Abstract: A method of recovering elementary phosphorus from an aqueous sludge containing about 1 to about 15 wt % dispersed particles of phosphorus is disclosed. To the sludge is added about 1 to about 20 wt %, based on the weight of the phosphorus present in said sludge, of a phosphate salt that has the general formula: where R is an alkali metal or ammonium and n is 0 to 30. The phosphorus in the sludge is melted and the solids in the sludge are separated from liquid phosphorus and water. Liquid phosphorus is then separated from the water.

Abstract: A wastewater treatment system for use with a conventional septic tank, or other small-scale wastewater treatment facility, for enhancing wastewater treatment without requiring complex control or maintenance limitations. The system incorporates a plurality of primary functions that combine to oxidize, nitrify, denitrify and remove water borne total dissolved solids prior to effluent discharge. Included is a fluidized-bed reactor containing biofilm attached to carrier particulates for use in the purification of wastewater. The fluidized-bed reactor is configured to include two distinct regions, namely a “lower” aerobic region and an “upper” anoxic region, during normal operating conditions. The lower aerobic region uses aerobic facultative bacteria to oxidize Carbonaceous Biochemical Oxygen Demand (CBOD), organic (Kjeldahl) nitrogen, and ammonia while consuming the dissolved oxygen in the water.

Abstract: A method of phosphorous reduction in stormwater runoff using iron humate, such as in the form of a filter, a layered filter bed, a stacked wall or a liner. The stormwater (fluid) runoff is sent to a fluid retention area such as a retention pond, wetland reservoir or the like where the runoff is filtered through iron humate. While the runoff is filtered, the iron humate absorbs or chemically retains the phosphorous in the runoff to produce filtered runoff with a reduced level of phosphorous. In an alternate embodiment, the runoff can be pumped from a retention pond into a iron humate filter where the runoff is filtered. In another alternate embodiment, the iron humate filter may be placed in a trench below ground to intercept and filter groundwater flows.

Abstract: A process for treating BOD, nitrogen and phosphorus containing wastewater. The process includes introducing wastewater influent into an anaerobic zone having activated sludge and mixing the wastewater influent with the activated sludge in the anaerobic zone to form a mixed liquor. The mixed liquor is introduced into an oxygen-deficit aeration zone, and denitrified mixed liquor from the oxygen-deficit aeration zone is recycled to the anaerobic zone for mixing therein with wastewater. The process also includes transferring the mixed liquor from the oxygen-deficit aeration zone to an oxygen-surplus aeration zone, transferring a portion of the mixed liquor from the oxygen-surplus aeration zone to a settling zone wherein a supernatant is separated from settled sludge and recycling at least a portion of the settled sludge to the oxygen-deficit aeration zone as recycled activated sludge.

Abstract: The apparatus of the present invention generally comprises a wastewater contact tank that is broken into three distinct zones: a selector zone positioned between a stabilization zone and a contact zone. The entire influent is introduced into the selector zone which is maintained in an anoxic condition. Baffles positioned within the selector zone permit control of microorganisms levels present in the zone. The wastewater introduced into the selector zone and treated via the microorganisms present therein, flows over a weir into the contact zone. In the contact zone, the solids suspended in the liquor (the mixture of the wastewater and activated sludge) settle to the bottom and pass through a line which returns it to the selector zone. The return line, however, includes a valve which controls the rate of passage. The treated wastewater (which includes waste activated sludge and treated water) passes from the contact zone into the clarifiers for final processing.

Abstract: This invention provides a method for reducing phosphorous in a body of water. This method comprises calcining a plurality of rocks and collecting carbon dioxide formed as a result of the calcining process; crushing the plurality of calcined rocks; pumping source water from the body of water into to a plurality of retaining cells; flocculating the phosphorus in the source water by introducing the plurality of calcined rocks into the source water in the retaining cells; settling out a phosphorous precipitate formed by the flocculating act; adjusting the pH level of the flocculated source water to a predetermined range of values by pumping carbon dioxide created by the calcining of the rocks into the source water to created treated water; and transferring the treated water back to the body of water.

