Abstract: The present invention is directed to a process for treating an oily substrate, including a mixture comprising water and oily material or a mixture comprising water, solids and oily material as components, and wherein such treatment comprises contacting the oily substrate with a solvent for the oily material, and wherein the solvent for the oily material ranges in solubility in water from sparingly soluble to substantially water insoluble, in the presence of an added comminuting and dispersing surfactant, to produce by such contacting at least one phase differentiating interface, and to thereby render one or more of the components of the oily substrate separable.

Abstract: Process for softening hard water by precipitation of calcium carbonate. The hard water is rendered alkaline, e.g. by the addition of sodium hydroxide, and is then contacted with a large excess of calcium carbonate crystals whose size does not exceed 100 microns, whereby precipitation occurs within a short contact time of the order of 2-60 seconds. Upon separation of soft water from calcium carbonate the bulk of the latter is recirculated and excessive amounts are removed.

Abstract: An apparatus and method for resolving an emulsion that has an aqueous phase and an organic phase that includes components capable of polymerizing or coagulating. The emulsion is added to a tank and heated (with gentle agitation to avoid formation of hot spots) to a temperature sufficient to prevent it from setting up inside the tank. A non-corrosive inorganic separation aid incapable of initiating polymerization of the emulsion or its constituents is added to the tank with mixing to cause the emulsion to separate into its constituent aqueous and organic phases. The contents of the tank are then allowed to settle and the separated aqueous and organic phases are removed from the tank.

Abstract: There is disclosed a pulsating sludge bed clarifier especially for the treatment of low turbidity waters, which uses incline plates in the sludge bed and some recirculated sludge. The clarification is greatly enhanced by recirculating a relatively small part of the sludge concentrate to a reactor chamber used for the premixing of water to be treated and the coagulant. The small amount of recirculated sludge cuts down significantly on the polymer flocculant, which is the most expensive chemical in the process that is required to be used, and can also serve to improve the adsorption of colors and similar materials, increase the density of the sludge blanket, and improve the rate of throughput of the system.

Abstract: A highly stable dispersion e.g. an oil-in water emulsion having a pH of from about 4 to about 12 is destabilized by treatment with a composition comprising a precipitant e.g. aluminum sulphate, a clay and a marl.

Abstract: An effluent precipitation and neutralization chamber for mixing and neutralizing spent photographic developer and fixer. A baffle and long folded ribbons inside the chamber promote mixing of the developer and fixer. A source of iron ions such as fine steel wool is immersed in the fluids. Ion exchange between the steel wool and the photographic fixer recovers silver from the fixer. The desilvered fluid is diluted with wash water before it is discharged from the chamber.

Abstract: A process for separately removing zinc and iron from acidic wastewater. The process involves adding alkali metal hydroxide to the acidic wastewater (below about pH 4) to achieve a first pH of about 4.8 to at most about 5.4 and precipitate an iron hydroxide-containing precipitate at this pH. The precipitate from the wastewater is separated and then additional alkali metal hydroxide is added to achieve a second pH in the range from about 8.8 to about 9.4. A zinc hydroxide containing precipitate forms at this second pH and is then recovered by filtration.

Abstract: New systems for the purification of liquids containing suspended solids and/or dissolved solid materials basically include a conical flocculator unit and a conjoined conical clarifier unit. The flocculator has a cylindrical lower portion, frustum middle portion and large diameter cylindrical top portion while the clarifier is essentially a large diameter cylindrical top portion over a lower frustum portion. Water or other liquid to be purified enters the flocculator lower portion via opposed, unequally sized nozzles to assume a helical flow upward past a series of deflector plates positioned at the top of the lower flocculator portion while a sludge blanket forms therein. A double flume plus slot arrangement located at the junction of the flocculator with the clarifier separates solids from liquid as fluid flow from the flocculator passes into the clarifier where it is subjected to further separation of sludge from clarified liquid with part of the sludge being recycled to the flocculator.

Abstract: The invention concerns a process for lowering or eliminating the sodium and potassium ion content in various forms of waste. According to the process, waste is treated with the residue, itself regarded as a pollutant since rich in fluosilicic acid, discharged from the manufacture of sulfuric acid on a calcic ore based on calcium phosphate.

Abstract: Method for treating drilling effluents containing ligno-sulfonates wherein, successively, sulfuric acid is injected in order to cause coagulation, a cationic polyelectrolyte is injected to cause a flocculation and solids are separated from the liquid by centrifugation or dewatering compaction.

