Algae harvesting and cultivating systems and methods for producing high concentrations of algae product with minimal energy. In an embodiment, a dead-end filtration system and method includes at least one tank and a plurality hollow fiber membranes positioned in the at least one tank. An algae medium is pulled through the hollow fiber membranes such that a retentate and a permeate are produced.

A mobile device for biological treatment of bioreactor-type wastewater with a submerged membrane enabling treatment of greywater and blackwater has an inlet duct for effluent to be treated and an outlet duct for treated and filtered water connected to a permeate pump. The device includes a container, the interior volume of which has a parallelepiped appearance with two large vertical lateral sides, and a membrane filter having an assembly of parallel, planar filtration membranes also with a vertical appearance. The membranes are connected to a downstream collector collecting the filtered water and connected to the outlet duct. The permeate pump ensures a transmembrane flow less than the subcritical flow. At least one diffuser of fine air bubbles is located at the base of each column. Each diffuser is connected to a regulating solenoid valve and to pump, ensuring therein an airflow greater than or equal to 10 Nm.sup.3/h per diffuser.

Disclosed are methods of treating wastewater using a membrane bioreactor and achieving a target phosphorus concentration for the membrane permeate stream. These methods include the steps of dosing a wastewater stream with a rare earth clarifying agent and passing the dosed wastewater stream through the membrane to obtain a membrane permeate stream with a permeate concentration that is less than the phosphorus concentration of the influent stream. This permeate concentration also can be equal to or less than a target phosphorus concentration. In the methods as disclosed herein, the rare earth clarifying agent can be chloride salts of one or more rare earth elements and in certain embodiments, the rare earth clarifying agent can be CeCl.sub.3 and LaCl.sub.3.

Disclosed are a slidable filtration apparatus capable of performing reciprocating motion in a filtration tank and a filtration system including the same. The filtration apparatus includes a frame and a membrane module installed in the frame, wherein the frame includes at least two horizontal linear motion members provided at an upper portion thereof.

A filtration module according to one embodiment of the present invention includes plural hollow fiber membranes held while being aligned in one direction and a pair of holding members that fix both ends of the hollow fiber membranes. In the holding members, an existence region where the hollow fiber membranes exist has a rectangular shape in a direction perpendicular to the direction in which the hollow fiber membranes are aligned. The hollow fiber membranes are arranged in a matrix in a long side direction and a short side direction of the existence region. In the existence region, a ratio of an average pitch of the hollow fiber membranes in the long side direction to an average pitch of the hollow fiber membranes in the short side direction is 1.2 or more and 2.5 or less.

A multi-stage submerged membrane distillation water treatment apparatus including: a plurality of raw water tanks arranged in multiple stages ranging from a first stage to an n-th stage and storing raw water, the raw water flowing sequentially from the first stage to the n-th stage; membrane distillation (MD) modules submerged in the respective raw water tanks and discharging a portion of the raw water as vapor; heat exchangers submerged in the respective raw water tanks and maintaining the raw water at a predetermined temperature by performing heat exchange between the raw water and vapor supplied from the respective previous-stage MD modules; a vapor generator generating and supplying high-temperature vapor to the first-stage heat exchanger; a condenser condensing vapor supplied by the n-th-stage MD module; and a raw water feeder feeding low-temperature raw water to the first-stage raw water tank via the condenser.

Provided is a method for treating a hexavalent chromium-containing aqueous solution by water treatment employing a titanium dioxide photocatalyst that is excellent in both photocatalytic activity and solid-liquid separation performance. The method according to the present disclosure includes the steps of: adding catalyst particles to the aqueous solution; reducing hexavalent chromium by irradiating the aqueous solution with light having a wavelength of 200 nanometers or more and 400 nanometers or less while stirring the catalyst particles in the aqueous solution; and stopping the stirring and separating the catalyst particles from the aqueous solution by sedimentation. Each catalyst particle is composed only of a titanium dioxide particle and a zeolite particle, the titanium dioxide particle is adsorbed on the outer surface of the zeolite particle, the zeolite particle has a silica/alumina molar ratio of 10 or more, and the catalyst particles are contained in the aqueous solution at a concentration of 0.4 grams/liter or more and 16 grams/liter or less.

A filtering membrane module and a filtering apparatus having the same, which is capable of remarkably reducing a vibration of filtering membrane module during an aeration process for a maintenance cleaning of filtering membrane, and preventing a crack from occurring in the filtering membrane module by the vibration, wherein the filtering membrane module comprises a filtering membrane; a header, to which the filtering membrane is potted, including a first lateral side and a second lateral side opposite to the first lateral side; a first coupling unit provided at the first lateral side; and a second coupling unit provided at the second lateral side.

Disclosed is an aeration unit capable of cleaning all the hollow fiber membranes in a filtering apparatus sufficiently and uniformly thereby improving the filtration efficiency and a filtering apparatus comprising the same. An aeration unit of the present invention comprises a plurality of aeration tubes parallel to each other, each of the aeration tubes comprising a first end and a second end opposite the first end; and a first common pipe in fluid communication with the aeration tubes through the first ends of the aeration tubes to provide the aeration tubes with air. The first common pipe is perpendicular to the aeration tubes. The closer to both ends of the first common pipe the aeration tubes are, the more densely the aeration tubes are arranged.

The disclosure relates to a system and method for cleaning filters, such as membrane filters. More particularly, a method and system are disclosed for retaining a plurality of small particulates, preferably in the shape of beads, which contact sludge or other despots on the membrane filters to remove unwanted debris that would otherwise form on the cleaning filters. In various embodiments, the plurality of small particulates are retained in a permeable enclosure formed of wedgewire.