A wastewater treatment system includes a first sub-system having a biological treatment unit and a second sub-system having a dissolved air flotation unit. A method of treating wastewater includes directing a first stream of wastewater to a biological treatment unit and directing an overflow stream of wastewater to a dissolved air flotation unit. A method of facilitating treatment of overflow wastewater in a biological treatment system includes connecting an overflow treatment system in a parallel configuration with the biological treatment system, the overflow treatment system having a dissolved air flotation unit, and directing a fraction of activated sludge from the biological treatment system to the overflow treatment system.

An object of the present invention is to provide a method for producing recycled water, according to which when recycled water is prepared from waste water, chemical cleaning of a membrane can be significantly reduced and fouling of the membrane can be eliminated by substantially only washing with water. The above object is achieved by providing a method for producing recycled water, the method including the following steps (A) to (D) of: (A) subjecting waste water to an anaerobic treatment and an aerobic treatment which are carried out by microorganisms, the waste water having been discharged during a production process of a PHA; (B) subjecting treated water obtained in step (A) to pretreatment filtration performed by a membrane bioreactor method; (C) subjecting the treated water obtained in step (B) to an alkali treatment; and (D) filtering, through an ion removal membrane, the treated water obtained in step (C).

This disclosure relates to physical selection, deselection or outselection for smaller, less dense, sheared or compressed particles in sludge, wherein the first deselection step occurs at the reactor or at a clarification step, by separately deselecting for such particles and then a second deselection step occurs in an external selector. This double deselection promotes the more efficient removal of slow settling particles, while simultaneously allowing for maintenance of multiple solids residence times for fast and slow growing organisms. The deselection in a clarifier occurs typically at the periphery of the tank or at the surface of a blanket using a positive or negative pressure device. Structures such as slotted or perforated plates, pipes or manifolds can be used to assist in such deselection. Baffles can also be used for such deselection.

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 method and system for deselecting biological solids in an influent containing water. The method and system include supplying an influent to an inlet of a reactor comprising at least one of a bioreactor, an internal deselector, a particle deselector, and one or more return lines; dispersing the influent in the bioreactor to form a solid-liquid mixture containing biological solids; retaining, retarding, or providing a differential of, by the internal deselector, biological solids from the solid-liquid mixture to form a deselected solid-liquid mixture and returnable biological solids; feeding said deselected solid-liquid mixture to the particle deselector; deselecting, by the particle deselector, remainder biological solids from the deselected solid-liquid mixture; and supplying, by the one or more return lines, the returnable biological solids to the bioreactor.

Systems and methods for enabling dynamic volumetric transitioning and segmentation of treatment conditions are disclosed. Such treatment conditions may include, by way of example, systems and methods for dynamically transitioning treatment environments within a reactor for activated sludge treatment processes. Such environments may include anaerobic, anoxic, fermentation, suboxic, and aerobic environments.

A wastewater treatment system including, storing in a storage unit, a wastewater storage tank for storing wastewater containing organic matter, an ozone treatment device for treating wastewater with ozone, thereby reducing the molecular weight of organic matter contained in wastewater, a wastewater circulating structure for conveying wastewater stored in the wastewater storage tank to the ozone treatment device and circulating the ozone-treated wastewater back into the wastewater storage tank, and a biological treatment tank for bringing aerobic microorganisms into contact with wastewater, conveyed from the wastewater storage tank, which contains the ozone-treated wastewater, thereby reducing organic matter contained in wastewater.

Disclosed is a municipal sewage nitrogen removal treatment device, comprising a reaction pool. A water inlet pipeline, a water outlet pipeline and a reflux pipeline are connected to the reaction pool, and the reflux pipeline communicates with the water inlet pipeline by using a reflux element. A surface aerator is arranged in the reaction pool. The reaction pool comprises a reaction zone and a settling zone, the settling zone is located at the bottom of the reaction zone, and the reaction zone is provided with a flow deflector. The flow deflector is provided with a plurality of flow deflecting channels, the sidewall of the flow deflecting channel is a rough surface, and microorganisms in the reaction pool are able to attach to the sidewall of the flow deflecting channel. The present disclosure further provides a treatment method using the municipal sewage nitrogen removal treatment device above.

A process for the treatment of wastewater is disclosed, which comprises (a) contacting the wastewater with fast settling sludge from step (c) in an anaerobic zone, obtaining a mixture of wastewater and sludge; (b) subjecting the mixture from step (a) and slow settling sludge from step (c) to an aerobic zone, obtaining a water and sludge mixture; (c) subjecting a first part of the mixture from step (b) to a sludge selection step, wherein sludge is selected based on settling velocity and a first portion containing slow settling sludge and a second portion containing fast settling sludge are collected, wherein average settling velocity of the fast settling sludge is greater than that of the slow settling sludge, and wherein the first portion is returned to step (b) and the second portion is returned to step (a); and (d) separating sludge from a second part of the mixture from step (b).

The invention relates to a bioreactor for treating water fluid(s), and/or for producing a desired end product by biomass and/or for producing biomass. The invention relates also to methods for manufacturing and using such a bioreactor. The bioreactor (BR) includes at least a first processing unit (Z.sub.F), a second processing unit (Z.sub.2), a last processing unit (Z.sub.L), and, optionally, additional processing unit(s) (Z.sub.3, Z.sub.4) between the second processing unit (Z.sub.2) and the last processing unit (Z.sub.L) in a plug flow configuration; at least one forward circulation system (FCS, FCS1, FCS2) for circulating biomass (BM) from the first processing unit (Z.sub.F), to the last processing unit (Z.sub.L) and/or to additional processing unit(s) (Z.sub.3, Z.sub.4); and at least one reverse circulation system (RCS, RCS1, RCS2) for circulating biomass (BM) from the last processing unit (Z.sub.L) and/or from the additional processing unit(s) (Z.sub.3, Z.sub.4) to the first processing unit (Z.sub.F).