Abstract: A method of coalescing a disperse phase within a continuous phase of a fluid mixture comprising the steps of:(a) supplying said fluid mixture to a primary inlet of a coalescing device;(b) passing said fluid mixture from said primary inlet to a substantially cylindrical chamber of said coalescing device, said primary inlet being arranged substantially radially of said chamber;(c) introducing a fluid to said chamber via a secondary inlet of said coalescing device, said secondary inlet being arranged substantially tangentially to said chamber, thereby setting said fluid mixture into rotating motion within said chamber; and(d) allowing said fluid and said fluid mixture to exit said chamber via an outlet of said coalescing device having a longitudinal axis arranged coaxially with said chamber, such that said exiting fluid and fluid mixture are caused to spin about said longitudinal axis to cause coalescing of said disperse phase.

Abstract: A dewatering porocess and apparatus for recovering water from waste drilling fluid for concurrent reutilization in an active drilling operation includes a storage area, an intermixer for introducing treatment chemicals into the waste drilling fluid and a centrifuge. Flocculation is chemically induced in the waste drilling fluid as it passes through the intermixing means for introducing treatment chemicals into the waste drilling fluid. The waste drilling fluid is then transferred to the centrifuge wherein it is separated into solid waste and clear reuseable water. The water is returned to the storagge area and may be chemically adjusted prior to being returned to the drilling rig.

Abstract: Liquid separator and method of separating oil and water components of a liquid mixture wherein the oil component is made up of droplets of a less dense phase in a more dense water phase, using a hydrocyclone for separating the components. A less dense component of the mixture separated by the hydrocyclone is passed from the underflow of the hydrocyclone to a filter device for further separation. A residence vessel may be provided upstream of the hydrocyclone for coalescing the mixture prior to passage into the hydrocyclone.

Abstract: A method and apparatus for treating a liquid mixture to separate a clarified fraction therefrom leaving a concentrated sludge fraction involve injecting a flocculent material into the liquid mixture; and inletting the liquid material and the flocculent maerial tangentially into a vertical tank having a perforated plate spaced from its upper end dividing the tank into an upper chamber and a lower chamber, a to produce a flow in the lower chamber having a rotational velocity in the horizontal direction adjacent the outer periphery of the lower chamber, and a lower rotational velocity in the horizontal direction adjacent the center of the lower chamber. The holes in the perforated plate define reduced-area passages from the lower chamber to the upper chamber producing a vertical flow of low velocity in the lower chamber and of higher velocity through the passage in the perforated plate.

Abstract: A method of washing an upflow filter between service runs employs a filter bed having a non-buoyant particulate filter layer through which influent to be filtered is directed in an upward direction, and through which liquid employed in the washing operation is directed in an upflow direction. A two-stage washing operation includes the steps of first directing a combination of air and liquid in an upflow direction through the filter layer with the velocity of the liquid being less than the minimum fluidization velocity of the filter layer, for disrupting only some floc retained in the filter layer during a previous service run, and thereafter directing only liquid in an upflow direction through the filter layer at a velocity less than the minimum fluidization velocity of the filter layer for removing disrupted floc from the filter layer while leaving some floc attached to said particulate media of the filter layer.

Abstract: Method and apparatus for removing impurities from a laundry wash effluent including the steps and means therefor of acidifying the solution, infusing a gas into the solution and coalescing the released contaminant droplets by means of baffle plates into droplets sufficient to achieve buoyany with respect to the solution. The resulting top layer of buoyant droplets is skimmed from the solution and the remaining solution is adjusted to a neutral pH for discharge.

Abstract: An improved method and apparatus for removing sludge from a spray booth tank using a single pump for withdrawing liquid including sludge from the tank. A portion of the liquid from the pump is returned to the tank through eductors for agitating liquid in the tank. At least a portion of the liquid from the pump flows through a hydrocyclone separator. Sludge from the separator is collected in a settling tank. A small portion of the clarified liquid from the separator flows through an aspirator pump to the booth tank and the remainder of the clarified liquid is returned directly to the booth tank. The aspirator pump returns excess liquid from the settling tank to the booth tank.

Abstract: This invention relates to the removal of hypochlorite groups from aqueous effluent solutions, so as to permit the disposal of the effluent by deep well injection. More particularly this invention relates to the catalytic decomposition of such hypochlorite groups from scrubbing water effluent used to remove chlorine from a gaseous effluent, wherein a solid catalyst is dissolved, recycled and reprecipitated in situ.

