Wastewater influent is supplied to an aeration zone having a membrane module. Activated sludge is established in the aeration zone and an oxygen surplus is maintained by controlling a rate of oxygen supplied to the aeration zone. Wastewater influent is mixed with the activated sludge to form a first mixed liquid. A portion of the first mixed liquid is filtered to form a filtrate and unfiltered activated sludge. The unfiltered activated sludge is mixed with the activated sludge in the aeration zone to form the first mixed liquid. A portion of the first mixed liquid is transferred from the aeration zone to an anaerobic zone, and a second portion of first mixed liquid is mixed with activated sludge in the anaerobic zone to form a second mixed liquid. The second mixed liquid is recycled to the aerobic zone.

The present disclosure is directed to ion-exchange systems and devices that can monitor key parameters related to the performance of the ion-exchange device. Specifically, the ion-exchange systems and devices disclosed herein can provide real time voltage drop across groups of membrane pairs using diagnostic spacer borders between the pairs. In addition, the ion-exchange systems and devices disclosed herein can monitor the compression force applied by the compression plates holding the ion-exchange systems and devices together.

A submerged membrane separator includes: a plurality of membrane cartridges arranged at predetermined spaces; a flow generating device for generating flows in one direction along the membrane surfaces of the membrane cartridges; and wall members on both sides of a channel of the flow in the one direction formed between the membrane cartridges adjacent to each other. The membrane cartridges can be attached and detached from another direction substantially orthogonal to the flows in the one direction and substantially orthogonal to the arrangement direction of the membrane cartridges.

In a submerged membrane bioreactor (MBR or SMU), diffusers are used to eject air bubbles, primarily to facilitate the movement of mixed liquor past the membrane surfaces, cleaning and scouring the surfaces of the membranes with the mechanical energy of the combined air/liquid/solids movement. Oxygen transfer from the bubbles into the mixed liquor is often a secondary goal, for supplying oxygen to biological processes. The invention involves the use of a specific bubble diffuser, oriented at a selected upward angle, to enable a single style diffuser to accomplish simultaneous generation of mid-size and fine bubble aeration, with adjustment of the tilt angle varying the percentages of mid-size and fine bubble aeration. The angle selection, along with the number of diffusers and air volume selected, allows achievement of target liquid movement through the MBR.

A desalination method includes the steps of: providing a plurality of reverse osmosis membrane discs at a depth in an ocean selected to provide a hydrostatic pressure; directing seawater through the membrane discs using the hydrostatic pressure; collecting the freshwater directed through the membrane discs; pumping the freshwater to a surface of the ocean; and then transporting the freshwater to land.

A desalination method includes the steps of: providing a plurality of reverse osmosis membrane discs at a depth in an ocean selected to provide a hydrostatic pressure; directing seawater through the membrane discs using the hydrostatic pressure; collecting the freshwater directed through the membrane discs; pumping the freshwater to a surface of the ocean; and then transporting the freshwater to land.

Elastic microfiltration membranes are provided. These membranes may be used in a membrane bioreactor. Due to the elastic nature of the membranes, removal of fouling materials is improved, thereby increasing the efficiency and longevity of the membranes. Methods for forming such membranes and uses of the membranes are also provided, including their use in membrane bioreactors.

A desalination system includes a membrane system submerged in the ocean at a depth selected to provide a hydrostatic pressure and a high pressure side for generating reverse osmosis (RO) to produce freshwater from seawater. The desalination system also includes a pumping system in flow communication with the membrane system configured to pump the freshwater to the surface and to provide a low pressure side for the reverse osmosis (RO), a transport system for transporting the freshwater to land, and a storage system for storing the freshwater on land. A desalination method includes the steps of: providing a plurality of reverse osmosis membrane discs at a depth in an ocean selected to provide a hydrostatic pressure; directing seawater through the membrane discs using the hydrostatic pressure; collecting the freshwater directed through the membrane discs; pumping the freshwater to a surface of the ocean; and then transporting the freshwater to land.

A method of operating an immersed microporous membrane module includes a step of monitoring membrane performance to sense the onset of sludging in the module. Differences in permeability between permeation in backwashes, or trends in permeability during backwashing and permeability during permeation, or both, are monitored. Solid deposits formed during the onset of sludging may be removed with an in situ de-sludging process. For example, the deposits may be removed by stopping permeation while aerating the module, optionally at an increased rate. At other times, the module is optionally aerated while permeate is withdrawn at an aeration rate correlated to flux. The method may be used in particular with a membrane module having parallel textured flat sheet membranes suspended between a pair of vertically oriented headers. An aerator may be made from an open bottomed channel having an array of holes rising and concentrated towards the center of the channel.

In an immersed membrane system, the influent flows into an open membrane tank. The membrane tank can have multiple horizontally spaced immersed membrane units. The immersed membrane units may have flat sheet membrane elements within a membrane case. One or more ducts are provided in the tank for directing the flow of influent to the immersed membrane units. In some examples, the influent is divided into sub-streams that are fed through baffles to a corresponding immersed membrane unit, optionally in generally equal amounts, optionally in a single pass flow pattern. In a process of operating a membrane tank, the influent flow is directed across the bottom of the membrane tank and divided into multiple portions. Each of the multiple portions is fed directly to the bottom of a corresponding immersed membrane unit located in the tank. The influent may be mixed liquor in a membrane bioreactor (MBR).