The present invention relates to a water treatment method including: a filtration step of feeding water to be treated to a membrane filtration device having loaded therein a porous separation membrane and performing filtration treatment to obtain filtrate; a discharging step of discharging the water to be treated in the membrane filtration device, which has been separated and concentrated by the porous separation membrane; and a cleaning step of cleaning the porous separation membrane by at least one treatment of physical cleaning and chemical cleaning, in which a cycle including a combination of the filtration step, the discharging step and the cleaning step is repeated multiple times, thereby obtaining filtrate. In each cycle, the filtration step and the discharging step are repeated multiple times, and the cleaning step is then carried out.

The method for purifying oses from hemicellulose originating from lignocellulosic biomass includes eliminating the cellulose matrix and the solid residues and/or the suspended materials from the acid hydrolysate containing oses in order to obtain a clarified hydrolysate, and subjecting the clarified hydrolysate, without adding any basic chemical reagent to increase the pH to at least one step of ultrafiltration and/or to at least one step of nanofiltration, so as to obtain a filtrate containing the majority of the pentoses and a retentate containing the species likely to precipitate under the effect of an increase in the pH. The filtrate is treated by at least one step of electrodialysis so as to recover the acid catalyst from an acid-supplemented solution, and obtain a deacidified filtrate.

The method for purifying oses from hemicellulose originating from lignocellulosic biomass includes eliminating the cellulose matrix and the solid residues and/or the suspended materials from the acid hydrolysate containing oses in order to obtain a clarified hydrolysate, and subjecting the clarified hydrolysate, without adding any basic chemical reagent to increase the pH to at least one step of ultrafiltration and/or to at least one step of nanofiltration, so as to obtain a filtrate containing the majority of the pentoses and a retentate containing the species likely to precipitate under the effect of an increase in the pH. The filtrate is treated by at least one step of electrodialysis so as to recover the acid catalyst from an acid-supplemented solution, and obtain a deacidified filtrate.

A water treatment assembly (10) and method for its operation, comprising a spiral wound hyperfiltration membrane module (12) connected to: i) a feed line (14) adapted for connection to a source of pressurized feed water, ii) a permeate line (16) adapted for connection to a dispenser of treated water and iii) a concentrate line (18) adapted for connection with a drain; wherein the assembly includes a pressurizable reservoir (22) containing weak acid cation exchange resin (25) and further includes at least one valve for selectively diverting flow of pressurized feed water along the feed line (14), through the reservoir (22) and returning to the feed line (14) prior to passing through the hyperfiltration membrane module (12).

A water treatment assembly (10) and method for its operation, comprising a spiral wound hyperfiltration membrane module (12) connected to: i) a feed line (14) adapted for connection to a source of pressurized feed water, ii) a permeate line (16) adapted for connection to a dispenser of treated water and iii) a concentrate line (18) adapted for connection with a drain; wherein the assembly includes a pressurizable reservoir (22) containing weak acid cation exchange resin (25) and further includes at least one valve for selectively diverting flow of pressurized feed water along the feed line (14), through the reservoir (22) and returning to the feed line (14) prior to passing through the hyperfiltration membrane module (12).

A system and a method for reusing waste water from a Reverse Osmosis (RO) filtering process are described, said system including: a Reverse Osmosis (RO) filtration system, from which a flow of highly alkaline waste water results; two tanks intended to receive waste water and able to alternately determine the physical and chemical properties of waste water through sensors or, and perform homogenization, chlorination and chemical treatments of said waste water; an output line which comprises a pump and connects the tanks to a reservoir; and said reservoir being able to blend the water treated by the tanks with treated chlorinated drinking water, depending on the physical and chemical properties of these volumes of water; the chlorination and chemical treatment includes addition of a hypochlorite compound, which reaction releases chlorine in the waste water and causes evaporation of at least O.sub.2 and H.sub.2 gases, reducing the alkaline pH of said waste water.

Disclosed herein is a single pass cross flow diafiltration system comprising: a filtration module having; two or more filtration segments fluidly connected in series, each having an upstream side and a downstream side; wherein each filtration segment comprises hollow fiber filter membranes, and wherein each filtration segment has a selected length; wherein the hollow fiber filter membranes of each filtration segment have a selected inner diameter; wherein the selected inner diameter of each filtration segment may be the same or different, provided that at least one selected inner diameter differs from another selected inner diameter, and provided that the two or more filtration segments are arranged such that no selected inner diameter in a given filtration segment is larger on the upstream side; one or more pumps, mounted to urge fluid flow; and one or more points of introduction of a diadiluent, each of said points of introduction being fluidly connected to an upstream filtration segment.

Disclosed herein is a single pass cross flow diafiltration system comprising: a filtration module having; two or more filtration segments fluidly connected in series, each having an upstream side and a downstream side; wherein each filtration segment comprises hollow fiber filter membranes, and wherein each filtration segment has a selected length; wherein the hollow fiber filter membranes of each filtration segment have a selected inner diameter; wherein the selected inner diameter of each filtration segment may be the same or different, provided that at least one selected inner diameter differs from another selected inner diameter, and provided that the two or more filtration segments are arranged such that no selected inner diameter in a given filtration segment is larger on the upstream side; one or more pumps, mounted to urge fluid flow; and one or more points of introduction of a diadiluent, each of said points of introduction being fluidly connected to an upstream filtration segment.

A nonpowered mixing and coagulation basin is provided, which generates turbulences of at least two kinds inside the mixing and coagulation basin to which the raw water flows so that foreign matters contained in the raw water come into contact with each other while circulating by a water flow to be coagulated into a predetermined size, and a dissolved air floatation device using the same. The nonpowered mixing and coagulation basin has multiple stages with different packing materials and packing densities to form turbulent flows inside the raw water and control a flow speed, thereby uniformly mixing raw water and coagulant to enhance coagulation efficiency. The nonpowered mixing and coagulation basin simultaneously carries out mixing and coagulation at the front end part of the water treatment system, reduces equipment expenses by having no electric motor and agitator, and reduces power consumption because it does not use any power unit.

A nonpowered mixing and coagulation basin is provided, which generates turbulences of at least two kinds inside the mixing and coagulation basin to which the raw water flows so that foreign matters contained in the raw water come into contact with each other while circulating by a water flow to be coagulated into a predetermined size, and a dissolved air floatation device using the same. The nonpowered mixing and coagulation basin has multiple stages with different packing materials and packing densities to form turbulent flows inside the raw water and control a flow speed, thereby uniformly mixing raw water and coagulant to enhance coagulation efficiency. The nonpowered mixing and coagulation basin simultaneously carries out mixing and coagulation at the front end part of the water treatment system, reduces equipment expenses by having no electric motor and agitator, and reduces power consumption because it does not use any power unit.