Abstract: A method of removing silicon from a waste hydrochloric acid pickling solution is disclosed which comprises stirring the waste solution long enough to form a sludge having a particle size such that the sludge can be separated by a conventional means such as filtration through a filter of at least 0.1 .mu.m in pore diameter, centrifugation or sedimentation. The stirring period can be greatly reduced by adding to the waste pickling solution sludge recovered from an aged waste hydrochloric acid pickling solution or a carbonaceous material such as carbon black having hydrophilic groups on the surface. The sludge is also useful as a filter medium in filtration of the waste pickling solution to remove silicon. The present method can decrease the silicon content to 0.01% or less in terms of converted SiO.sub.2 /Fe.sub.2 O.sub.3 weight ratio.

Abstract: The method of filtering and metering a liquid sample set forth herein includes the steps of providing a first recipient (1) in which the sample is placed, the volume of the sample being greater than the quantity to be metered, providing a second recipient (2) into which the sample is decanted in the same proportions, interposing filtering means (7) between the first and second recipients, decanting into the first recipient a quantity of the sample less than the excess quantity contained in the second recipient and providing a third recipient (3) into which is decanted from the second recipient the desired quantity of liquid samples. The method may be employed for example in processing the adenosine triphosphate (ATP) molecule.

Abstract: A method is provided for removing heavy metal ions from an aqueous solution to yield a less contaminated aqueous effluent. The method comprises coprecipitating the heavy metal ions with a carrier precipitate which is formed in situ within the aqueous solution.

Abstract: Apparatus and methods for continuous sedimentation-type separation of solids from liquids of a feed slurry in a thickener-clarifier-type tank operated by overflow removal of clarified liquid and underflow removal of a concentrated underflow slurry by using a flocculant in a zone of intense mechanical agitation provided by a rotatable impeller rotated at tip speeds of between approximately 300 to 600 feet per minute to produce relatively small, bead-like floccules directly above the concentrated underflow slurry.

Abstract: A chemical mixture for treating spent dryfilm stripper and developer solutions by mixing the spent solutions with a solution of aluminum sulfate and borax in controlled amounts causing a surface absorption reaction which results in a slurry of a non-sticky, benign precipitate in a supernatant liquid. The supernatant liquid contains the dissolved heavy metals. The non-sticky precipitate does not interfere with the ph measurement which indicates when the reaction is complete, and the benign precipitate can be filtered out for disposal.

Abstract: The invention provides a method of transporting a liquid A past or around a barrier, by adding a solute S to liquid A on one side of the barrier and correspondingly removing solute S from liquid A on the other side of the barrier, the solute S being such as to change the density of the liquid A when dissolving in it, thereby providing a motive force for its motion around the barrier. An example of the application of the invention is in a two-part electrolytic cell (1) comprising electrowinning and electrofining half cells (2 and 3, respectively), wherein the metal, solute S, is electrowon into a liquid (16,16a), liquid A, on one side of the cell's common electrode (4), the barrier, in the electrowinning half cell (2), and electrolytically removed from the liquid (17,17a) on the other side of the common electrode (4), in the electrorefining half cell (3).

Abstract: The present invention relates to a high rate method for combining waste materials to produce valuable products for agricultural, horticultural, sylvicultural or public use. Specifically, the present invention combines the steps of alkaline stabilization, beneficiating and pelletizing waste materials, such as wastewater treatment plant sludge or animal excrement and reaction with carbon dioxide, to thereby convert the waste materials to useful products such as soil conditioners or fertilizer supplements.

Abstract: Methods and apparatus for controlling the movement of materials having different physical properties when one of the materials is a fluid. The invention does not rely on flocculation, sedimentation, centrifugation, the buoyancy of the materials, or any other gravity dependent characteristic, in order to achieve its desired results. The methods of the present invention provide that a first acoustic wave is propagated through a vessel containing the materials. A second acoustic wave, at a frequency different than the first acoustic wave, is also propagated through the vessel so that the two acoustic waves are superimposed upon each other. The superimposition of the two waves creates a beat frequency wave. The beat frequency wave comprises pressure gradients dividing regions of maximum and minimum pressure. The pressure gradients and the regions of maximum and minimum pressure move through space and time at a group velocity.

