Abstract: In a process and apparatus for treating produced water, for example for re-use in an oil or bitumen extraction operation of for treating frac water, the produced water flows through a series of treatment units. A portion of the produced water may by-pass one or more of the treatment units but the by-pass portion may be such that the treated water is still acceptable, for example for discharge or reuse. Concentrations of oil and grease, organic carbon, silica, pH or related parameters in the produced water may be monitored and used to control the process or apparatus. Control of the process may involve one or more of altering a by-pass portion, altering the addition of chemicals, and altering the operation of a unit process. The process may be controlled to respond to upset conditions, or such that the concentration of one or more limiting contaminants is near, but not over, a specified maximum for re-use or discharge.

Abstract: A new method for removing ammonia nitrogen in coking wastewater is disclosed in this invention. It comprises steps as follow: introducing coking wastewater into a reaction pool into which magnesium and phosphate are added; adding sodium hydroxide to regulate the PH of the mixture around 9.0-10.5; separating the supernatant and the precipitate after proper agitation and natural precipitation; dehydrating the precipitate and then adding alkaline fly ash, water to the dehydrated precipitate and stirring the mixture; decomposing the mixture with heating and absorbing the ammonia gas thereof produced with acidic solution. In consideration of high concentration of ammonia nitrogen in coking wastewater, this invention aims at quick and efficient treatment. The concentration of ammonia nitrogen in treated water meets the highest discharge standard stipulated in [China National] Integrated Wastewater Discharge Standard (GB8978-96).

Abstract: A fluid treatment device and method is proposed for the treatment of a fluid that has components to be separated, such as tailings. The fluid treatment device in one embodiment comprises a motive pump connected to drive fluid to be treated along a conduit through a restriction forming a nozzle into a mixing chamber and thence to a discharge. A port, which may be controlled by a valve, admits gas into an initial portion of the mixing chamber. The motive pump, nozzle, gas port and mixing chamber together form a phase separator. Multiple phase separators may be connected together in series. The mixing chamber may have constant diameter and a length to diameter ratio of 20:1 or 60:1 or more. The conduit terminates in a discharge. The discharge may supply the treated fluid to a secondary separation device such as a flotation cell. Solids and liquids may be taken off the flotation cell for disposal, further processing or delivery into a sales line.

Abstract: A system and method for the treatment of wastewater. In one aspect, the invention can be a method of treating wastewater comprising: a) flowing the wastewater along an axis; b) injecting a polymer into the wastewater at multiple injection points to flocculate suspended solids within the wastewater, the multiple injection points arranged in a circumferentially spaced apart manner about the axis; and c) removing the flocculated suspended solids from the wastewater to form a treated water. In another aspect, the invention can be a system for flocculating suspended solids in wastewater comprising: a conduit through which wastewater flows along an axis; a plurality of nozzles operably coupled to a source of a first polymer; and the plurality of nozzles arranged in a circumferentially spaced apart manner about the axis, the plurality of nozzles operably coupled to the conduit to inject the first polymer into the wastewater flowing through the conduit.

Abstract: Methods for removing one or more contaminants from an aqueous stream comprising: adding one or more hydraulic binders and one or more promoters to the aqueous stream, and separating the contaminants from the aqueous stream are provided. The methods may be used for removing contaminants that are arsenic-based, selenium-based, cadmium-based, zinc-based, mercury-based, iron-based, chromium-based and/or phosphate-based.

Abstract: A system and method for the treatment of wastewater. In one aspect, the invention can be a method of treating wastewater comprising: a) introducing wastewater having a first turbidity level into a wastewater treatment system; b) injecting an aqueous polymer mixture into the wastewater to flocculate suspended solids within the wastewater; c) removing the flocculated suspended solids from the wastewater to form a treated water having a second turbidity, the second turbidity being lower than the first turbidity; and wherein the aqueous polymer mixture of step b) is formed by introducing a raw polymer into a re-circulated portion of the treated water.

Abstract: A method for membrane fluid filtration and remediation is described herein. The method can include flowing a slurry into a scalping shaker and separating a first particulate from the slurry, forming a first effluent. Free oil can be removed from the first effluent using a first weir, forming a cleaned effluent that can be discharged using a second weir. The cleaned effluent can flow through an absorbent material disposed over a circulation tank for removing more free oil from the cleaned effluent, forming a circulation effluent. A sludge can settle from the circulation effluent within the circulation tank, forming a cleaned circulation stream. The cleaned circulation stream can flow through an ultra-filtration membrane which can separate the cleaned circulation stream, forming a clean permeate and a dirty concentrate. The dirty concentrate can flow back to the circulation tank for further processing.

