A reactor for treating water, the reactor comprising a buoyant structure for supporting at least one cell for suspension in a body of water in use, wherein each cell is removeably attachable to the buoyant structure and is arranged to house biomedia. A water treatment system comprising the reactor in a body of water. A method of treating water comprising passing water to be treated through the reactor in a body of water.

A system and a method comprise an upstream chamber is configured to receive a variable input flow of a wastewater mixture having a maximum input flow rate. A downstream chamber is adjacent to the upstream chamber. An effluent baffle wall separates the downstream chamber from the upstream chamber. An effluent flow port is located in the effluent baffle wall. The effluent flow port comprises a first orifice configured to produce a first modulated flow of the wastewater mixture from the upstream chamber to the downstream chamber, and a second orifice being positioned above the first orifice. The second orifice is configured to produce a second modulated flow having a second flow rate, wherein a combined flow rate including the first and second flow rates is less than the maximum input flow rate.

A system and a method comprise an upstream chamber is configured to receive a variable input flow of a wastewater mixture having a maximum input flow rate. A downstream chamber is adjacent to the upstream chamber. An effluent baffle wall separates the downstream chamber from the upstream chamber. An effluent flow port is located in the effluent baffle wall. The effluent flow port comprises a first orifice configured to produce a first modulated flow of the wastewater mixture from the upstream chamber to the downstream chamber, and a second orifice being positioned above the first orifice. The second orifice is configured to produce a second modulated flow having a second flow rate, wherein a combined flow rate including the first and second flow rates is less than the maximum input flow rate.

A wastewater treatment system includes a foundation layer and a cylindrical wastewater treatment tank provided on the foundation layer, where the wastewater treatment tank includes a first treatment space enclosed by a side wall; the first treatment space is internally divided into an anaerobic zone, an anoxic zone, and an aerobic zone; each zone runs vertically from a top of the wastewater treatment tank to a bottom thereof, and each two adjacent zones are communicated in sequence, such that wastewater in the wastewater treatment tank flows through the anaerobic zone, the anoxic zone and the aerobic zone in sequence in a vertical serpentine path; a plurality of layers of process platforms are arranged in sequence from top to bottom around the wastewater treatment tank above the foundation layer; and the process platforms are configured to carry secondary sedimentation devices, advanced treatment devices and a power distribution device.

A wastewater treatment system includes a foundation layer and a cylindrical wastewater treatment tank provided on the foundation layer, where the wastewater treatment tank includes a first treatment space enclosed by a side wall; the first treatment space is internally divided into an anaerobic zone, an anoxic zone, and an aerobic zone; each zone runs vertically from a top of the wastewater treatment tank to a bottom thereof, and each two adjacent zones are communicated in sequence, such that wastewater in the wastewater treatment tank flows through the anaerobic zone, the anoxic zone and the aerobic zone in sequence in a vertical serpentine path; a plurality of layers of process platforms are arranged in sequence from top to bottom around the wastewater treatment tank above the foundation layer; and the process platforms are configured to carry secondary sedimentation devices, advanced treatment devices and a power distribution device.

Disclosed is an apparatus for treating wastewater that includes a tank having a wall, defining an inner surface, and a floor; a clarifier having an outer surface selectably fixed relative to said tank; and a diffuser; wherein the inner surface, the outer surface and the diffuser are configured to compel wastewater in the tank to define a flow along a direction up the outer surface and down the inner surface. A method of treating wastewater also is disclosed.