Abstract: The present invention concerns a floatation clarifying/flocculating procedure for purifying liquid, in which particles of impurities present in a liquid to be purified or impurities dissolved in the liquid which have been converted into particle form with the aid of flocculating chemicals, are separated from the liquid to be purified and carried to the surface of the liquid, to form thereon a sludge bed. The sludge bed is conducted out through a sludge trough to a sewer or equivalent, and flocculating chemicals are then added to the remaining liquid thus already at least partially purified, so that the chemicals form dirt particles with the impurities still present in a dissolved state but which have not yet been removed from the remaining liquid.

Abstract: When flocculating an aqueous suspension of suspended solids using a high molecular weight synthetic polymeric flocculant the shear stability of the flocs is increased if the polymeric material includes polymeric particles of below 10 .mu.m dry size. The flocculated solids can therefore be subjected to shear without increasing the amount of discrete suspended solids in the aqueous medium and generally they are suspended to shear by shearing the aqueous medium containing them, either before dewatering, generally on a centrifuge, piston press or belt press, or by continuously agitating them, for instance in a chemical reaction medium. The polymeric material is generally formed by mixing into water polymeric particles made by reverse phase or emulsion polymerization in the presence of added cross linking agent. Alternatively particles insolubilized by insoluble monomer may be used. A reverse phase dispersion of water soluble polymer may be used if the particles remain undissolved, e.g.

Abstract: The present invention provides a process and apparatus for separating oil water and solids from emulsions. More particularly, the present invention provides a process and apparatus for continuously separating oil, water and solids from stable mixtures thereof, comprising heating the mixture to at least about 115.degree. C., rapidly cooling the mixture to below 100.degree. C., separating the solids from the liquids and separating the water from the oil. Preferably, the invention also includes the step of adding a flocculant prior to cooling the mixture.

Abstract: Method of treating liquid by sedimentation in which reagents are injected into a flow of untreated liquid and there is created in the flow a colloid mixing and stabilization area; the flow is passed into an intermediate aggregation area and then into a sedimentation area equipped with separator plates from which clarified liquid is taken; characterized in that insoluble granular material which is more dense than the liquid is injected into the liquid in predetermined proportions in the mixing area where the flow is made turbulent, turbulence is induced in the intermediate aggregation area to maintain the granular material in suspension, virtually all of the granular material is brought into the sedimentation area, the sludge recovered in the sedimentation area is removed, the granular material is removed therefrom (D) and is recycled after cleaning.

Abstract: The present invention solves the problem of managing resin-containing waste liquors within the cellulose pulp industry. The invention relates to a method for purifying resin-containing waste liquor in the manufacture of cellulose pulp, in which method a pH-adjusting chemical is, when necessary, added to resin-containing waste liquor removed from the cellulose pulps, so that the pH of the waste liquor will lie within the pH range 1-7, and in which a water-soluble organic polymer is added to the waste liquor in the form of a forwardly moving liquid stream. The method is characterized by dividing up the requisite amount of polymer into part quantities which are introduced into the liquid stream on at least two occasions, by subjecting the liquid stream to a pronounced shearing and/or turbulent treatment process, and by subsequently separating agglomerated resin from the waste liquor.

Abstract: An externally cooled cylindrical vessel has a draft tube centered in the lower half thereof. A continuous circulation seeded with tartars crystals includes a fast downward flow through the draft tube and a slow upward flow outside the draft tube. The circulation induces crystal growth and the removal of tartars from the liquid. A coning zone is defined in the vessel above the draft tube. The slow upward flow moves toward the calming zone, facilitating classification of the crystalline matter which is reintroduced into the fact downward flow. The liquid product from which the tartars has been removed and which is collected in the upper section of the vessel is tapped off by an overflow port located near the top of the vessel.

Abstract: Bitumen froth is treated in a circuit comprising a plurality of serially connected mixer and inclined plate settler units. A light hydrocarbon diluent moves countercurrently through the circuit. Thus, as the bitumen content of the stream being settled diminishes, the concentration of diluent in that stream increases.

Abstract: A method of treating spent dryfilm stripper and developer solutions by mixing the spent solutions with a solution of aluminum sulfate and borax in controlled amounts causing a reaction which results in a slurry of a non-sticky, benign precipitate in a supernatant liquid. The supernatant liquid contains the dissolved heavy metals. The non-sticky precipitate does not interfere with the ph measurement which indicates when the reaction is complete, and the benign precipitate can be fillered out for disposal.