Abstract: A method of treating contaminated water effluent from a well drilling operation. The method comprises decomposing organic contaminants in the effluent by bubbling a gas containing ozone through the effluent; adding a coagulant to increase the particle size of solid particles contained in the effluent; adding a flocculant to increase the particle size of solid particles contained in the effluent, thereby forming flocs suspended in the effluent; and filtering the flocs from the effluent to produce a filtrate and flocculated solids. The method may further comprise adding the coagulant into a stream of effluent flowing within a first conduit under controlled shear conditions, and adding the flocculant into a stream of effluent containing pin flocs flowing within a second conduit under controlled shear conditions. The method may further comprise delivering the effluent containing the suspended flocs into a filter through a conduit floating in the effluent contained in the filter.

Abstract: Nanoscale additives and methodology for their use during polymer-aided sludge dewatering to increase the dewatering efficiency compared to traditionally used polymer-only dewatering processes. The nanoscale additive increases the percent solids in the dewatered cake compared to polymer-only treatment. When the nanoscale additives are added, the centrifugal force (shear) required to obtain high percent solids can be significantly reduced and the optimum polymer dose required for effective dewatering is also significantly reduced.

Abstract: A river water utilizing flue gas desulfurization system 10 according to an embodiment of the present invention includes: a pre-treatment facility 13 that removes humic substances in river water 11 to produce makeup water 12; and a desulfurization apparatus 17 that brings sulfur content in flue gas 15 into contact with limestone gypsum slurry 16 in an apparatus body 14. The pre-treatment facility 13 includes a flocculant mixing basin 22 in which a flocculant 21 is added to the river water 11 to flocculate and remove the humic substances contained in the river water 11; and an activated carbon absorption unit 23 in which the humic substances contained in the river water 11 are absorbed and removed by way of activated carbon.

Abstract: Precipitation vessel for precipitation of flocculants from lubricating oil includes a hollow housing having an interior volume capable of containing oil; an entry port capable of allowing oil to enter into the interior volume; a stirrer capable of stirring contained oil; a heater capable of heating the contained oil; a product exit port capable of allowing oil to exit the interior volume; an upper exterior access port; and a lower exterior access port. Contaminated lubricating oil can be cleaned from solid particulates by a method of providing a vessel for containing oil; providing contaminated lubricating oil to the vessel; contacting the contaminated lubricating oil with a coagulant, and, maintaining the resulting mixture at a mildly elevated temperature throughout the vessel, inducing flocculation of solid particles and settlement of flocculated particles under low thermo-current, if not thermo-current-free, conditions; and drawing off lubricating oil cleaned from settled flocculated solid particles.

Abstract: The invention provides a method of efficiently removing selenium from water. The method involves: adding an oxidant to the liquid, adjusting the liquid's pH to below 7.5, adding ferric salt in an amount such that less than a quarter of selenium in the liquid precipitates and adding a poly dithiocarbamate material to the liquid in an amount such that the amount of poly dithiocarbamate material (in ppm) is greater than the amount of ferric salt (in ppm). This method removes far more selenium than previous methods, and does it using a smaller amount of expensive chemicals. Moreover this method makes it far more likely to achieve cost effective compliance with the ever-increasing environmental standards for selenium in water.

Abstract: The present invention relates to a method for making pure salt comprises recapturing post-drilling flowback water from hydro-fracturing; removing oil from the flowback water; filtering the flowback water using an ultra filter with a pore size of about 0.1 microns or less to remove solid particulates and large organic molecules, such as benzene, ethylbenzene, toluene, and xylene, from the water; concentrating the flowback water to produce a brine that contains from about 15 wt % to about 40 wt % of salt relative to the total weight of the flowback brine; performing one or more chemical precipitation process using an effective amount of reagents to precipitate out the desired high quality commercial products, such as, barium sulfate, strontium carbonate, calcium carbonate; and crystallizing the chemically treated and concentrated flowback brine to produce greater than 99.5% pure salt products, such as sodium and calcium chloride.

