An apparatus and method for selecting, retaining or bioaugmenting solids in an activated sludge process for improving wastewater treatment using screens. The screens can be used to separate and retain solids based on size, compressibility or shear resistance. The screens are used to separate and select slow growing organisms, faster settling organisms, or materials added to absorb, treat or remove constituents in the activated sludge process. A swapping screen arrangement provides another means of selecting various particles. The exposed shear rate or time, particle compression, or SRTs can be adjusted manually and/or automatically in response to detected readings from an instrument such as a spectrophotometer or other optical approaches to optimize selection of organisms. The present disclosure may be configured as an activated sludge system operated at different solids residence times (SRT) for different solids fractions allowing slow growing organisms to get established in competition with faster growing organisms or aggregates thereof.

A system for mixing and mixing processes and structures are disclosed. In addition a nozzle used for mixing is disclosed.

The system relates to a disk filter for effectively preventing scale formation in a water treatment process, and to a water treatment apparatus and method using the same. The disk filter includes a housing having a cylindrical shape, a raw water inlet formed at a predetermined position on the side surface of the housing, a raw water outlet formed at a central region in the bottom of the housing, a backwash water outlet formed at a central region in the top of the housing, a ceramic filter provided in a circular disk shape inside the housing, and a scale formation inhibitor loaded in a flow channel formed inside the ceramic filter, wherein raw water introduced via the raw water inlet passes through the ceramic filter and then through the flow channel filled with the scale formation inhibitor, and is then discharged via the raw water outlet.

A process for converting ammonium (NH.sub.4.sup.+) of a mainstream of a wastewater plant to dinitrogen gas (N.sub.2), including the consecutive steps of i.) removing biodegradable carbon compounds in the mainstream, ii.) converting ammonium (NH.sub.4.sup.+) in the mainstream to nitrite (NO.sub.2.sup.) in an aerated biological process containing ammonium oxidizing bacteria (AOB) in a nitration vessel (133a-133d); and iii.) denitrifying the resulting stream from step ii.) to dinitrogen gas in an anammox vessel (200). Growth of nitrite oxidizing bacteria (NOB) in step ii.) is prevented by periodically subjecting the bacteria in said nitration vessel (133a-133d) to water suppressing growth of nitrite oxidizing bacteria (NOB).

A method of treating wastewater is disclosed in which a flow equalization reactor is provided that includes at least one wastewater treatment zone. A first wastewater treatment process is performed in the at least one wastewater treatment zone, which can be switched to a second wastewater treatment process. The flow equalization reactor is designed with a variable liquid depth and volume that can operated as a mixed wastewater zone, an anaerobic reactor zone, an anoxic reactor zone or an aerobic reactor zone. The equalization reactor provides sufficient variable liquid depth and volume above a minimum liquid depth and residual volume to provide the necessary hydraulic flow equalization or surge volume to achieve a relatively constant effluent pumping rate or feed forward flow rate over 24 hours per day, seven days per week into the downstream biological treatment processes, clarifiers, filters, or disinfection units, etc.

The present application provides a method for treating and recycling organic wastewater, comprising: 1) pretreating the organic wastewater; 2) subjecting an effluent obtained after pretreatment in step 1 to a heterogeneous Fenton reaction with Hangjin clay-supported nano-Fe.sub.3O.sub.4 as a catalyst, separating the catalyst from a reaction solution after completion of the reaction, and subjecting the reaction solution to a reaction to remove COD; 3) subjecting an effluent obtained in step 2 to an anaerobic ammonia oxidation reaction to denitrify by ammonia nitrogen reacting with nitrite nitrogen; 4) subjecting an effluent obtained in step 3 to an aerobic microbial decomposition and ultrafiltration membrane separation to remove COD and ammonia nitrogen; 5) filtering an effluent obtained in step 4 to remove large particles; 6) supplying an effluent obtained in step 5 to an RO system, and using an effluent from the RO system as circulating cooling water, and subjecting concentrated water from the RO system to a softening treatment; and 7) supplying softened concentrated water obtained in step 6 to an NF system for treatment, evaporating an effluent obtained after the treatment to recover NaCl, and returning a resulting concentrated water to step 1. The present application also provides a device for implementing the method for treating and recycling an organic wastewater.

A device and a method for maintaining the stability of anaerobic ammonium oxidation (anammox) by using a combined zeolite filler to resist water quality fluctuations are provided.

The device includes a water inlet tank, an anammox reactor, and a water outlet tank, where the anammox reactor is filled with the combined zeolite filler maintained in a state of suspension, domestic sewage enters the anammox reactor through a water inlet pump, and effluent water enters the water outlet tank through an overflow port. The device combines the physical characteristics of zeolite adsorption of ammonium with the anammox process: when the concentration of ammonium in the influent water is too high, the zeolites will temporarily store the excess ammonium adsorbed; when the concentration of nitrite in the influent water is too high, the zeolites are capable to release the stored ammonium into a liquid phase through balanced adsorption desorption.

Described herein are systems and methods for treatment of contaminated water employing a mobile supported biofilm. The treatment systems include a bioreactor, a mobile biofilm disposed within the bioreactor, and a solid-solid separation unit attached to the bioreactor. The solid-solid separation unit is adapted to receive an effluent stream from the bioreactor, wherein the effluent contains the mobile biofilm, and separate at least a portion of the mobile biofilm from the effluent and return it to the bioreactor.

Processes are disclosed for the microbial nitritation of ammonia that attenuate the production of at least one of nitrate anion and nitrous oxide. The processes use an ME biocatalyst having a highly porous, hydrophilic polymeric structure with ammonia-oxidizing microorganisms substantially irreversibly retained therein. The processes are particularly useful for integration with anammox processes.

A process is provided, comprising: (a) supplying ammonium-containing wastewater to a reactor containing granular sludge comprising granules having a core of anammox bacteria and an outer rim of ammonia oxidizing bacteria; (b) subjecting the wastewater to ammonium oxidation at a temperature between 5 to 25? C., a dissolved oxygen concentration between 0.4 mg/L to 4.0 mg/L, and a hydraulic retention time between 0.5 hours to 1.5 days, obtaining a nitrogen gaseous stream and a dispersion of granular and non-sludge in treated wastewater; and (c) separating the dispersion into a granular sludge stream and a stream of treated wastewater and non-granular sludge, and (d) recycling the granular sludge to the reactor while discharging the non-granular sludge, wherein the granular sludge has a reactor retention time at least ten times the hydraulic retention time, and wherein the retention time of non-granular sludge is no more than three times the hydraulic retention time.