Abstract: A process for dewatering sewage sludges of which the sludge solids contain less than 70% of organic matter, and whose dewatering characteristics have been improved by adding organic flocculants, on a filter press, wherein the sewage sludges are concentrated by adding an organic flocculant during thickening by gravity sedimentation from 0.5-5.0% by weight of sludge solids to 6-14, and especially 8-12, % by weight of sludge solids, the sewage sludges are mixed with additives, such as finely divided coal or ash or mixtures thereof, in an amount of from 0.5 to 1.5 parts by weight per part by weight of sludge solids, and the sludges are treated, before, during or after admixture of the additives, with a further 2-8 kg or organic flocculant/tonne of sludge solids and are then dewatered on the filter press.

Abstract: A method of and apparatus for the thickening of mud-like slurries produced during the course of industrial processes, e.g. the thickening of red muds produced during operation of the Bayer process for the production of alumina. The invention involves the step of feeding the slurry, a fluocculating agent and washing liquor to a deep thickening vessel having an underflow outlet for the thickened slurry and an overflow outlet for clarified washing liquor. The solids content of the slurry leaving the underflow outlet is increased and kept constant by the use of a stirrer having a number of generally vertical rod-like members rotated in the vessel above the underflow outlet. The stirrer enhances dewatering of the slurry and prevents undue build up of thick inactive mud which may block the outlet or cause fluctuations in the solids content of the thickened slurry.

Abstract: A method for removing waste oil particles having a particle size generally in the range of 1-97 microns from a waste water stream includes first transmitting seed oil particles having a particle size of at least 20 microns into the waste water stream. The seed oil is allowed to mix with waste oil particles suspended in the waste water stream. Oil is then removed which includes a combination of the seed oil and combined waste oil particles.

Abstract: A process for the removal of solid deposits, especially calcium-, iron-, manganese-containing incrustations and mixtures thereof, from water supply installations wherein an aqueous solution comprising a mineral acid, preferably hydrochloric acid corresponding to a normality of the solution of 0.001 N to 6 N, and hydrogen peroxide in a proportion of 0.05 to 20% by weight of the total solution, is applied to the interior surfaces of the installations by, for example, spraying or rinsing.

Abstract: A paint spray booth detackifying composition which includes mixtures of; melamine-formaldehyde polymers and polyvinyl alcohol polymers; and mixtures of melamine-formaldahyde polymer, polyvinyl alcohol polymer and styrene-acrylate polymer.

Abstract: A method for dewatering a slurry of solid particles suspended in a liquid using a twin belt press dewatering system, comprising the following steps:feeding the slurry of solid particles into the dewatering system;feeding a cationic amine salt solution into the dewatering system at a point just prior to the mixing drum, the cationic amine salt being a latex copolymer of acrylamide and dimethylaminoethylmethacrylate sulfuric acid salt having a mole ratio in the range between about 30:70 to 70:30, preferably 53:47;mixing the cationic amine salt solution with the slurry of solid particles in the mixing drum; andfeeding the cationic amine salt solution/slurry mixture to the twin belt press, whereby the slurry of solid particles is dewatered. The cationic amine salt solution having a strength of less than 1% and a polymer concentration of about 35%.

Abstract: A process for treating hot, pressurized geothermal brine in a liquid-vapor phase separator comprises contacting the brine in the separator with between about 0.2 and about 1.5 parts per million of a defoaming agent so as to substantially reduce the amount of foaming in the separator caused, in part, by steam bubbling through the brine. The preferred defoaming agents are polyglycols having molecular weights between about 1000 and about 2500, those agents having molecular weights below about 1000 being too volatile and those above about 2500 being too difficult to solubilize in the brine.

Abstract: Methods and apparatus for controlling the movement of materials having different physical properties when one of the materials is a fluid. The invention does not rely on flocculation, sedimentation, centrifugation, the buoyancy of the materials, or any other gravity dependent characteristic, in order to achieve its desired results. The methods of the present invention provide that a first acoustic wave is progpagated through a vessel containing the materials. A second acoustic wave, at a frequency different than the first acoustic wave, is also propagated through the vessel so that the two acoustic waves are superimposed upon each other. The superimposition of the two waves creates a beat frequency wave. The beat frequency wave comprises pressure gradients dividing regions of maximum and minimum pressure. The pressure gradients and the regions of maximum and minimum pressure move through space and time at a group velocity.

