and a filter medium therein wherein said filter medium comprises fibers having a diameter from 0.1 nm to 3000 nm and an aspect ratio of length to diameter of 5:1 to 10,000 to 1 wherein said fibers provide for colonization of nitrosomonas bacterium and/or nitrobacteria.

Abstract: Waste-treatment processes are enhanced through generation and introduction of specific biological populations customized to perform or favor specific tasks either during the main process, for the formation or precipitation of certain biological nutrients, or to accomplish solids formation reduction in a post-treatment process. These bacteria may be grown from specialized mixes of activated sludge and waste influent by exposing these materials to controlled environments (e.g., in an off-line treatment area). They may then be returned to the main process to perform certain tasks such as converting particulate cBOD into soluble cBOD for utilization, to reduce high solids yield organisms by supplementing the population characteristics with low yield organism characteristics, to provide biological nutrients or oxygenation assistance, to improve nitrification/denitrification efficiency, or to disfavor filamentous biology such as Norcardia sp.

Abstract: A wastewater treatment system includes one or more aeration tanks for receiving wastewater, a controller for controlling the amount of air delivered to each of the one or more aeration tanks by a blower assembly, and a sensor assembly for periodically measuring values corresponding to the amount of dissolved oxygen in at least one of the one or more aeration tanks. When the sensor assembly measures values that are less than a low setpoint value, the controller causes the blower assembly to incrementally deliver more air until the sensor assembly measures values that are not less than the low setpoint value. When the sensor assembly measures values that exceed the low setpoint value, the controller causes the blower assembly to incrementally deliver less air until either the sensor assembly measures values that are not greater than the low setpoint value, or the blower assembly reaches a preselected low operating threshold.

Abstract: A process for treating wastewater containing nitro-hydroxy-aromatic compounds using oxidative sub-critical conditions. The wastewater to be treated is adjusted to contain excess hydroxide equivalent to greater than three moles of free hydroxide per mole of total nitro-hydroxy-aromatic compounds, and a sub-stoichiometric amount of an oxidant is supplied to the wastewater. The nitro-hydroxy-aromatic compounds may include nitro-phenol salts or nitro-cresol salts.

Abstract: A hybrid method and system of treating wastewater with reduced energy usage is disclosed. The treatment system has a sorption system, an anaerobic digester that digests or converts at least a portion of the solids or sludge from the sorption system, and an aerobic treatment tank that partially reduces oxygen demand of a portion of the sludge from the sorption tank.

Abstract: A modular, vertical bioreactor system includes a plurality of vertical bioreactor chambers each of which encloses an interior volume and has a height dimension which is greater than its width dimension; a drain manifold which maintains the bioreactor chambers in a spaced apart relationship and defines a fluid channel which is in fluid communication with each of the vertical bioreactor chambers; and, a fluid delivery assembly which delivers a fluid to each of the bioreactors. The system may be reconfigured so as to accommodate varying applications. The system may be integrated with an aquaculture system.

Abstract: A system and method are provided for removal of undesirable substances from a body of liquid. The system can include an aeration structure having a continuously inclined surface configured to provide an interaction of air bubbles against substantially an entire length of the continuously inclined surface while the air bubbles are moving toward a top of the body of liquid. The continuously inclined surface can be substantially submerged in the body of liquid. A bio-film of diverse bacteria colonies is disposed on the continuously inclined surface, and a high surface area-to-volume structure is located in proximity to the aeration structure, upon which a bio-film of bacteria colonies can be formed.

Abstract: An anoxic packed-bed biological and chemical system for removing nitrates/perchlorate from water includes a vessel having a distribution plate that partitions the vessel into a lower influent-receiving chamber and an upper biological and chemical denitrification chamber. A granular media is supported by the distribution plate to provide a packed bed that has sites for biological growth. A recycle system recycles partially treated water into the closed lower end of the vessel for upflow through the distribution plate.

