A method of cross-flow filtering wastewater from a diagnostic apparatus or a laboratory analyser, wherein the wastewater comprises nanoparticles and/or microparticles, and the wastewater is streaming in a laminar flow across a surface of a filter membrane, the method comprising: (a) streaming the wastewater across the surface of the filter membrane with a flow rate, so that the flow of the wastewater is a laminar flow with a Reynolds number (Re) of smaller than 500; (b) streaming the wastewater in pulse cycles across the surface of the filter membrane, wherein each pulse cycle comprises one active phase in which the wastewater is under a duty pressure and one inactive phase in which the wastewater is under an inactive pressure, wherein the inactive pressure is no more than 10% of the duty pressure and the active phases have a duration of greater than 50% of the corresponding pulse cycles; and (c) separating the nanoparticles and/or microparticles from the wastewater when the wastewater passes through the filter membrane. Also described is a cross-flow filtration system configured for performing the method.

Disclosed herein are apparatuses and methods for semi-permeable membrane cleaning. Specifically, a pressure retarded osmosis (PRO) process redirects raw solution and fluid streams in such a way as to cause periodic changes of the process from PRO to reverse osmosis (RO) for removing fouling. Further disclosed is applying a pulsed-flow regime in the fluid stream, thereby causing increased shearing force for enhanced foulant evacuation. Additionally, a backward wash may be provided by injection of additional solution such that net driving pressure becomes RO as opposed to PRO, thereby providing a backward flow from a first side of the membrane to a second side. Further disclosed are phased operations that resolve the issue of self-extinguishing PRO, thereby providing energy savings and/or PRO process optimization by, for instance, (1) utilizing osmotic pressure for circulation, (2) variation in POp gauge pressure, and/or (3) variation of the ratio of Additional Solution to Draw Solution.

A method for cleaning a cross-flow filter (20), comprising the steps of: A) providing a cross-flow filter (20), wherein the cross-flow filter (20) comprises a filter membrane (21) and is configured to remove a liquid permeate stream and the filter membrane (21) comprises a first side facing the permeate stream and a second side opposite the first side, the second side facing the feed stream, and wherein at least some of the deposits (1010) to be removed are located on the second side of the filter membrane (21); B) applying a back-flushing liquid stream through the filter membrane (21). Prior to applying the back-flushing liquid stream in Step B), permeate located on the first side of the filter membrane (21) is at least partially displaced from the first side of the filter membrane (21) by a gas, wherein the gas that is in contact with the back-flushing liquid stream has a pressure of >1 bar at least during Step B). The applying of the back-flushing liquid stream in Step B) occurs in such a way that the pressure pulses.

The present invention provides methods and apparatus for cleaning and sanitizing potable water devices/appliances by recirculating and pulsing a rejuvenation solution through the device/appliance using a portable apparatus comprising a mechanical pump fluidly connected to the device/appliance.

A method of cleaning a membrane surface immersed in a liquid medium with a fluid flow, including the steps of providing a randomly generated intermittent or pulsed fluid flow along the membrane surface to dislodge fouling materials therefrom. A membrane module is also disclosed comprising a plurality of porous membranes (6) or a set of membrane modules (5) and a device (11) for providing a generally randomly generated, pulsed fluid flow such that, in use, said fluid flow moves past the surfaces of said membranes (6) to dislodge fouling materials therefrom.

A method of separating heavy water from normal through application of acoustic pressure shock waves to a fluid including heavy water and normal water and recovering separated normal water.

A method of desalinating water through application of acoustic pressure shock waves to a slush to separate ice crystals from brine and recovering desalinated water from the separated ice crystals.

Acoustic pressure shock waves are applied to a membrane in a fluid to prevent attachment of or dislodge biological or solid matter for membrane cleaning or desalination with a membrane.

A method of cleaning a membrane surface immersed in a liquid medium with a fluid flow, including the steps of providing a randomly generated intermittent or pulsed fluid flow along the membrane surface to dislodge fouling materials therefrom. A membrane module is also disclosed comprising a plurality of porous membranes (6) or a set of membrane modules (5) and a device (11) for providing a generally randomly generated, pulsed fluid flow such that, in use, said fluid flow moves past the surfaces of said membranes (6) to dislodge fouling materials therefrom.

A method of treating fluids, including for recovery of water apart from impurities or undesired matter, utilizes application of shock waves to the fluids.