Abstract: A cross linked high molecular weight polymer formed from a water soluble monomer or blend of monomers and which has IV and/or solubility and/or rheology properties indicating that it would be unsuitable for use as a flocculant can be used as a flocculant after shearing the polymeric material. The shearing may be applied to the polymeric material before addition to the suspension that is to be flocculated or can be applied to the suspensionthat is being flocculated. The shearing increases the intrinsic viscosity of the polymeric material and can improve its rheology and solubility. The polymeric material must be of high molecular weight.

Abstract: A method and apparatus for treating acidic water, such as mine acid water is provided. The apparatus is readily portable and comprises a reaction vessel having an aerator motor operatively associated therewith. Water to be treated is received within said reaction vessel and is treated by having a neutralizing agent and oxidant by way of the aerator motor introduced simultaneously into the system. Because of instantaneous elevation of pH resulting from the simultaneous introduction of oxidant and the neutralizing agent, the reaction time is greatly reduced and the equipment required is small, compact and easily transported.

Abstract: A system for extracting moisture from sludge of the type handled by municipalities and industries. The system involves the use of a feed line where the sludge is mixed with a chemical treating agent adapted to achieve flocculation. The sludge is conveyed, with or without some partial separation of moisture, to a progressive cavity continuous press for feeding of the sludge through the press. The press is of the type employing a slotted or screened housing with an interior shaft so that the cavity of the press is defined between the shaft and the housing. The size of this cavity progressively decreases from the inlet end to the outlet end of the press whereby the mixture is gradually compressed as it moves through the press. Moisture contained in the mixture is thereby extracted through the housing which is designed to at least minimize passage of solids. A discharge chamber is located at the outlet end of the press for collecting the partially dehydrated mixture.

Abstract: A waste-treatment process for water-based printing operations which employ inks comprising aqueous dispersions of polyester or polyesteramide materials containing water solubilizing sulfo-salt groups, comprising providing in an agitated vessel a substantially homogenous system of water and multi-valent cation, adding the waste aqueous dispersion of polyester or polyesteramide material from the printing operation to the vessel, allowing ion interchange and insolubilization of the material in the water to occur, and physically separating the water from the insolubilized material.

Abstract: A process for separating finely divided solid particles from a hydroprocessing liquid product which comprises treating a heavy hydrocarbon feed having an asphaltene content of at least 1 wt. % so as to obtain an unstable product characterized by heavy molecular weight molecules which promote the agglomeration of said finely divided solid particles and thereafter feeding said unstable product to a precipitating zone provided with a centrifugal decanter for precipitating the agglomerated solid particles and said heavy molecular weight molecules in said precipitating zone wherein at least 80 wt. % of the finely divided solid particles is recovered.

Abstract: Wastewaters which contain carbon black and ash and originate from high temperature processes and in which the carbon black is present in a very finely divided state and partially in a colloidal state are treated and disposed of by a process in which the wastewater is treated with calcium carbonate or calcium hydroxide and an organic flocculant and subjected to a two-stage filtration and the resulting filter cake containing carbon black and ash is subjected to an aftertreatment with an aqueous iron salt solution.

Abstract: A novel sewage purification method is provided herein. The method includes adding particular amounts of at least alum, a cationic polyelectrolyte and an anionic surface active compound to the sewage or other impure water in any order, then turbulently mixing the added chemicals within the sewage or other impure water, then allowing particulate matter to settle as sludge, and finally drawing off pure water. Preferably, part of the sludge is recycled to the sewage or other impure water to be treated.

Abstract: When flocculating an aqueous suspension of suspended solids using a high molecular weight synthetic polymeric flocculant, the shear stability of the flocs is increased if the polymeric material includes polymeric particles of below 10 .mu.m dry size. The flocculated solids can therefore be subjected to shear without increasing the amount of discrete suspended solids in the aqueous medium and generally they are subjected to shear by shearing the aqueous medium containing them, either before dewatering, generally on a centrifuge, piston press or belt press, or by continuously agitating them, for instance in a chemical reaction medium. The polymeric material is generally formed by mixing into water polymeric particles made by reverse phase or emulsion polymerization in the presence of added cross linking agent. Alternatively, particles insolubilized by insoluble monomer may be used. A reverse phase dispersion of water soluble polymer may be used if the particles remain undissolved, e.g.