A system and a method for removing gas field chemicals from a feed stream are provided. An exemplary method includes performing a forward osmosis on a feed stream including gas field chemicals to form a concentrated feed stream, and treating the concentrated feed stream in an electrochemical process to form treated water.

A method and system for reversibly converting water between an initial ionic strength and an increased ionic strength, using a switchable additive, is described. The disclosed method and system can be used, for example, in distillation-free removal of water from solvents, solutes, or solutions. Following extraction of a solute from a medium by dissolving it in water, the solute can then be isolated from the aqueous solution or salted-out by converting the water to a solution having an increased ionic strength. The solute then separates from the increased ionic strength solution as a separate phase. Once the solute is, for example, decanted off, the increased ionic strength aqueous solution can be converted back to water having its original ionic strength and reused. Switching from lower to higher ionic strength is readily achieved using low energy methods such as bubbling with CO.sub.2, CS.sub.2 or COS. Switching from higher to lower ionic strength is readily achieved using low energy methods such as bubbling with air, heating, agitating, introducing a vacuum or partial vacuum, or any combination or thereof.

The invention generally relates to osmotically driven membrane systems and processes and more particularly to systems and processes for handling feed streams without pretreatment and increased brine concentration for zero liquid discharge, including forward osmosis separation (FO), direct osmotic concentration (DOC), pressure-assisted forward osmosis (PAFO), and pressure retarded osmosis (PRO). The system includes: a plurality of forward osmosis units, each having a semi-permeable membrane assembly and a tank; and a separation system in fluid communication with the plurality of forward osmosis units and configured to separate the dilute draw solution into the concentrated draw solution and a solvent system.

The invention relates to a ternary sewage treatment method integrating microbial fuel cells with anaerobic acidification and forward osmosis membrane, and belongs to the technical field of sewage treatment. The method of the invention comprises the following steps: Sewage is driven into the anaerobic acidification device for mixture with the NaOH solution. The mixed liquid enters into the MFC for converting the enriched organics to bioelectricity and then flows back to the anaerobic acidification device. A part of the mixed liquid passes through the MF membrane module to form effluent and enters into the sedimentation basin for phosphate removal and finally passes through activated carbon adsorption column, another part passes through the FO membrane module to form effluent and obtain high quality recycled water after the RO membrane processing. The method is a new coupled model of FO membrane and MFC and it provide a ternary combined technique integrating MFCs with anaerobic acidification and FO membrane. The change and accumulation of sewage to organic acids are achieved under anaerobic acid production and FO retention, the electricity generation performance of MFC is improved, and the reuse of reclaimed water is realized by separating of FO and RO membranes. Finally, the wastewater reuse and electricity generation are realized synchronously.

In one embodiment, a renewable energy generation and storage system and method is provided for storing both electrical and thermal energy that includes a forward osmosis system for drawing water across a membrane such that the water drawn across the membrane is used to dilute an osmotic ionic draw solution and the diluted osmotic ionic draw solution is used to drive a hydro-turbine; an FO-EED separation system for separating the drawn water from the ionic draw solution using renewable electrical energy and an osmotic polymer introduced in the FO-EED system during use, so that the ionic draw solution is re-concentrated by using electrical energy, such that the water from the ionic solution combines with the concentrated osmotic polymer; a coalescer configured to receive compressed CO.sub.2 to separate the water from the polymer by having the polymer absorb the compressed CO.sub.2 during use; and using thermal energy for separating the CO.sub.2 from the polymer, thereby regenerating a concentrated polymer solution.

Provided is a method for processing a feed solution, which is an organic solution containing a small amount of water, using forward osmosis under a non-heated condition to obtain a dehydrated feed solution without causing degradation or change in quality of a solute. This method is for dehydrating a feed solution containing a first organic solvent, water, and a first solute, and comprises a dehydration step for bring the feed solution and an organic draw solution containing a second organic solvent into contact with each other through a forward osmosis membrane to obtain a dehydrated feed solution that has the moisture content thereof reduced to less than 1 mass % through dehydration. In one mode, the initial moisture content of the feed solution in the dehydration step is not less than 1 mass % but less than 30 mass %, and the initial moisture content of the organic draw solution is less than the initial moisture content of the feed solution.

A draw solute for a forward osmosis membrane process, containing a compound including a structural site derived from an amine compound and a polyoxyalkylene structural site wherein two or more oxyalkylene groups are randomly bonded.

A method and system of generating electrical power or hydrogen from thermal energy is disclosed. The method includes separating, by a selectively permeable membrane, a first saline solution from a second saline solution, receiving, by the first saline solution and/or the second saline solution, thermal energy from a heat source, and mixing the first saline solution and the second saline solution in a controlled manner, capturing at least some salinity-gradient energy as electrical power as the salinity difference between the first saline solution and the second saline solution decreases. The method further includes transferring, by a heat pump, thermal energy from the first saline solution to the second saline solution, causing the salinity difference between the first saline solution and the second saline solution to increase. The method may include a process of membrane distillation, forward osmosis, evaporation, electrodialysis, and/or salt decomposition for further energy efficiency and power generation.

Methods and systems for use of switchable water, which is capable of reversibly switching between an initial ionic strength and an increased ionic strength, is described. The disclosed methods and systems can be used, for example, in distillation-free removal of water from solvents, solutes, or solutions, desalination, clay settling, viscosity switching, etc. Switching from lower to higher ionic strength is readily achieved using low energy methods such as bubbling with C0.sub.2, CS.sub.2 or COS or treatment with Bronsted acids. Switching from higher to lower ionic strength is readily achieved using low energy methods such as bubbling with air, inert gas, heating, agitating, introducing a vacuum or partial vacuum, or any combination or thereof.

A method of treating a liquid. The method comprises providing a feed liquid comprising at least one solvent and at least one solute to a first side of a membrane. A single-phase draw solution comprising at least one of an aminium salt, an amidinium salt, and a guanidinium salt is provided to a second side of the membrane. The at least one solvent is osmosed across the membrane and into the single-phase draw solution to form a diluted single-phase draw solution. At least one of CO.sub.2, CS.sub.2, and COS is removed from the diluted single-phase draw solution to form a first multiple-phase solution comprising a first liquid phase comprising the at least one solvent, and a second liquid phase comprising at least one of an amine compound, an amidine compound, and a guanidine compound. A liquid purification system is also described.