A purge air regulating unit for a drying device for compressed air, the purge air regulating unit being connectable to a housing in which a membrane filter, such as a bundle of hollow fiber membranes, is arranged such that a sub-flow of dried compressed air flowing out of the housing from an outlet channel can be conducted back to the hollow fiber membranes as purge air by the purge air regulating unit. A method for regulating the flow of dried compressed air flowing out of a membrane dryer back into a housing of the membrane dryer, the membrane dryer being equipped with a membrane filter, such as a bundle of hollow fiber membranes, is also provided.

A method of operating a filtration apparatus according to the present invention is a method of operating a filtration apparatus which includes one or more filtration modules provided with a plurality of hollow-fiber membranes arranged in parallel in one direction and a pair of holding members configured to fix both ends of the plurality of hollow-fiber membranes, and one or more cleaning modules configured to supply bubbles from below the filtration modules, the method including an operation step of carrying out a filtration treatment with the filtration modules, and a cleaning step of cleaning the filtration modules while stopping the filtration treatment with the filtration modules for 0.25 to 3 hours. The cleaning step is performed at intervals of 12 to 72 hours.

A membrane separation type activated sludge treatment method according to an embodiment of the present invention includes a step of performing biological treatment on waste water; and a step of performing membrane separation after the biological treatment step, wherein the membrane separation step is performed with a plurality of filtration modules including a plurality of hollow fiber membranes arranged adjacent to one another and oriented in one direction and a pair of holding members fixing both ends of the plurality of hollow fiber membranes, and a number of the filtration modules operated is changed in accordance with variations in an inflow rate of waste water in the biological treatment step.

Systems and related methods for purging air burst supply piping of accumulated water prior to delivering pulses of pressurized air to an interior of a screen intake through the air burst supply piping. The systems and methods can include a purge compressor delivering a purging air supply at a head pressure slightly above a head pressure of water in the air burst supply piping, wherein the head pressure of the water is equivalent to a depth at which the intake screen. The system and methods can also include a purge line arranged in a parallel orientation to an air burst supply line, wherein both the purge line and the air burst supply line are operably coupled to a pressurized air tank.

A filtration apparatus according to an embodiment of the present invention includes at least one filtration module including a plurality of hollow-fiber membranes arranged by being pulled in one direction and a pair of holding members that fix both ends of the plurality of hollow-fiber membranes, and at least one cleaning module that supplies air bubbles from below the filtration module. In the filtration apparatus, the filtration module has a structure in which the plurality of hollow-fiber membranes are arranged to form a curtain-like shape on the holding members each having a shape of a bar, and the holding members each have a plurality of regions in which the plurality of hollow-fiber membranes are densely arranged and which are disposed at intervals in a longitudinal direction.

In a first membrane filtration module comprises a membrane module comprising a plurality of permeable hollow membranes; a fluid distribution device adapted to removably surround at least a portion of the membranes of the membrane module, the fluid distribution device comprising a plurality of through-hole openings for distributing a fluid, and the fluid distribution device adapted to distribute a flow of fluid along a surface of the permeable hollow membranes. In a second membrane filtration device comprises a membrane module comprising a plurality of permeable hollow membranes, each of the permeable hollow membranes having a surface; and a gas distribution device: adapted to distribute gas bubbles to the surface of the permeable hollow membrane, adapted to removably surround at least a portion of the plurality of permeable hollow membranes, and defining a plurality of through openings for distributing the gas bubbles to the membranes.

A method of producing a sugar liquid derived from a cellulose-containing biomass includes (a) saccharifying a pretreated product having alignin content of not more than 8.5% obtained by pretreatment of a cellulose-containing biomass, to obtain a saccharified liquid; (b) filtering the saccharified liquid obtained in Step (a) through a microfiltration membrane to allow formation of a cake on a membrane surface in a feed side while obtaining a sugar liquid from a permeate side; and (c) collecting the cake formed on the membrane surface in Step (b) by peeling from the membrane.

A conventional media filter such as a gravity sand filter is converted into a membrane filter. The media is removed and replaced by immersed membrane modules. Transmembrane pressure is created by a static head pressure differential, without a suction pump, thereby creating a membrane gravity filter (MGF). Preferred operating parameters include transmembrane pressure of 5-20 kPa, 1-3 backwashes per day, and a flux of 10-20 L/m.sup.2/h. The membranes are dosed with chlorine or another oxidant, preferably at 700 minutes*mg/L as Cl.sub.2 equivalent per week or less. The small oxidant does is believed to provide a porous biofilm or fouling layer without substantially removing the layer. The media filter may be modified so that backwash wastewater is removed from near the bottom of the tank rather than through backwash troughs above the membrane modules. Membrane integrity testing may be done while the tank is emptied after a backwash.

The invention relates to a method for fouling reduction and/or fouling removal and/or prevention of fouling in membrane based fluid-flow processes, such as ED, RED, EDR, CDI, fuel cells, filtration, flow batteries, and a device capable of performing such methods. The method comprises the steps of: providing a dynamic membrane stack with a number of membranes, the stack capable of changing the average inter-membrane distance between two adjacent membranes with the inter-membrane distance being the distance between the membrane surfaces of two adjacent membranes; performing the membrane based fluid-flow process in a first state with the stack having a first set of average inter-membrane distances; switching the membrane based fluid-flow process between the first state and a second state wherein the stack having a second set of average inter-membrane distances different from the first set; and performing the membrane based fluid-flow process in the second state, wherein, at least in an initiating phase, fouling is removed and/or reduced and/or prevented.

The invention relates to a water treatment system (1) and a method for treating water (2) located in a water reservoir (3). The water treatment system (1) comprises a recirculation means (4) and a membrane filtration means (9) with a plurality of filter modules (10) disposed in the recirculation means (4). The water treatment system (1) particularly comprises a gas supply means (24) by which gas can be introduced into the filter modules (10) to clean the membranes of the filter modules (10) of the membrane filtration means (9) or by which gas supply means (24) gas can be introduced into the water reservoir (3) at one or more locations, periodically or when required, to circulate and mix up the water (2).