Produced water from a crude oil or natural gas production process is purified using a membrane purification system for petroleum production, agricultural, commercial and domestic uses. The produced water is pretreated to remove, at least, particulates and oil from the produced water. The minimally pretreated water is then purified in a membrane purification system, that is operated at conditions such that membrane scaling is reduced or prevented. In particular, the membrane purification system is operated to maintain the turbidity of clarified water feed to the system or intermediate aqueous streams that are cascading through the membrane purification system. Ensuring that the turbidity of the reject streams generated in the membrane system are useful in achieving long membrane operating life.

Provided is a recovery method of useful resources in seawater and brine, and more particularly, a recovery method of useful resources in seawater and brine capable of improving adsorption efficiency and recovery efficiency of trace amounts of useful resources such as strontium, lithium, boron, or the like, present in brine at low cost by using a magnetic adsorbent composite and a solid-liquid separation process which uses magnetic force.

A process for the treatment of contaminated water (10) includes contacting the contaminated water with cryptocrystalline magnesite (14) thereby to remove one or more contaminants from the water. The invention extends to powdered cryptocrystalline magnesite with a particle size such that the powdered or particulate cryptocrystalline magnesite is able to pass through a 125 m particle size sieve for use in the treatment of water.

An electrodeionization device having an improved boron rejection capability compared with high-performance electrodeionization devices proposed in the related art is provided. An electrodeionization device comprising a cathode; an anode; and a plurality of cation-exchange membranes and a plurality of anion-exchange membranes, the plurality of cation-exchange membranes and the plurality of anion-exchange membranes being arranged between the cathode and the anode so as to form concentrating compartments and desalting compartments, the concentrating compartments and desalting compartments being arranged alternately, the desalting compartments being filled with an ion-exchange resin, wherein the ion-exchange resin has an average particle size of 100 to 300 ?m. Preferably, the ion-exchange resin has a uniformity coefficient of 1.1 or less.

A process and apparatus for enhanced boron removal from water. The process includes the steps of reacting potassium carbonate or ammonium carbonate with calcium borate in a stream of feed water to form a stream having calcium carbonate and potassium borate salt or ammonium borate salt. The stream having calcium carbonate and potassium borate or ammonium borate is introduced to an ion exchange vessel containing resin having methylglucamine in salt form with potassium carbonate or sodium carbonate to form borate and potassium sulfate or sodium sulfate. The resin in the ion exchange vessel is periodically regenerated.

A method for efficiently treating boron from water to be treated, an apparatus for producing pure water, and a method for producing pure water. An apparatus for removing boron includes a low-pressure reverse osmosis membrane apparatus to which is supplied water to be treated, a pH adjustment apparatus to adjust a pH of permeated water from the low-pressure reverse osmosis membrane apparatus to 5.0 to 9.0, a high-pressure reverse osmosis membrane apparatus to which is supplied the water adjusted by the pH adjustment apparatus, and an electrodeionization to which is supplied permeated water from the high-pressure reverse osmosis membrane apparatus.

There is provided a cellulose derivative that has a high amount of a chelate adsorption group introduced, has high hydrophilicity, and is capable of efficiently recovering boron.

The cellulose derivative of the present disclosure has a repeating unit represented by the following formula (1-1). In the following formula (I-1), R.sup.a is the same as or different from each other, and is a hydroxyl group or a group represented by the following formula (a). In the following formula (a), R.sup.1 represents a hydrogen atom or a methyl group. R.sup.2 represents a hydrogen atom or a hydrocarbon group optionally having a hydroxyl group. R.sup.3 represents a hydrogen atom or a hydrocarbon group. Note that at least one of all R.sup.3 contained in the cellulose derivative is the group represented by the following formula (a).

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Bioconversion processes are disclosed in which two or more biocatalysts including microorganisms or isolated enzymes that are substantially irreversibly retained in the interior of an open, porous, highly hydrophilic polymer are used in a common aqueous medium. In one exemplary embodiment, one biocatalyst produces a chemical product that is a substrate to at least one other biocatalyst. In another exemplary embodiment, the feed includes two or more substrates and one biocatalyst bioconverts at least one substrate and another biocatalyst bioconverts at least one other substrate. This aspect is particularly useful for treating water including disparate contaminants by metabolic degradation in a bioreaction zone including multiple types of biocatalysts.

The purpose of the present invention is to provide a porous molded body which is capable of adsorbing and removing low-molecular-weight organic matters or ions with high removal rate. The present invention relates to a porous molded body which is provided with: a plurality of columnar structures containing a crystalline polymer and having a (long side)/(short side) aspect ratio of 2 or more; and inorganic particles.

The present invention relates to a method for treating an aqueous liquid effluent containing calcium and carbonate ions and containing precipitation-inhibiting products, said process comprising the following successive steps:

a) providing an aqueous liquid effluent supersaturated with CaCO.sub.3 and containing precipitation-inhibiting products;
b) having the effluent obtained in step a) pass into a reactor with high solid content with a solid content maintained between 20 and 800 g/l and integrated solid-liquid separation, at a pH comprised between 8 and 9.2 allowing in a single step precipitation in situ of the aragonite polymorph of calcium carbonate and removal of the precipitation-inhibiting products;
c) recovering an aqueous liquid supernatant containing a suspended solids content of less than or equal to 0.1% by mass of the solid content in the reactor, advantageously a suspended solids content of less than 50 mg/l, the precipitation-inhibiting products being phosphonates.