Abstract: Methods and systems are provided for treating wastewater to simultaneously remove nitrogen, carbon, and phosphorus. The process includes an anoxic tank that receives at least two streams, including plant influent wastewater and return activated sludge. These streams are mixed in the anoxic tank to promote phosphorus release and fermentation of particulate and dissolved organic matter. The mixed liquor is transferred to an aerated tank having low dissolved oxygen concentrations to promote development of phosphorus-release bacteria that is eventually recycled to the anoxic tank by way of the return activated sludge. Simultaneous nitrification, denitrification, and phosphorus release occur in the aerated tank. A membrane tank separates treated effluent from activated sludge in a membrane tank.

Abstract: Methods and systems for recovery of phosphorus from wastewater and producing inorganic phosphorus complexes.

Abstract: Process for the biological treatment of organic wastes, includes a first anaerobic digestion phase and a second aerobic digestion phase in succession, a respective filtration phase of the solid substance being provided between the two digestion phases, a separation phase of the biogas released in the anaerobic digestion phase and a nitrogen recovery phase from the exhaust gases rich in ammoniac substances separated from the aerobic digestion phase. The solid substance coming from each of the filtration phases is separately returned to the respective digestion phase, while the liquid phase coming from the filtration phase downstream of the anaerobic digestion phase is sent to aerobic phase. In the nitrogen recovery phase the gaseous current consisting of exhaust gases rich in ammoniac substances is treated with a solution of carbonic acid supplied in countercurrent in a first gas/liquid contactor to obtain a mixture of nitrogen salts (ammonium bicarbonate, ammonium carbonate, etc.).

Abstract: A system for converting urine into potable water for drinking and use in a hand washing station (165) comprises a commode (100), a three-way valve (110) at the outlet of the commode, a urine reactants tank (145), a storage container (160), a pump (170), and a spigot (175). A user turns an actuator (111) on the valve in one direction to direct feces and feces-plus-urine into a reactants tank for feces, and in another direction to direct urine into the urine reactants tank. The urine reactants tank contains a plurality of baffles (210) separating the tank into chambers. A first chamber contains algae and microorganisms supplied by a seed (150). These organisms absorb nutrients from the urine as they grow into a mass (152). A last chamber contains only purified water which flows from the tank into the storage container from which it can be pumped to the spigot.

Abstract: Methods and systems for utilizing biological wastewater treatment processes to remove nutrients from wastewater containing reduced sulfide compounds may include treating the wastewater in an anaerobic zone, an anoxic zone, and an aerobic zone. The wastewater is first treated in the anaerobic zone to uptake residual biodegradable organic material using specialized bacteria known as phosphorus accumulating organisms (“PAOs”) and glycogen accumulating organisms (“GAOs”). After treatment in the anaerobic zone, the wastewater is treated in an anoxic zone to convert nitrates to nitrogen gas and sulfur to sulfates. Following treatment in the anoxic zone, the wastewater is treated in the aerobic zone to oxidize ammonia to nitrate and to complete removal of phosphorus. After treatment in the aerobic zone, the wastewater may be treated in other zones, or may be delivered to a liquid-solids treatment stage.

Abstract: Provided are an apparatus and a method for river water purification using a treatment soil layer and a permeable filtering medium layer. The river water purification apparatus includes a treatment soil layer and a permeable filtering medium layer which are sequentially and alternately stacked. The treatment soil layer includes a plurality of unit soil layers which are arranged at intervals. A reservoir part which stores a predetermined amount of river water and supplies the river water to an inside of the unit soil layer is provided in an upper end part of the unit soil layer. The permeable filtering medium layer has a higher hydraulic conductivity than that of the treatment soil layer. The river water purification apparatus increases a treatment flux of river water regardless of a coefficient of water permeability of soil and effectively removes nitrogen, phosphorus and nutrient salts by stably forming an anaerobic condition.

Abstract: A wastewater treatment method using annularly arranged microorganism carriers in a reaction tank, which defines therein an upper reaction area, a lower reaction area and a passage area surrounded by the microorganism carriers and kept in communication between the upper reaction area and the lower reaction area. Microorganisms including nitrifying bacteria and autotrophic denitrifying bacteria are attached to the surface of each microorganisms carriers and suspending in the water of the reaction tank for causing Anammox reaction to convert NH4+ and NO2? in wastewater into nitrogen gas, achieving removal of total nitrogen compounds from water. The microorganism carriers are used to retain microorganisms in the reaction tank, enhancing the treatment efficiency.

