A system and method for generating power from waste heat, the system including (1) a forward osmosis module having an FO membrane a water inlet, a water outlet, a draw solution solute inlet and a diluted draw solution outlet; (2) a hydro-turbine using the diluted draw solution for generating power; (3) a CO.sub.2 absorption reactor to permit the introduction of compressed CO.sub.2 into the diluted draw solution to cause substantial separation of draw solution solute from the water, which water can be processed for subsequent recycling to the FO module, the CO.sub.2 absorption reactor configured to discharge a mixture of separate draw solution solute and absorbed CO.sub.2; and (4) a heat exchanger for transferring waste heat from an incoming heated fluid to the mixture of draw solution solute and CO.sub.2.

A water treatment method according to the present invention is a water treatment method in which oil is membrane-separated from water to be treated containing the oil and ferrous ions, the water treatment method including an oxidation step of oxidizing the ferrous ions in the water to be treated, and a filtration step of membrane-filtering the water to be treated after the oxidation step. In the oxidation step, a pH of the water to be treated is adjusted to 6 to 9, and an oxidation-reduction potential of the water to be treated is adjusted to 450 to 750 mV.

A water treatment method according to the present invention is a water treatment method in which oil is membrane-separated from water to be treated containing the oil and ferrous ions, the water treatment method including an oxidation step of oxidizing the ferrous ions in the water to be treated, and a filtration step of membrane-filtering the water to be treated after the oxidation step. In the oxidation step, a pH of the water to be treated is adjusted to 6 to 9, and an oxidation-reduction potential of the water to be treated is adjusted to 450 to 750 mV.

Separation processes using osmotically driven membrane systems are disclosed generally involving the extraction of solvent from a first solution to concentrate a solute by using a second concentrated solution to draw the solvent from the first solution across a semi-permeable membrane. Pre-treatment and post-treatment may also enhance the osmotically driven membrane processes.

Separation processes using osmotically driven membrane systems are disclosed generally involving the extraction of solvent from a first solution to concentrate a solute by using a second concentrated solution to draw the solvent from the first solution across a semi-permeable membrane. Pre-treatment and post-treatment may also enhance the osmotically driven membrane processes.

An object of the present invention is to provide a water treatment system in which explosions can be prevented even when filtering water to be treated that is able to generate flammable gas. A water treatment system according to an embodiment of the present invention includes a water-to-be-treated tank which stores water to be treated, a crossflow-type filtration membrane module which filters the water to be treated, a supply passage through which the water to be treated is supplied to the filtration membrane module from the water-to-be-treated tank by using a supply pump, and a recirculation passage through which the water to be treated is recirculated from the filtration membrane module to the water-to-be-treated tank. The supply passage is provided with an aspirator which mixes a gas with the supplied water to be treated, the gas being recirculated through the recirculation passage to the water-to-be-treated tank together with the water to be treated. The water-to-be-treated tank has an upper space provided above the liquid surface of the stored water to be treated, the upper space being hermetically filled with an inert gas. The water-to-be-treated tank is further provided with a gas transport passage through which the inert gas is supplied from the upper space to the aspirator.

A biological reactor system treats concentrated contaminated water with a combination of upflow and downflow bioreactors that are downstream from a reverse osmosis or other concentrator. The system may have a fail safe configuration where flush water may be introduced to the reactors in the event of a power failure or when taking the reactors offline. Many reverse osmosis systems introduce antiscalant treatments upstream so that the reverse osmosis filters do not scale. However, such treatments result in superconcentrated conditions of the antiscalants in the contaminated water processed by the bioreactors. A flushing system may deconcentrate the bioreactors to prevent the antiscalants from precipitating and fouling the bioreactors.

A biological reactor system treats concentrated contaminated water with a combination of upflow and downflow bioreactors that are downstream from a reverse osmosis or other concentrator. The system may have a fail safe configuration where flush water may be introduced to the reactors in the event of a power failure or when taking the reactors offline. Many reverse osmosis systems introduce antiscalant treatments upstream so that the reverse osmosis filters do not scale. However, such treatments result in superconcentrated conditions of the antiscalants in the contaminated water processed by the bioreactors. A flushing system may deconcentrate the bioreactors to prevent the antiscalants from precipitating and fouling the bioreactors.

The present disclosure is directed toward membrane biofilm reactors primarily comprising microorganisms that produce chemical fuel products or precursors thereof. Reactors of the present disclosure can primarily comprise acetogens, a methanotrophs, and/or Methanosarcina acetivorans.

The present invention relates to an integrated electrochemical lithium extraction process to directly produce lithium hydroxide from geothermal brine. The process integrates electrochemical silica removal, selective uptake and release of lithium using an intercalation material, and electro-driven generation of hydroxy (OH.sup.) ions.