The high water recovery hybrid membrane system for desalination and brine concentration combines nanofiltration, reverse osmosis and forward osmosis to produce pure water from seawater. The reject side of a nanofiltration unit receives a stream of seawater and outputs a brine stream. A permeate side of the nanofiltration unit outputs a permeate stream. A feed side of a reverse osmosis desalination unit receives a first portion of the permeate stream and outputs a reject stream. A permeate side of the reverse osmosis desalination unit outputs pure water. A draw side of at least one forward osmosis desalination unit receives the reject stream and outputs concentrated saline solution. A feed side of the at least one forward osmosis desalination unit receives a second portion of the permeate stream and outputs a dilute saline stream, which mixes with the first portion of the permeate stream fed to the reverse osmosis desalination unit.

The high water recovery hybrid membrane system for desalination and brine concentration combines nanofiltration, reverse osmosis and forward osmosis to produce pure water from seawater. The reject side of a nanofiltration unit receives a stream of seawater and outputs a brine stream. A permeate side of the nanofiltration unit outputs a permeate stream. A feed side of a reverse osmosis desalination unit receives a first portion of the permeate stream and outputs a reject stream. A permeate side of the reverse osmosis desalination unit outputs pure water. A draw side of at least one forward osmosis desalination unit receives the reject stream and outputs concentrated saline solution. A feed side of the at least one forward osmosis desalination unit receives a second portion of the permeate stream and outputs a dilute saline stream, which mixes with the first portion of the permeate stream fed to the reverse osmosis desalination unit.

Provided are electrodialysis systems comprising a plurality of electrodialysis devices, wherein each electrodialysis device of the plurality of electrodialysis devices has a product inlet stream, a product outlet stream, a brine inlet stream, and a brine outlet stream. The product inlet stream for a first electrodialysis device comprises the brine outlet stream of a second electrodialysis device. Further, a first portion of a feed stream is the brine inlet stream for the first electrodialysis device and a second portion of the feed stream is the brine inlet stream for the second electrodialysis device or a third electrodialysis device.

In an embodiment is provided a process to re-refine used oil that includes introducing a used oil and a solvent to a separation unit under separation conditions selected to produce a purified oil product, the separation unit comprising a porous membrane, a semiporous membrane, or both; and separating the used oil to obtain an effluent comprising a purified oil product. In another embodiment is provided an apparatus for re-refining used oil that includes a separation unit comprising a porous or semiporous membrane; a used oil feed coupled to an inlet of the separation unit; and an inlet of a diffusate collection unit coupled to an outlet of the separation unit. In another embodiment is provided a composition generated from a membrane separation process that includes a base oil, the composition having a soot content of about 0.05% or less.

An apparatus and process for separating a gas mixture is disclosed. The apparatus includes a plurality of membrane separation stages comprising a first membrane stage, a second membrane stage, and a third membrane stage. Each of the first, second, and third membrane stages are designed to separate a gas stream provided to them into a permeate stream and a retentate stream. The retentate stream provided from the third membrane stage is configured to be withdrawn as a product, further processed, or discarded. The apparatus further includes a gas transport device with an inlet in communication with the gas mixture and an outlet in communication with the first membrane stage. The controller is in communication with at least one measuring device, and the controller adapts a behavior of the gas transport device in response to a measurement of the at least one measuring device.

A feed of at least one of (a) a source liquid including a solvent with a dissolved impurity and (b) a retentate of the source liquid is pumped in a substantially closed loop through a liquid-separation module. The liquid-separation module includes a membrane that passes at least partially purified solvent to a permeate side of the membrane while diverting the impurity in a retentate on the retentate side of the membrane. The purified solvent is extracted from the permeate side of the membrane; and the retentate from the liquid-separation module is pumped to or through a pressurized reservoir with a variable volume for the feed component and recirculated as a component of the feed. Over time, the volume for the feed is reduced and the pressure applied to the feed in the reservoir is increased to balance against an increasing difference in osmotic pressure across the membrane.

A biogas upgrading system can include a multiple stage membrane system that is configured to remove oxygen so that the biogas is upgraded to have a higher concentration of methane, a pre-selected oxygen (O.sub.2) concentration (e.g. less than or equal to 0.2 mol %, etc.), and a pre-selected carbon dioxide (CO.sub.2) concentration (e.g. less than or equal to 5 mol %, etc.). The membrane system can be configured to reject O.sub.2 by utilizing a low CO.sub.2/O.sub.2 selectivity that is within a pre-determined range (e.g. less than 5 or less than 4.5). In some embodiments, the upgraded biogas that is output from the system can be entirely made up of methane, carbon dioxide, and oxygen. In other embodiments, the biogas can be almost entirely composed of these components along with a small amount of nitrogen and a trace amount (e.g. less than or equal to 0.2%-0.1%, etc.) of other components.

The present disclosure relates to a water purification apparatus that comprises a reverse osmosis device, RO-device, producing a purified water flow and to a corresponding method. The proposed method comprises detecting at least one fluid property of purified water in the purified water path and regulating a flow rate of water in the recirculation path to fulfill one or more predetermined criteria of the purified water in the purified water path, based on the at least one detected fluid property. The present disclosure also relates to a computer program and a computer program product implementing the method.

A method of recovering draw agent utilised in a forward osmosis membrane cell, the method comprising the steps of passing diluted draw agent to a vapour-liquid separator; using the vapour-liquid separator to separate draw agent vapour and solvent; and condensing draw agent vapour.

A liquid purification system with purified water mineralization, which uses predominantly water from various resources. The main problem of existing liquid purification systems, particularly membrane systems, is that during purification process not only dangerous debris (residual oil, pesticides, herbicides, heavy metals, bacteria, viruses, mechanical particles and other) are removed, but even minerals necessary for human (calcium, potassium, magnesium, sodium and other), so mineralization step is needed after purification step to normalize mineral composition. In the state of the art are known liquid purification systems with integral mineralization means and also devices for mineralization, which can be connected to liquid purification systems. The working principle of systems, known in the state of the art, is that purified liquid flows through the vessel with mineralization additive, which is partly dissolved, and the liquid becomes mineralized. The main drawback of the systems known in the state of the art is that due to peculiarities of the dissolving process and/or mineralization additive content it is impossible to control mineralization process, so the mineralization level is minor, and the pH is higher than the permitted value. Liquid purification system containing raw liquid line, liquid purification unit, mineralization unit, purified liquid line is characterized in that, mineralization of liquid is done by controlled dispensing of mineralization solution, obtained by selective raw or drainage liquids or their mixture.