Abstract: As population density increases, the transportation of hazardous chemicals, including acids and disinfectants, lead to an increased incidence of spills while the consequences of spills become more serious. While solutions of halide acids, hypohalites and halites are safer disinfectants for transportation, handling, storage and use than traditional gaseous chlorine, the manufacturing cost of these disinfectants has here-to-fore limited their use. Economical processes are presented for the manufacture of O2, halogen oxides, halide acids, hypohalites, and halates; as well as polynucleate metal compounds, metal hydroxides and calcium sulfate hydrate (gypsum). The instant invention presents methods and processes that incorporate the use of sulfur. This is while environmental regulators, such as the US EPA, require an increased removal of sulfur from hydrocarbon fuels, thereby creating an abundance of sulfur, such that the refining industry is in need of a way to dispose of said abundance of sulfur.

Abstract: The present invention is a system and method for treating a wastewater stream to produce an effluent having an acceptable level of turbidity. The invention comprises a controller operatively coupled to at least one turbidity meter for monitoring turbidity of the effluent stream. A plurality of chemical treatment additive pumps are provided for providing a plurality of additives to the wastewater stream. Furthermore, a method of sequentially testing the amount of each additive required to produce an effluent stream having an acceptable turbidity is disclosed.

Abstract: The invention provides methods and compositions for improving the production of alumina. The invention involves adding a product containing one or more polysaccharides to liquor within the fluid circuit of the production process, where one of the polysaccharides is scieroglucan. The use of scleroglucan can impart a number of advantages including at least some of: greater flocculation effectiveness, increasing the maximum effective dosage, faster settling rate. The production process can be a Bayer process.

Abstract: A method for removal of ammonia from a polluted medium avoids the disadvantages related to the chemical-physical properties of an ammonium-containing salt (MAP). The method has improved technical and economical operational parameters and produces a reusable and environmentally friendly nitrogen fertilizer. All chemical processes and mechanical steps of the method are carried out in one single container, with the different steps divided into time phases. The chemical products are prevented from transportation between compartments and contact with pumps and pipes. Only liquids without precipitates are in contact with these elements. The method is applicable to ammonia-containing water from leachate, wastewater, the food industry, and agriculture.

Abstract: Disclosed is an economical process for the purification of water containing soluble and sparingly soluble inorganic compounds using single-stage or two-stage membrane processes that integrate membrane water purification with chemical precipitation softening and residual hardness and silica removal from the membrane concentrates using ion exchange resins and silica sequestering media, respectively.

Abstract: A process for reducing the amount of magnesium in a lithium-containing brine by adding an aqueous solution of KCl to the brine to precipitate at least some of the magnesium as carnallite salt is disclosed. Lithium salts prepared using this magnesium removal process are also disclosed.

Abstract: The present invention relates to processes for reducing or eliminating the amount of hydrazine from a hydroxylamine-free base containing hydrazine by treating said hydroxylamine-free base with a scavenger agent, and to the hydroxylamine-free base thereby obtained, as well as to its use for producing microdispersions containing a hydroxamated polymer for use as a flocculant in the Bayer process.

Abstract: A system and method of reducing ammonia emissions. The system and method include a facility having a waste storage compartment below a floor comprised of slats with openings therebetween. A plurality of injection pipes are attached to a bottom surface of the slats. Each of the plurality of injection pipes includes a plurality of precipitation nozzles.

Abstract: The invention relates to a polymer comprising structural units of formula and formula wherein R1, R2, R5 and R6 are independently hydrogen, a methyl group, or —COOH, only one of R1 and R2 or R5 and R6 is —COOH; R3 and R7 are independently hydrogen, or a methyl group; R4 is —COOH, —CONH2 or —OH, when R4 is —OH, R1, R2 and R3 are respectively hydrogen; and R8 is —COO, —CONH, or —O—, when R8 is —O—, R5, R6 and R7 are respectively hydrogen. Methods for preparing and using the polymer are also described herein.

Abstract: A method of removing phosphonates from water includes directing the water into a first settling zone. The water is then directed to a membrane filtration zone and is filtered therein to produce a concentrate containing phosphonates. The concentrate containing phosphonates is then contacted with sludge such that at least some of the phosphonates in the concentrate are adsorbed onto the sludge. Flocculant is added to the sludge and the concentrate to form a floc-mixture which is directed to a second settling zone to form treated concentrate.

Abstract: A method for removing components from an aqueous medium is described. The method includes dispensing a formulation comprising one or more of zinc chloride, calcium chloride, zirconium acetate and zirconium oxychloride to an aqueous medium. The method includes allowing the formation of floccules in the aqueous medium, wherein the floccules contain the component to be removed. The method includes separating the floccules from the aqueous medium to remove the component.