Abstract: A biological nutrient removal (BNR) system to treat a typical U.S. municipal/domestic wastewater. This BNR system consists of four main directly interflowing of anaerobic, aerobic, anoxic and re-aeration. In the municipal/domestic wastewater treatment industry, the past multi-stage suspended waste activated sludge treatment facilities have been adding coagulant chemicals such as alum to remove total phosphorous (TP) and total nitrogen (TN) to 1.0 mg/l and 3.0 mg/l, respectively. This BNR system is a unique activated sludge biological configuration capable of treating wastewater biologically for clarifier effluent TP and clarifier effluent TN to a level less than 1.0 mg/l for each pollutant without any coagulant chemical additions.

Abstract: A method and system for treating domestic sewage and organic garbage are provided. The method comprises the steps of: multi-phase separation, retting, generating sewage gas, and optional biological denitrification and dephosphorization, which can convert the domestic sewage and organic garbage into clear water, sewage gas, organic manure and sludge. The system comprises a multi-phase separation device, a retting device, a sewage gas generating device and a biological denitrification and dephosphorization device, which can treat the domestic sewage and organic garbage effectively and environmental friendly to achieve a reduction in pollution emission.

Abstract: Methods and systems are provided for treating wastewater to simultaneously remove nitrogen, carbon, and phosphorus, while recovering energy in the form of methane and carbon dioxide. An ammonia-containing stream is directed to a pretreatment tank that produces excess sludge, biogas, and a pretreated stream. The pretreated stream has at least 45% less carbon than the ammonia-containing stream. The pretreated stream is then directed to an anoxic tank, which promotes phosphorus release and fermentation of particulate and dissolved organic matter. The mixed liquor is transferred to an aerated tank having low dissolved oxygen concentrations to promote development of phosphorus-release bacteria that is eventually recycled to the anoxic tank by way of the return activated sludge. Simultaneous nitrification, denitrification, and phosphorus release occur in the aerated tank. A membrane tank separates treated effluent from activated sludge in a membrane tank.

Abstract: The present invention relates to systems and processes of wastewater treatment and, in particular, to systems and methods of treating wastewater utilizing biological treatments utilizing two mixed liquor recycle streams for nutrient removal.

Abstract: Wastewater treatment systems, methods and apparatus for polishing a wastewater stream comprising a plurality of contaminants are provided. One system includes a vessel containing a plurality of natural media filtration agents selected to remove selected ones of the plurality of contaminants from the wastewater stream. In one embodiment, the vessel includes a bed of bauxite residue and at least one other natural media filtration agent. In another embodiment, the vessel includes a bed of compost and at least one other natural media filtration agent. The vessel includes a wastewater inlet that is in fluid communication with one or more of the natural media filtration agents. The vessel includes a wastewater outlet that is in fluid communication with one or more of the natural media filtration agents.

Abstract: Methods and compositions for removing radium from drinking water using a natural zeolite.

Abstract: In a sewage disposal system, a de-nitrification station is configured as a heap of foam cubes located in an airtight enclosure from which oxygen is excluded. Carbon is added to the incoming nitrified water. The heap of foam cubes is arranged as a free-draining trickle filter, but here under asphyxiant conditions in the enclosure. Anaerobic microbiological reactions reduce the nitrate to nitrogen gas. Effluent from the de-nitrifier is polished by feeding back a fraction of the effluent through the aeration station from which the nitrate water is derived, or a separate polishing station can be provided.

Abstract: A wastewater treatment apparatus of the present invention is configured to biologically filter wastewater through multimedia by consecutively performing two stages (the first and second stages) for a multimedia biological filtration process. A carbon source and coagulant are respectively injected during the first and second multimedia biological filtration processes. The first stage multimedia biological filtration process is carried out in anoxic conditions and the second stage multimedia biological filtration process is carried out in aerobic conditions. The media for the first and second stage biological filtration processes are arranged in large-middle-middle large-small size. Thus, the present invention can secure excellent treated water while minimizing loss of water-head by maximizing reflux capability of solids.