Abstract: A method is providing for treating waters, such as standing and flowing waters and waste waters, soils, sediments and/or silts. At least one alkaline earth metal peroxide is brought into contact with such waters or the like, especially to effect immobilization of phosphates and heavy metals except manganese and iron therein.

Abstract: A method for the conditioning of phosphoric acid containing solutions is described, wherein the solution is converted to a solid material by adding an aluminum compound. This solid material can readily be stored in disposal sites because it is not water-soluble. This method is particularly suited for the conditioning of phosphoric acid containing solutions from metal processing. An apparatus (10) for carrying out the method comprises a mixing tube (12) with a longitudinal axis (M) as well as an inlet (14) and an outlet (16). At least two liquid supply nozzles (18 and 20) opens into the mixing tube inlet (14) and, with respect to the inlet cross-sectional area of same, into a central area. Moreover, at least one gas supply nozzle (22) which is arranged radially outward of the liquid supply nozzles (18 and 22) opens into the mixing tube inlet (14). The longitudinal axis (G) of each gas supply nozzle (22) is inclined relative to the longitudinal centre axis (M) in such manner that said axes do not intersect.

Abstract: A process which comprises using a tank or compartment suitable for both anoxic and anaerobic conditions for biologically removing both nitrogen and phosphorus from waste water.

Abstract: A process and system for enhanced phosphorus removal in a wetlands wastewater treatment facility is disclosed. A portion of the effluent is recycled back through a media which is capable of removing phosphorus from water through sorptive processes.

Abstract: An apparatus to transfer gas to or from a liquid has a flexible and oxygen permeable but liquid water impermeable membrane, a flexible and gas permeable spacer, an inlet conduit, an outlet conduit and a non-rigid restraint system. When used for treating wastewater, an aerobic biofilm is cultured adjacent the planar elements, an anoxic biofilm is cultivated adjacent the aerobic biofilm and the wastewater is maintained in an anaerobic state. A first reactor for treating wastewater has an anaerobic section, a plurality of gas transfer membrane modules, and an aerobic section. A biofilm is cultivated on the surface of the gas transfer membranes in fluid communication with the anaerobic section. Biological reduction of COD, BOD, nitrogen and phosphorous are achieved. In a second reactor, phosphorous is also removed chemically in a precipitation branch.

Abstract: A wastewater treatment process that provides improved reduction of total solids through endogenous respiration while reducing biochemical oxygen demand and utilizing biological nutrient reduction. The wastewater treatment process uses an efficient aeration delivery system to drastically reduce the time needed to oxidize organic matter, and re-circulates, shreds and homogenizes the organic matter and microorganisms and oxygenates the entire mass many more times than traditional systems resulting in a greater biological solids digestion rate.

Abstract: A partially soluble lanthanide compound and methods for use in removing phosphate from water. Preferably the compound is used in removing phosphate from water in swimming pools, spas, and similar structures. Alternatively, a combination of compounds having varying solubilities may be used to remove phosphate from water. Several water treatment techniques are disclosed, as well as a variety of different methods for delivery of the active ingredients. These delivery methods include use of a slurry of the active reagent in solution as well as a tablet, powder, or granulated structure. Additionally, the water treatment techniques may incorporate the use of a combination including both enzymatic compositions and compounds for phosphate removal.

Abstract: Methods and compositions for removing phosphate from swimming pool waters are disclosed. The compositions include both soluble and substantially insoluble lanthanide carboxylates, preferred examples being lanthanum glycolate and lactate. The methods include the addition of the lanthanide compounds to the bulk of the pool water, but preferably involve the loading of the pool filter with the composition and the circulation of pool water through the filter to effect the removal of dissolved phosphate in the water.

