A cleaning solution for accelerated cleaning of a membrane having an enzyme and an agent having a pH that is compatible with the enzyme. The cleaning solution may additionally include one or both of a binding agent and a surfactant. Once the cleaning solution has been included in a solution that is used to contact the membrane for a defined period of time, one or both of a binding agent and a reducing agent may be added to the solution that has contacted the membrane. Optionally, one or both of increasing a pH of the solution and increasing a temperature of the solution may be used to reduce an activity of the enzyme.

A filtration system for liquid, particularly raw water, having at least one filtration module for filtering the liquid, a first inlet pipe for feeding liquid to the filtration module, a second inlet pipe for feeding liquid to the filtration module and at least one outlet pipe for discharging filtrate from the filtration module. A cleaning branch is arranged between the first inlet pipe and the second inlet pipe, and at least one dosing feeder for adding a cleaning chemical is connected to the cleaning branch. Additionally, a method for chemically rinsing such a filtration, wherein a cleaning chemical is added via a dosing feeder connected to a cleaning branch which is arranged between the first inlet pipe and the second inlet pipe.

A method for cleaning a filter membrane in which at least 2 types of cleaning water containing oxidizing agents are prepared, and the filter membrane is cleaned using the cleaning water in an ascending order of the oxidizabilities of the oxidizing agents. Moreover, an apparatus for cleaning a filter membrane of the present invention comprises a means for cleaning the filter membrane using at least 2 types of cleaning water containing oxidizing agents, and the filter membrane is cleaned using the cleaning water in an ascending order of the oxidizabilities of the oxidizing agents. The method and the apparatus for cleaning a filter membrane can efficiently remove polluting substances adhered to a filter membrane while reducing the amounts of oxidizing agents and water to be used, and can maintain the filtration performance for a long period of time.

A solution-type water treatment chemical, includes, as one, gluconic acid (salt) and a surfactant having an HLB determined by the following equation (1) satisfying the following equation (2), wherein in a relationship between concentrations of the gluconic acid (salt) and the surfactant and a molecular weight and HLB of the surfactant, the gluconic acid (salt) and the surfactant are contained such that the water treatment chemical does not form a gel or precipitate.

HLB=( inorganic value/ organic value)10(1)

Molecular weight>34.4HLB+1005(2)

A fixed or mobile water treatment system comprises a primary screening tank that filters wastewater to remove inorganic and organic pollutants from the wastewater, and includes an electro-coagulation unit that provides an electrical charge to wastewater exiting the primary screening tank, ultraviolet light and oxidation processes in one or more settling tanks that remove pollutants from the wastewater, and one or more filters that remove pollutants from the wastewater.

Systems and methods for processing produced water containing organic compounds include a processing vessel; a filtration layer including a filtration material; and a cleaning system that provides a washing solution to the filtration material during a cleaning cycle. The filtration layer is configured such that at least a portion of produced water that enters the processing vessel during a processing cycle of the processing system passes through the filtration layer before leaving the processing vessel. The filtration material is a metal compound such as a metal hydroxide or a metal oxyhydroxide that is substantially insoluble in aqueous solution. The washing solution includes a reagent capable of reducing the metal compound to a reduced compound soluble in aqueous solution while not decomposing the organic compounds. The organic compounds such as crude oil may be recovered from the filtration layer material after the cleaning cycle, and the filtration layer may be regenerated.

An electrochemical cell according to the present disclosure includes a casing provided with an inflow port and an outflow port, a bipolar membrane laminated body in which two or more bipolar membranes are laminated so as to be opposed, electrodes disposed so as to sandwich the bipolar membrane laminated body, and a first diffusion member disposed between the inflow port and the bipolar membrane laminated body, and provided with through holes communicating between the inflow port and the bipolar membrane laminated body. The first diffusion member is formed such that each of the through holes provided in a peripheral edge portion has a larger opening area than an opening area of the through holes provided in a central portion. This can uniformize a flow of water, so that water treatment can be efficiently executed.

A composition for cleaning membranes used in food processing comprising an amine oxide and an alkyl sulfate, the composition maintaining good cleaning performance whilst leaving a low residue of surfactant on the membrane that is cleaned using the composition. A method of use of the composition is also presented.

Provided is a method for producing a one-liquid stabilized hypobromous acid composition which contains substantially no bromate ions, has excellent sterilization performance, exhibits almost no corrosiveness relative to metals, and displays excellent storage stability. This method for producing the stabilized hypobromous acid composition includes a step in which a reaction is induced by adding, under an inert gas atmosphere, bromine to a mixed solution including water, an alkali hydroxide, and sulfamic acid, wherein the proportion of bromine added is not more than 25 wt % relative to the total weight of the composition.

Provided are a cleaning agent and a cleaning liquid that prevent a reduction in the rejection rate of an RO membrane which may occur when the RO membrane is cleaned and a method for cleaning an RO membrane with the cleaning liquid. The agent for cleaning an RO membrane includes a urea derivative. The urea derivative preferably includes urea (H.sub.2NCONH.sub.2) and/or biuret (H.sub.2NCONHCONH.sub.2). The cleaning liquid is an aqueous solution produced by diluting the cleaning agent. The method for cleaning an RO membrane uses the cleaning liquid. Urea and biuret have a structure analogous to amide bonds included in aromatic polyamide RO membranes, and have a strong affinity for amide bond portions. Urea and biuret adsorb onto the amide bond portions, and prevent the amide bonds from being broken by the cleaning liquid.