A method for biologically treating nitrogen while minimizing energy and carbon source usage uses an aerobic tank, a first anoxic tank, and a second anoxic tank. The method includes introducing feed water by dividedly introducing the feed water to the aerobic tank and the first anoxic tank; converting ammonia nitrogen into nitrate nitrogen in the aerobic tank; converting the nitrate nitrogen into nitrite nitrogen through partial denitrification in the first anoxic tank using organic material contained in the feed water; and converting the nitrite nitrogen and ammonia into nitrogen gas in the second anoxic tank using an anammox microorganism. The ammonia nitrogen is converted by determining aeration intensity, aeration time, and/or aeration amount depending on an ammonia concentration in the aerobic tank. The nitrate nitrogen is converted by determining a reaction time of the first anoxic tank based on nitrate and nitrite concentrations in the first anoxic tank.

A process for aerobic treatment of wastewater is provided, which process comprises: (a) supplying a liquid influent comprising wastewater to a reactor containing granular biomass; (b) subjecting the reaction mixture to aerobic conditions comprising a concentration of dissolved oxygen from 0.1 mg/L to 4.0 mg/L, and a hydraulic retention time from 0.5 to 72 hours; (c) separating the reaction mixture into granular biomass and treated wastewater; and (d) recycling separated granular biomass to the reaction mixture. A bioreactor for the process is also disclosed, comprising a reaction vessel provided with an aeration means, a solids separation device with an inlet in the lower part of the reaction vessel having an outlet line for solids arranged to transport separated solids to a riser driven by airlift action and arranged to transport the solids to the upper part of the reaction chamber.

An apparatus and a method for removing constituents from an influent. The apparatus includes a biological processor that receives a water mixture as influent and outputs a liquor, a solid-liquid separator that receives the liquor and separates the liquor into a liquid and a solid; and a biofilm media that includes at least one media surface. The biofilm media may have a biofilm mass, biofilm volume, biofilm density, biofilm thickness, hydraulic retention time or solids residence time. The at least one media surface grows a biofilm that removes one or more constituents contained in the influent. The biofilm mass, biofilm volume, biofilm density, biofilm thickness, hydraulic retention time or solids residence time can be controlled by at least one of a physical process, a biological process or a chemical process.

A method and device for in-situ enriching Anammox bacteria by conventional activated sludge, which belongs to a biological wastewater treatment technology. The device comprises a raw water tank, an anammox reactor and a water outlet tank. The method comprises the following steps: (1) taking traditional activated sludge from a municipal wastewater plant as inoculation sludge without special requirements on form of reactor and water quality of inflow; the mainstream anammox in-situ enrichment being realized mainly in three stages; (2) carbon and phosphorus removal stage, wherein carbon and phosphorus removal sludge is domesticated through joint control of aerobiotic time and sludge retention time; (3) partial nitrification stage, wherein the stage is realized through gradually extending the aerobiotic time; (4) anammox bacteria in-situ enrichment stage, wherein good culture retention conditions are provided through the artificial regulation strategies: (5) the method of the present invention only needs to construct or utilize the existing traditional activated sludge wastewater biological treatment devices and equipment without adding agents, which is conducive to the application of practical engineering.

Wastewater containing a significant level of dissolved readily biodegradable organic compounds matter, such as short-chain fatty acids, and ammonia can be efficiently treated to remove most or all of the organic compounds and the ammonia, with the production of microbial storage compounds such as polyhydroxylkanoates, by (i) subjecting the wastewater storage compound-accumulating microorganisms (SCAM) in the presence of oxygen, (ii) subjecting at least part of the resulting partly treated wastewater to ammonia-oxidising microorganisms (AOM) in the presence of oxygen and (iii) feeding a gas containing molecular carbon dioxide produced during step (ii) to step (i) so as to lower the pH in step (i).

A common final clarifier is provided downstream of a two-stage or three-stage activated sludge (AS) system that includes: (A) one or more flow equalization basin (FEB) reactors and a nitritation reactor as the first AS stage, and an anammox reactor as the second AS stage, or (B) a carbonaceous biological oxygen demand (BOD) removal reactor and one or more FEBs as the first AS stage, a nitritation reactor as the second AS stage, and an anammox reactor as the third AS stage. A first return activated sludge (RAS) flow is conducted from the final clarifier to the first AS stage and a second segregated RAS flow is conducted to the second AS stage. Alternatively, a third segregated RAS flow is conducted to the third AS stage.

Methods and systems for controlling a denitrification reaction in a biological nitrogen removal reactor including denitrifying bacteria to favor denitratation of nitrate to nitrite and limit denitritation of nitrite to nitrogen gas are disclosed. pH, dissolved oxygen levels, solids retention time, and chemical oxygen demand to nitrogen ratio are controlled to favor this reaction. Wastewater or contaminated groundwater including concentrations of ammonium and nitrate are continuously fed to the biological nitrogen removal reactor along with a source of carbon and electrons as an influent, which is treated to form a nitrite effluent. The nitrite effluent may then be fed to an anammox reactor including anammox bacteria for production of nitrogen gas. The system may be operated under substantially anoxic conditions, which provides significant cost savings without sacrificing efficiency or productivity compared to traditional wastewater treatment systems and processes.

Provided is a method for treating ammoniacal nitrogen in wastewater performed via biologically oxidizing ammoniacal nitrogen, and producing nitrite nitrogen and nitrate nitrogen at a desired rate. In the method, ammoniacal nitrogen is oxidized by bacterial sludges to produce at least either of nitrite nitrogen and nitrate nitrogen. Specifically, the method includes an inactivating treatment step of treating the bacterial sludges with an inactivating operation via sterilizing bacteria or causing bacteriostasis, and a nitrifying treatment step of oxidizing the ammoniacal nitrogen by the bacterial sludges thus treated in the inactivating operation. Production amounts of the nitrite nitrogen and the nitrate nitrogen are controlled by adjusting biomass of the bacterial sludges to be treated in the inactivating operation, and/or a time interval between the inactivating operations each repeatedly performed in combination with the nitrifying treatment step.

A method for treating middle and mature landfill leachate by endogenous denitrification combined autotrophic nitrogen removal process, which belongs to a field of biological treatment of high-ammonia-nitrogen wastewater. The middle and mature landfill leachate firstly enters a PN/ED-SBR reactor to perform in an A/O (anaerobic/aerobic) mode, microorganisms in an anaerobic stage absorb an external carbon source and store the external carbon source as an intracellular carbon source, partial nitrification is performed in the aerobic stage, and the ammonia nitrogen in inlet water is completely oxidized into nitrite nitrogen; after the reaction is finished, an effluent containing nitrite nitrogen and middle and mature landfill leachate are mixed and then enter an AMOX-UASB reactor to perform anammox reaction, the effluent of the reactor is pumped into the PN/ED-SBR reactor again to perform in the anoxic mode, and oxidized nitrogen is removed through endogenous denitrification.

Disclosed is a carrier, of which biofilms are appropriately adjustable in thickness. In accordance with an aspect of the present disclosure, there is provided a complex carrier included in one component of a sewage treatment apparatus to allow microorganisms to be attached and grown therein. The complex carrier includes a first carrier having a plural spaces for microorganisms to be attached therein to allow microorganisms to be attached and grown therein; and a second carrier having a structure capable of penetrating or passing through the spaces of the first carrier to adjust the thickness of biofilms formed in the spaces of the first carrier.