Abstract: In a liquid treating process according to the present invention, colloidal particles in stable hydrated states or in meta-stable hydrophobic colloidal states in a liquid are rendered hydrophobic and separated from liquid molecules by an electric field formed by a microwave. The separated colloidal particles are allowed to collide against one another to become flocculated under a cavitation effect by a ultrasonic wave having a frequency in a low frequency range, and the liquid is deodorized by an electromagnetic ultrasonic wave having a frequency in a high frequency range. Therefore, it is possible to easily and reliably remove the colloidal particles dissolved in the liquid and to deodorize the liquid without need for a large-scaled equipment.

Abstract: An electrolytic process and apparatus purifies contaminated bulk aqueous solutions and remediates soil. The apparatus is an electrolytic treatment or remediation unit consisting of one or more electrolytic cells having a cathode chamber separated from at least one anode chamber by a separation membrane. The cathode chamber has cathode plates positioned at an angle to the perpendicular or vertical axis of the cell made of valve metals with an irreducible oxide coating. Non-turbulent flow of the solution in an interfacial zone adjacent to the cathode is controlled by the evolution of hydrogen during electrolysis, resulting in a steady state flow of colloidal particles and cations in the cathode-solution interface sufficient to collapse the Gouy-Chapman layer, thereby causing total and irreversible agglomeration of all colloidal particles. A separation membrane separates cathode and anode chambers and allows conductivity driven ionic transfers, and prevents electro-osmotic reflux of the anolyte.

Abstract: Disclosed is a method of recovering elemental phosphorus from a sludge that contains water, dirt, and elemental phosphorus. In the first step, the sludge is melted. A mixture is formed of the melted sludge and about 0.5 to about 5 wt % of an oxidizing agent, based on the weight of elemental phosphorus in the sludge, and about 75 to about 580 wt % water, based on the weight of the sludge. The mixture is stirred until a continuous elemental phosphorus phase forms. The purified phosphorus phase is separated from the mixture.

Abstract: The present invention relates to a high speed coagulant-flocculant and sedimentation method for treating waste water, which permits a speedy treatment of waste water including stormwater runoff and also permits a valuable reuse of the sludge produced in the course of treatment.

Abstract: A method of treating sewage or waste water for removing nitrogen and phosphorus as well as organic materials in the sewage or waste water, and an apparatus therefor are provided. The method applies intermittent aeration and dynamic flow to an equipment having at least a pair of reaction basins with intermittent aeration means, a clarifier with sludge transfer means, and a filter for passing liquid without passing solid between the reaction basins. According to the method, the efficiency of removing nutrient salts is excellent and stable even in the treatment of waste water having low content of influent organisms and low C/N ratio.

Abstract: The invention is a process for treating waste slurry generated in the electric furnace production of phosphorus in which a superatmospheric reactor is operated at an elevated temperature to destroy cyanides, phosphorus, and phosphides present in the waste. The process transforms wastes from the phosphorus electric furnace process into non-hazardous solid, liquid, and gaseous wastes that meet environmental regulatory requirements regarding solids for phosphorous, cyanide, phosphine and cyanide flux, and TCLP metals, and regarding the filtrate for UTS metals.

Abstract: A method of processing waste water comprises atomizing waste water under selected atmospheric conditions to achieve substantially complete phase change of the water. The atomization is conducted by spraying waste water from a nozzle mounted on a tower adjacent a catchment area for collecting ice crystals produced by the phase change of the atomized waste water into ice crystals, under atmospheric conditions favorable to freezing of atomized water droplets into ice.

Abstract: This invention relates to a method for treating various kinds of drain water and waste liquid which treatment now becomes a problem, for example, drain water and waste liquid containing hardly removable phosphorus and nitrogen, waste liquid containing organochlorine compounds such as tetrachloroethylene, etc., excretive drain water from a piggery containing organonitrogen compounds at a high level, waste liquid containing heavy metals such as lead, hexavalent chromium, cadmium and the like, drain water from dairy product plants, fishery processing plants, slaughterhouses, etc. which contains water soluble protein at a high level, drain water from pulp plants, photo developing waste liquid, car wash drain water containing a mixture of car polishing wax and detergent and the like by the use of porous ceramics provided with amorphous pore surfaces.