Abstract: A process for improving inline mineral slurries treatment comprises successively: providing an in-line flow of slurries in a main stream; introducing at least one polymer into the main stream through at least one polymer injection point to cause dispersion of the polymer and to start the coagulation and/or the flocculation of slurries to produce treated slurries; and splitting the main stream containing treated slurries into two streams respectively: a discharge stream which directly transfers a part of treated slurries to the deposit area, and a split stream which reintroduces the other part of treated slurries into the main stream through at least a reinjection point in a location prior to the at least one polymer injection point.

Abstract: Systems, compositions, and methods for dewatering and/or increasing a mechanical strength of mine tailings. These systems, compositions, and methods may include combining mine tailings with wicking fibers to form a composite mine tailings mixture. The wicking fibers may provide a conduit for the removal of fluid from the composite mine tailings mixture. The composite mine tailings mixture further may include a binder that may decrease repulsive forces among fine particles that comprise the mine tailings and/or increase attractive forces among the fine particles, leading to a separation of the fine particles from at least a portion of the fluid contained within the composite mine tailings mixture. The composite mine tailings mixture may be placed in a storage or dewatering area as a composite mine tailings mixture deposit, which may include internal structure, such as layers of the composite mine tailings mixture and/or long-range orientation of the wicking fibers contained therein.

Abstract: The suspended solids content of a Bayer process stream is reduced by contacting the stream with silicon-containing polymers.

Abstract: A method and an apparatus for treating selenium-containing wastewater, in which wastewater containing hexavalent selenium is subjected to reduction treatment, selenium can be effectively removed at a small amount of metal leached, and, preferably, sludge produced during treatment is white, thereby facilitating the disposal of the sludge. The selenium-containing wastewater is brought into contact with an alloy or a mixture of metallic titanium and a first metal other than metallic titanium to partially leach the first metal, thereby subjecting selenium in the wastewater to reduction treatment.

Abstract: A method of purifying arsenic contaminated water is disclosed. The method comprises of adding to the arsenic contaminated water predetermined quantities of iron and alkali; and passing the water so obtained through a filter medium including rice husk ash. A device for purification of arsenic contaminated water is also disclosed.

Abstract: A method of capturing and storing excess carbon dioxide (CO2) includes seeding melt water lakes formed on glacial masses with metal hydroxides. The excess CO2 is then stored as a precipitate from the seed of CO2 and metal hydroxides. Further, a method to apply nutrient minerals directly to pack-ice and open water promotes carbon sequestration by chlorophyll and subsequently phytoplankton, oxygen, and zooplankton.

Abstract: The present invention relates to a method for making pure salt comprises recapturing post-drilling flowback water from hydro-fracturing; removing oil from the flowback water; filtering the flowback water using an ultra filter with a pore size of about 0.1 microns or less to remove solid particulates and large organic molecules, such as benzene, ethylbenzene, toluene, and xylene, from the water; concentrating the flowback water to produce a brine that contains from about 15 wt % to about 40 wt % of salt relative to the total weight of the flowback brine; performing one or more chemical precipitation process using an effective amount of reagents to precipitate out the desired high quality commercial products, such as, barium sulfate, strontium carbonate, calcium carbonate; and crystallizing the chemically treated and concentrated flowback brine to produce greater than 99.5% pure salt products, such as sodium and calcium chloride.

Abstract: The present invention relates to a treatment installation of aqueous fluid, in particular to ensure elimination of organic micropollutants and natural organic matter, comprising a single reactor (10) for treatment of aqueous fluid by contact with a fluidised bed of coagulated and flocculated powdered activated carbon, operating in ascending flow, said reactor being equipped with injection means of new powdered activated carbon, coagulant and polymer, arranged to define three distinct operating zones in the reactor: a first arranged zone (A) at the base of the reactor to ensure intake and homogeneous distribution of the aqueous fluid pre-treated by contact with coagulant and polymer, a second zone, surmounting the first, constituted by the fluidised bed of coagulated and flocculated powdered activated carbon (B), and a third zone (C), arranged in the top part of the reactor for separation and recovery of the purified aqueous liquid.

