The present invention generally relates to a method for separating solids from liquid in a slurry comprising solids and a liquid (e.g., an aqueous solution). More specifically, the method comprises contacting an effective amount of a high molecular weight polymeric flocculant with the slurry in a tanker truck or as the slurry is flowing to the truck, allowing the solids to settle during a settling time whereby the solids settle to the bottom of the tanker truck, and the liquid is removed from the tanker truck at a level above the settled solids. The high molecular weight polymeric flocculant can comprise repeat units derived from a cationic monomer, an anionic monomer, a nonionic monomer, or a combination thereof.

The present invention generally relates to a method for separating solids from liquid in a slurry comprising solids and a liquid (e.g., an aqueous solution). More specifically, the method comprises contacting an effective amount of a high molecular weight polymeric flocculant with the slurry in a tanker truck or as the slurry is flowing to the truck, allowing the solids to settle during a settling time whereby the solids settle to the bottom of the tanker truck, and the liquid is removed from the tanker truck at a level above the settled solids. The high molecular weight polymeric flocculant can comprise repeat units derived from a cationic monomer, an anionic monomer, a nonionic monomer, or a combination thereof.

The invention provides an efficient method to purify an aqueous solution, typically mine drainage water, especially of anions and cations present in the aqueous solution as dissolved solids, the anions and cations are removed by treatment with a positively charged extractant having at least eight carbon atoms, whereby an unstable emulsion is formed; the unstable emulsion is allowed to break into an extract phase loaded with the anions and cations, and a water phase depleted in anions and cations; a floc inherently forms in the loaded extractant phase and then the loaded extractant phase and floc are separated from the purified water and treated to remove the anions and cations as concentrated useful products; the treated aqueous phase now reduced in anion and/or cation content is also separated from the emulsion as a purified aqueous solution. The extractant phase is preferably recycled. A continuous water purification process is provided.

The invention teaches a method of efficiently dewatering a microcapsule slurry to form a water re-suspendable filter cake of microcapsules. The process comprises providing an aqueous slurry of microcapsules dispersed in an aqueous solution; adding an agglomeration agent and dispersing the agglomeration agent into the aqueous slurry; adjusting the pH to a pH level sufficient to agglomerate the dispersed microcapsules; and filtering the aqueous slurry of microcapsules by gravity, vacuum or pressure filtration to thereby form a filter cake of dewatered microcapsules. The agglomeration agent is sodium polyphosphate, sodium tetrapolyphosphate, sodium hexametaphosphate, and/or sodium tripolyphosphate; or with anionic microcapsules or coatings even alkaline earth metal salts such as magnesium chloride, calcium chloride or barium chloride, or even aluminum salt such as aluminum chloride.

The invention teaches a method of efficiently dewatering a microcapsule slurry to form a water re-suspendable filter cake of microcapsules. The process comprises providing an aqueous slurry of microcapsules dispersed in an aqueous solution; adding an agglomeration agent and dispersing the agglomeration agent into the aqueous slurry; adjusting the pH to a pH level sufficient to agglomerate the dispersed microcapsules; and filtering the aqueous slurry of microcapsules by gravity, vacuum or pressure filtration to thereby form a filter cake of dewatered microcapsules. The agglomeration agent is sodium polyphosphate, sodium tetrapolyphosphate, sodium hexametaphosphate, and/or sodium tripolyphosphate; or with anionic microcapsules or coatings even alkaline earth metal salts such as magnesium chloride, calcium chloride or barium chloride, or even aluminum salt such as aluminum chloride.

Disclosed are a flocculant for treating fracturing flowback fluid and a preparation method therefor, which relate to oilfield sewage treatment. The method includes: in parts by weight, dissolving gelatinized starch in water, adding unsaturated polyethylene glycol, unsaturated short-chain carboxylic acid, hydroxyethyl methacrylate phosphate and an initiator under a nitrogen atmosphere for reaction for 3-8 h, and after the reaction is completed, separating and purifying to obtain a product. The flocculant for treating fracturing flowback fluid is prepared by a one-pot method, and the solvent is water, so that the preparation method is simple and has better environmental protection performance; meanwhile, the flocculant not only can reduce turbidity, color and suspended matters of the flowback fluid, but also can effectively reduce COD and total iron of the flowback fluid, and also can reduce the mineralization to a certain degree. The flocculant has good biodegradability and has less impact on the environment.

Disclosed are a flocculant for treating fracturing flowback fluid and a preparation method therefor, which relate to oilfield sewage treatment. The method includes: in parts by weight, dissolving gelatinized starch in water, adding unsaturated polyethylene glycol, unsaturated short-chain carboxylic acid, hydroxyethyl methacrylate phosphate and an initiator under a nitrogen atmosphere for reaction for 3-8 h, and after the reaction is completed, separating and purifying to obtain a product. The flocculant for treating fracturing flowback fluid is prepared by a one-pot method, and the solvent is water, so that the preparation method is simple and has better environmental protection performance; meanwhile, the flocculant not only can reduce turbidity, color and suspended matters of the flowback fluid, but also can effectively reduce COD and total iron of the flowback fluid, and also can reduce the mineralization to a certain degree. The flocculant has good biodegradability and has less impact on the environment.

A method for treating water includes adding an alkyl amphocarboxylate and an organic chelating agent to the water. Furthermore, a composition includes disodium cocoamphodiacetate in an amount in the range of from 0.1 to 10.0 wt %; an organic chelating agent in an amount in the range of from 1.0 to 50.0 wt %; and water.