Abstract: This invention relates to a method for treating various kinds of drain water and waste liquid which treatment now becomes a problem, for example, drain water and waste liquid containing hardly removable phosphorus and nitrogen, waste liquid containing organochlorine compounds such as tetrachloroethylene, etc., excretive drain water from a piggery containing organonitrogen compounds at a high level, waste liquid containing heavy metals such as lead, hexavalent chromium, cadmium and the like, drain water from dairy product plants, fishery processing plants, slaughterhouses, etc. which contains water soluble protein at a high level, drain water from pulp plants, photo developing waste liquid, car wash drain water containing a mixture of car polishing wax and detergent and the like by the use of porous ceramics provided with amorphous pore surfaces.

Abstract: Embodiments of the present invention relate to methods and systems for removal of contaminants from aqueous solutions. The methods and systems of these embodiments are particularly suited to removal of arsenic species as well as transition-metals, post-transition-metals, phosphates and other contaminants in aqueous solutions. The methods and systems of embodiments of the present invention provide for the addition of a reagent to a contaminated solution in combination with a pressurization process and a depressurization process. Contaminant particulates and solids produced in these processes may be removed by conventional separation techniques.

Abstract: A single step wet oxidation process for treating wastewaters containing organic species, with or without heteroatoms, and anions of strong acids, e.g. sulfate or phosphate ion, or cations of strong bases, e.g., sodium, potassium or calcium ions, and which may contain ammonium ion and/or nitrate ion in addition to added ammonium ion and/or nitrate ion was developed which on thermal treatment near the critical temperature of water removes substantially all the COD and nitrogen through conversion to water, carbon dioxide or carbonate species, nitrogen gas and small amounts of nitrous oxide. Key to the success of the process is the balancing of all reducing species with an equivalent amount of oxidizing species and the balancing of all strong acid anions with strong base cations and including at least 0.06 acetate ion for moles of nitrate in the wet oxidation process.

Abstract: A method for biological nutrient control to modify nutrient levels in open waters so that these waters can produce food, be used for recreation, and be healthy areas for human activities or for other uses. This system can be designed and operated to increase, decrease or maintain nutrient levels. Large numbers of filter feeding shellfish which produce pseudofeces (with one notable process exception) can be retained in slow to intermediate water flow where phytoplankton production can be counted on to support them. These Molluscan shellfish are held in aquaculture production and used to filter particulate and colloidal materials as well as microscopic plants from the water. The shellfish then process this material. The removal of particulate and colloidal material by the shellfish from the water column can be used to increase light penetration, thereby allowing photosynthesis to occur at an increased depth, providing oxygen to the sediment/water interface.

Abstract: A material and method for removal of environmental oxyanions (and especially phosphates), the material comprising a substrate such as a clay modified with complexing elements selected from Group IIIB, Group IVB, and lanthanide elements (or a mixture of such elements). The resultant modified substrate can bind oxyanions and make them unavailable for utilisation in the environment; in the case of phosphates, by algae and the like. The method includes forming a capping of material at the sediment/water interface, applying the material in the form of pellets at the sediment/water interface, or injecting the pellets into the sediment.

Abstract: A partially soluble lanthanide compound and methods for use in removing phosphate from water. Preferably the compound is used in removing phosphate from water in swimming pools, spas, and similar structures. Alternatively, a combination of compounds having varying solubilities may be used to remove phosphate from water. Several water treatment techniques are disclosed, as well as a variety of different methods for delivery of the active ingredients. These delivery methods include use of a slurry of the active reagent in solution as well as a tablet, powder, or granulated structure. Additionally, the water treatment techniques may incorporate the use of a combination including both enzymatic compositions and compounds for phosphate removal.