Abstract: A process for producing a purified nickel hydroxide precipitate from a nickel-containing leach solution with impurities including one or more of the following: manganese, copper, zinc, iron and/or cobalt, so that the purified nickel hydroxide is suitable for pelletization with iron-containing ores and/or stainless steel production, includes treating the leach solution with a base to form a slurry of mixed hydroxide precipitate and low-nickel barren solution, thickening the slurry to form filter cake, washing the filter cake and contacting it with acid to dissolve nickel and other metals to produce a concentrated nickel-containing solution, subjecting the concentrated nickel-containing solution to solvent extraction with an organic acid extractant to remove metals other than nickel from the nickel-containing solution and form a solvent extraction raffinate of purified nickel solution and treating the solvent extraction raffinate with a base to precipitate the purified nickel hydroxide precipitate.

Abstract: Water from underground and other sources of water are brackish and not suitable for human consumption. Naturally present dissolved chemicals in water make it brackish. The precipitants and dissolved chemicals need to be separated from water to make it consumable. A combination of aeration systems, filtration systems, crystallizers and hydrophobic membrane carrying filter are used to desalinate the brackish water. Solar energy and ceramic filters are used as add on to existing technology. Various heat exchange apparatus are used for energy conservation and efficient processing of water in a feasible way. The disclosure enables to purify water and provide a useful technology to eradicate water scarcity.

Abstract: Methods for more efficiently carrying out various operations through the use of pressure transfer between streams. The methods are applicable for use in conjunction with a wide range of processes including precipitation reactors (19), subterranean space (49) temperature control systems and exothermic chemical processors (71). Rotary isobaric pressure exchange units (29,55,81) are preferably employed.

Abstract: The invention relates to a method of controlling the solubility of granular material by treating a precipitate comprising iron(II)sulphate monohydrate originating from titanium dioxide production, in which method the reaction temperature is allowed to increase at the most to a temperature of 120° C., to a plant for treating a precipitate comprising iron(II)sulphate monohydrate, to a product and its uses. A typical method according to the invention comprises the steps of mixing water to the reaction mixture in the said mixing apparatus, and keeping the amount of neutralizing agent sufficient to give a pH value from 1.5 to 4, preferably from 1.5 to 3, to the end product in order to obtain a granular material having a high soluble iron(II) content or keeping the amount of neutralizing agent sufficient to give a pH value ?9 to the end product in order to obtain a granular material having a low solubility.

Abstract: Substitution of a single Ga-atom or single Ge-atom (GaAl12 and GeAl12 respectively) into the center of an aluminum Keggin polycation (Al13) produces an optimal water-treatment product for neutralization and coagulation of anionic contaminants in water. GaAl12 consistently shows ˜1 order of magnitude increase in pathogen reduction, compared to Al13. At a concentration of 2 ppm, GaAl12 performs equivalently to 40 ppm alum, removing ˜90% of the dissolved organic material. The substituted GaAl12 product also offers extended shelf-life and consistent performance. We also synthesized a related polyaluminum chloride compound made of pre-hydrolyzed dissolved alumina clusters of [GaO4Al12(OH)24(H2O)12]7+.

Abstract: A method of removing mineral hardness of water comprises selecting a mineral hardness solubility constant modifier capable of at least partially precipitating insoluble mineral hardness material from water containing mineral hardness. A pressurized flow of the water containing mineral hardness is generated. The mineral hardness solubility constant modifier is added to the pressurized flow of water containing mineral hardness to form water bearing precipitate mineral hardness. The water bearing precipitate mineral hardness is filtered to at least partially remove the precipitated insoluble mineral hardness material from the water bearing precipitate mineral hardness to form post-filtered water.

Abstract: A method of reducing or preventing the amount of iron sludge or precipitate that forms as a result of the recovery of silver from chemical solutions, such as a standard photographic solution. The method generally involves the introduction of a source of a conjugate organic base, such as a weak organic acid like citric acid or a salt of the conjugate organic base like a citrate salt, to the chemical fluid either before or during the silver recovery process. Preferably the source of conjugate organic base is introduced by combining it with a binder to form a time release cake or placing it in a container that has a semipermeable membrane that maintains the concentration of the conjugate organic base in the chemical fluid from about 0.2 to about 78 milimolar over a period of time.

Abstract: Sulfate anions and divalent metal ions, such as magnesium, strontium and barium, in water are removed by treating the water with polyaluminum chloride, usually together with lime, to form ettringite and similar crystalline species which are readily removable by settling, filtration and the like. Iron is also removed by oxidation in a variation of the process. The process is particularly useful for treating aqueous solutions used in well treatment, where flowback fluids can provide some of the divalent metal ions necessary to form the ettringite-like materials, thus reducing the amount of lime otherwise necessary and further facilitating recycling of the fluid.