Abstract: In accordance with particular process, method and system aspects there is provided a biological manner of treating water/wastewater. Treatment is undertaken in bioreactor configured to treat the water/wastewater through a first process of denitrification followed by a second process of biological phosphorus removal. The bioreactor may be defined by multiple stages arranged in compact vertical alignment, for example, to reduce a footprint of the bioreactor and to feed the water/wastewater between the stages using gravity. The stages may comprise, in order, a Deaeration stage, an Anoxic stage, an Anaerobic stage, and an Aerobic stage. Continuous vacuum operation in the Deaeration stage enhances the physical removal of oxygen and other dissolved gases.

Abstract: The methods are utilized to recover ammonium from waste water using CO2 acidified absorption water. The process is particularly suited for utilization of cellular matter and a CO2 rich tail gas from a syngas fermentation process and derives significant benefit from the recovery of ammonium bicarbonate and ammonium carbonate. Ammonia and ammonium are recovered from the treatment of the syngas as an ammonium rich solution, at least a portion of which is recycled to the fermentation zone to aid in the production of liquid products. A carbon dioxide rich gas produced by fermentation is used to capture the ammonia and ammonium, forming the ammonium rich solution.

Abstract: Wastewater systems, methods and/or kits configured such that one or more screens and one or more gases introduced into the system allow the one or more gases to at least partially contact the one or more screens to dislodge or discourage the media or solids from and/or the biology growth on the one or more screens without substantially affecting the oxygen level in the proximity of the one or more screens.

Abstract: A method for removing phosphorus and nitrogen from an activated sludge wastewater treatment system is provided consisting of one or more anaerobic zones followed by two or more activated sludge reactors operating in parallel each having independent aeration/mixing means, whereby the utilization of the influent organic carbon under anoxic conditions; and thereby, the selection of denitrifying phosphate accumulating organisms (DNPAOs) over non-denitrifying phosphate accumulating organisms (PAOs), is maximized in order to further maximize the removal of phosphorus and nitrogen in the wastewater treatment system.

Abstract: Provided is a method for recovering high-concentration and high-purity amine from amine-containing waste water generated from nuclear power plants and thermal power plants. The method includes: capturing amine and concentrating waste water using a cation exchange resin; separating amine from the concentrated amine-containing waste water; and carrying out further separation of amine via distillation. The method may be applied to treat amine, which causes an increase in biochemical oxygen demand (BOD) and total nitrogen concentration, drastically at the time of its generation from waste water of nuclear power plants and thermal power plants. In this manner, the method may prevent an increase in load of existing waste water treating plants and avoid a need for modifying the equipment in the existing plants.

Abstract: An apparatus and methods for converting seawater to drinking water at room temperature include using the processes of osmosis, vacuum stripping, nanofiltration, ion exchange, and breakpoint chlorination, to provide a low-cost alternative to prior seawater conversion methods.

Abstract: The processes are utilized to recover ammonium from waste water using CO2 acidified absorption water. The process is particularly suited for utilization of cellular matter and a CO2 rich tail gas from a syngas fermentation process and derives significant benefit from the recovery of ammonium bicarbonate and ammonium carbonate. Ammonia and ammonium are recovered from the treatment of the syngas as an ammonium rich solution, at least a portion of which is recycled to the fermentation zone to aid in the production of liquid products. A carbon dioxide rich gas produced by fermentation is used to capture the ammonia and ammonium, forming the ammonium rich solution.

Abstract: To provide an apparatus for treating a nitrate waste liquid that includes a denitrification tank (12A) which accommodates active sludge that adsorbs or takes in the radioactive substance in a nitrate waste liquid (11) and in which an anaerobic microorganism that reduces the nitric acid to nitrogen gas grows, and a reaeration tank (14) in which a denitrification-treated liquid (24) treated in the denitrification tank (12A) is aerated and mixed with active sludge.

Abstract: Waste-treatment processes are enhanced through generation and introduction of specific biological populations customized to perform or favor specific tasks either during the main process, for the formation or precipitation of certain biological nutrients, or to accomplish solids formation reduction in a post-treatment process. These bacteria may be grown from specialized mixes of activated sludge and waste influent by exposing these materials to controlled environments (e.g., in an off-line treatment area). They may then be returned to the main process to perform certain tasks such as converting particulate cBOD into soluble cBOD for utilization, to reduce high solids yield organisms by supplementing the population characteristics with low yield organism characteristics, to provide biological nutrients or oxygenation assistance, to improve nitrification/denitrification efficiency, or to disfavor filamentous biology such as Norcardia sp.