Abstract: A single step wet oxidation process for treating wastewaters containing organic species, with or without heteroatoms, and anions of strong acids, e.g. sulfate or phosphate ion, or cations of strong bases, e.g., sodium, potassium or calcium ions, and which may contain ammonium ion and/or nitrate ion in addition to added ammonium ion and/or nitrate ion was developed which on thermal treatment near the critical temperature of water removes substantially all the COD and nitrogen through conversion to water, carbon dioxide or carbonate species, nitrogen gas and small amounts of nitrous oxide. Key to the success of the process is the balancing of all reducing species with an equivalent amount of oxidizing species and the balancing of all strong acid anions with strong base cations. The former ensures good removal of organic species, ammonium ion and nitrate ion. The latter ensures maintaining the pH in the range of from 1.

Abstract: An apparatus for treating a secondary treated wastewater effluent. The apparatus comprises an anoxic first zone for accepting the secondary effluent wherein the first zone includes heterotrophic bacteria, a carbon source, and an outlet structure including a limestone aggregate. The apparatus further comprises a second zone including an entrance structure that is in fluid communication with the outlet structure and an exit structure in fluid communication with the second zone. The exit structure includes a cationic exchange medium wherein the exit structure discharges the effluent to a disposal mechanism such as a subsurface disposal field.

Abstract: A process for the treatment of waste waters containing chemically reducible dissolved organic and inorganic pollutants and suspended mater in particulate or colloidal form. The process comprises of contacting the water with metallic iron or ferrous ions (Fe2+), or mixtures thereof, in the presence of promoter metals, such as Cu, Pd, Pt, Au, Ag, and Ni, or oxides, sulfides and other insoluble compounds of these meals, which catalyze the redox reductions carried out by the iron or ferrous reagents. The production of ferric ions (Fe3+) as a final iron oxidation product allows for the simultaneous coagulation and precipitation of suspended colloidal and particulate solids out of the aqueous phase. In addition to the main reductive reaction scheme, the system performs a multitude of secondary reactions involving the ferrous and ferric ions produced in-situ which allows for the simultaneous removal of specific target pollutants, such as phosphate and hydrogen sulfide.

Abstract: A process for treating sulphate-containing waste water comprises introducing a feedstock comprising sulphate-containing waste water, into a pond. The sulphate-containing waste water is subjected to biological sulphate reduction in the pond, thereby to convert dissolved sulphate anions to dissolved sulphide anions. Treated waste water, containing the dissolved sulphide anions, is withdrawn from the pond.

Abstract: One or more flow equalization basins or lagoons are utilized for performing hydrolysis of ATP as the first stage of biological phosphorus reduction, selective reduction of biological oxygen demand (BOD), deamination, and denitrification of nitrate and nitrite compounds, in addition to simultaneous flow equalization of wastewater produced by food processing operations on a 2-to-6-day schedule. The inflow half of a single basin or an entire first basin is. operated on an anaerobic/anoxic basis. The outflow half of the single basin or an entire second basin, if present, is operated on an anoxic/aerobic basis. A downstream nitrification reactor is operated on an aerobic/anoxic basis or is operated exclusively on an aerobic basis if followed by an anoxic reactor.

Abstract: A method for neutralizing organophosphorus agricultural chemicals with a composition having a quaternary ammonium complex component, an oxidizer component and a solvent. After an organophosphorus agricultural chemical is passed through a pathway, an agricultural chemical neutralizer is used to neutralize residual agricultural chemical within the pathway.

Abstract: A method of treating animal manure solids comprises contacting the solids with a treatment composition comprising AlCl3.nH2O or Al(NO3)3.mH2O, or the residue of AlCl3.nH2O or Al(NO3)3.mH2O, to form a treated waste product, wherein n is from 0 to 10, and m is from 0 to 12. The treatment amount can be effective to reduce phosphorus solubility in the manure; reduce phosphorus runoff and/or phosphorus leaching from fields fertilized with manure; inhibit ammonia volatilization from the manure; flocculate solids in the manure; reduce pathogens in the manure; increase the nitrogen content in the manure; and/or reduce acid rain and PM-10s associated with the manure.