Abstract: Disclosed are methods of removing particulate matter from potash tailings fluid. The invention includes providing an activating material capable of being affixed to the particulate matter, affixing the activating material to the particulate matter to form an activated particle, providing an anchor particle and providing a tethering material capable of being affixed to the anchor particle; and attaching the tethering material to the anchor particle and the activated particle to form a removable complex in the potash tailings fluid.

Abstract: A water or wastewater treatment system to reduce phosphorus or other pollutant concentrations in water or wastewater may include an optional primary treatment stage in fluid communication with a biological secondary treatment stage. The secondary treatment stage may, in turn, be fluidly connected with a tertiary treatment stage, which may include a chemical treatment portion for reducing phosphorus or other pollutants to desired levels. The precipitated phosphorus and other solids or sludge produced from the chemical treatment portion may be recycled upstream for reuse in the primary, secondary, and/or tertiary treatment stages. Such recycle may reduce the amount of added chemicals required in the tertiary treatment stage to phosphorus or other pollutants to desired amounts.

Abstract: A method and system for purifying production water obtained from oil and gas operations so that the purified water need not be disposed of by forced injection back into the geological formation but can be put to a beneficial use such as agriculture, irrigation, industrial or municipal or potable applications. The production water is treated in a ceramic microfilter after it has been pretreated (preferably by aeration and with a walnut shell filter) to remove volatile hydrocarbons and heavier oils, such as paraffins and asphaltenes, that could foul the ceramic filter. The permeate from the ceramic microfiltration can then be treated with activated charcoal or otherwise treated to meet the specific requirements for the intended beneficial use.

Abstract: The present invention provides useful biodegradable and environmentally friendly cost effective methods for oil recovery and reclamation from oil spills and chemical spills. More particularly, methods to recover and reclaim hydrocarbons or hydrophobic substances in an aqueous environment.

Abstract: Embodiments are provided for removing a variety of contaminants using both rare earth and non-rare earth-containing treatment elements.

Abstract: Contemplated wastewater treatment plants and processes comprise a unit in which a silicate-containing waste stream is combined with an alkaline process stream to so form a pH-controlled intermediate that is then fed to a reactor in which carbonization effects precipitation of the silicate. Following a particle growth step in the reaction vessel that renders the precipitate suitable for filtration, the so produced silicon dioxide can be safely disposed of in a landfill while the liquid can be discharged or sent to a zero liquid discharge pond to precipitate sodium carbonates.

Abstract: A solubilized reagent for treating and binding heavy metals and method of producing and process of using the same. The solubilized reagent includes an isolated supernatant of a slurry or a saturated or supersaturated solution of alkali metal/alkaline earth metal carbonate, alkali metal/alkaline earth metal sulfide, and triple super phosphate.

Abstract: A novel use of delayed reactivity partly prehydrated lime (“DRQL”), which is comprised of 40 to 98% by weight of CaO and of 60 to 2% by weight of Ca(OH)2, preferably of 80 to 92% by weight of CaO and of 20 to 8% by weight of Ca(OH)2, and more preferably of 85 to 90% by weight of CaO and of 15 to 10% by weight of Ca(OH)2, in the field of the separation of solid matter from the liquid of a suspension. The invention also involves a novel method for treating a sludge, in which the solid matter is concentrated, dried and recovered using the delayed reactivity partly prehydrated lime. It additionally relates to, as a novel industrial product, the purified sludge obtained according to the method.

Abstract: The invention discloses a process to implement and maintain large water bodies with color, transparency, and cleanness characteristics similar to swimming pools or tropical seas, at low cost. The present invention also discloses a structure to contain large water bodies, comprising a system for the removal of impurities and surface oils by means of skimmers and a suction device to clean said structure.

Abstract: The invention relates to an aqueous polymer dispersion comprising an anionic water-soluble dispersion polymer comprising in polymerized form a monomer mixture comprising (i) one or more anionic monomers, (ii) a first non-ionic vinyl monomer which is acrylamide, and (iii) at least one second non-ionic vinyl monomer; a water-soluble salt and a stabilizer, wherein the water soluble salt is present in an amount of at least 2.0% by weight, based on the total weight of the dispersion. The invention further relates to a process for producing the aqueous polymer dispersion, use of the aqueous polymer dispersion as a flocculating agent in papermaking or for water purification, and a process for producing paper which comprises adding one or more drainage and retention aids comprising the aqueous polymer dispersion to an aqueous suspension containing cellulosic fibres and then dewatering the obtained suspension.