Abstract: To provide an apparatus for treating a radioactive nitrate waste liquid that includes a denitrification tank (12A) which accommodates active sludge that adsorbs or takes in the radioactive substance in a nitrate waste liquid (11) and in which an anaerobic microorganism that reduces the nitrate to nitrogen gas grows, and a reaeration tank (14) in which a denitrification-treated liquid (24) treated in the denitrification tank (12A) is aerated and mixed with active sludge. A pH adjuster (21), a carbon source (22), and nitrogen gas are supplied to the denitrification tank (12A) so as to separate a denitrified liquid into a solid content and the denitrification-treated liquid (24) by using a first solid-liquid separating film (25), and the denitrification-treated liquid (24) treated with the active sludge in the reaeration tank (14) is reaerated and separated into a solid content and a reaeration-treated liquid (27) by using a second solid-liquid separating film (28).

Abstract: An iron composition having a plurality of elemental components is disclosed. The major component is an iron component of at least about 68% to about 92% iron by weight. Other components by weight include manganese; cerium; carbon; phosphorous; sulfur; aluminum; silicon; chromium; copper; and zinc. Combined with layers of sand, brick chips and/or charcoal, the iron composition can be used to create a water filter for filtering inorganic arsenic species and soluble metal ions out of water. To enhance hydrous ferric oxide complexation and precipitation, the iron composition may be treated with food grade acids or a water mixture.

Abstract: A waste treatment process comprised of an ammonification system to convert soluble organic nitrogen into ammonia nitrogen, followed by a physico-chemical process to remove a substantial amount of the ammonia as a recovered ammonium sulfate fertilizer or ammonium hydroxide (“aqua ammonia”), and followed by an ammonia oxidation process to oxidize the remaining ammonia from the physico-chemical process. The process reduces ammonia and carbonaceous organic matter to less than 10 mg/l and recovers ammonia in the form of either ammonium sulfate or ammonium hydroxide.

Abstract: This invention relates to a method that uses heterothrophic ammonia oxidation bacteria (HAOB) to remove carbon and nitrogen pollutants in wastewater. The method includes the cultivation of the heterotropic bacteria in an activated sludge environment and the removal of carbon and nitrogen from the wastewater. According to the physiological characteristics of HAOB and the principles of combined oxidation of carbon and nitrogen, the method is able to achieve simultaneous removal of carbon and nitrogen under the condition that the cells do not grow. The process is able to be carried out in the temperature range of 6-40° C. No excess sludge is produced in the process. The invention is able to control the process and product composition of anaerobic ammonia oxidation through the control of organic carbon source, and is able to realize zero-accumulation of NO3?N in the nitrification process. The invention can fully utilize existing activated sludge systems to remove carbon and nitrogen.

Abstract: The invention relates to a method for biologically treating waste water, using a set of micro-organisms having different metabolic spectra, in order to eliminate carbon and nitrogen, even phosphorus. Some of the micro-organisms are fixed to mobile solid carriers (2) and form a fluidised fixed biomass. Some of the micro-organisms are free to be used in an activated mud treatment. To this end, a first non-aerated treatment zone (21a) is followed by a second aerated treatment zone (21b); the treated effluent is subjected to a solid/liquid separation by flotation (6) at a speed higher than 10 m/H; and part of the mud recovered by flotation is recirculated (8) towards the activated mud treatment, said recirculation being controlled (9, 10, 11) so that the MES concentration of the effluent subjected to the liquid/solid separation remains compatible with the retained flotation.

Abstract: Disclosed are a wastewater treatment plant and a wastewater treatment method. The wastewater treatment plant includes: a reactor including a gas outlet, a treated water outlet, and an inlet through which wastewater and gas are supplied, through which the wastewater is introduced, to perform aeration and denitrification; a sludge separation means including plural reaction unit bodies stacked inside the reactor to divide the interior of the reactor into upper and lower sides and separating sludge in a aeration process by forming a gas hold-up space for collecting the gas rising from a lower portion of the reactor; and a aeration unit introducing gas into the reactor.