Abstract: Disclosed is a method of recovering elemental phosphorus from a sludge that contains water, dirt, and elemental phosphorus. In the first step, the sludge is melted. A mixture is formed of the melted sludge and about 0.5 to about 3 wt % of an oxidizing agent, based on the weight of said elemental phosphorus in the sludge, and about 75 to about 400 wt % water, based on the weight of the sludge. The mixture is stirred until a continuous elemental phosphorus phase forms. The purified phosphorus phase is separated from the mixture.

Abstract: The invention relates to a method of controlling a biological wastewater purification plant, in which the wastewater is aerated in an activation tank in the presence of an activated sludge and, to influence the properties of the activated sludge, phosphorus is added under controlled concentration, which comprises measuring the phosphorus concentration in the activated sludge for the control of the phosphorus addition and controlling the phosphorus addition in such a manner that the phosphorus concentration in the activated sludge is greater than or equal to a lower limit and is less than or equal to an upper limit. By means of the method according to the invention, the effluent values of a biological wastewater purification plant can be optimized and the limit values in the effluent of a wastewater purification plant prescribed by the authorities can be complied with better than hitherto.

Abstract: A process for treating thickened phosphatic clay suspensions, waste clay and phosphogypsum produced in the processing of phosphate ore by water beneficiation and chemical processing, the thickened phosphatic clay suspension having a solid content of from about 4 to about 40 percent by weight, includes mixing a sufficient amount of deflocculating agent with a thickened phosphatic clay suspension to cause deflocculation of the suspension to an extent sufficient to reduce the viscosity thereof to a value enabling the deflocculated suspension to be readily pumped from one location to another, the deflocculating agent comprising an alkali compound of a phosphorus oxide. The deflocculated suspension of reduced viscosity is pumped from one location to another and separated into a clay suspension and a phosphatic mineral and sand suspension.

Abstract: A method for treating sludge from wastewater purification is described. In the method, a sludge is treated, which contains phosphorus and at least one metal which originates from precipitation chemicals and which is selected among divalent iron and aluminum, the pH of the sludge being adjusted to below 4, preferably below 2, for dissolving the content of the phosphorus and said metal in the sludge; the remaining sludge is separated; the solution relieved of sludge and containing phosphorus and said metal is treated for precipitation of the phosphorus content of the solution as FePO4 at a pH of 2-3; and precipitated FePO4 is separated. The method is characterized in that the solution which remains after separation of FePO4 and which contains said metal from the precipitation chemicals, is recycled to the wastewater purification. The phosphorus content of the solution is precipitated as FePO4 by adding an at least equivalent amount of Fe3−.

Abstract: A new method of forming mask ROM in the manufacture of an integrated circuit device has been achieved. A semiconductor substrate is provided with field oxide areas defined and a gate oxide layer overlying the semiconductor substrate. A gate electrode layer is deposited overlying the gate oxide layer. The gate electrode layer and the gate oxide layer are patterned to form gate electrodes. Ions are implanted to form source and drain junctions. A buffer layer is deposited overlying the gate electrodes, the source and drain junctions, and the field oxide areas. The buffer layer is etched down to expose the gate electrodes while leaving a protective thickness of the buffer layer overlying the source and drain junctions. Ions are implanted through the gate electrodes into the semiconductor substrate to selectively code the mask ROM devices and to complete the mask ROM devices in the manufacture of the semiconductor device. A coding mask controls the ion implantation to selectively code the mask ROM.

Abstract: A method for the removal of metal cyanides or oxoanions from aqueous streams such as waste water streams with compounds containing 1,4-diazabicyclo[2.2.2]octane. Preferred compounds are polymers formed by free radical polymerization of N-4-vinyl benzyl-N1-1,4-diazabicyclo[2.2.2]octane dichloride (VBBD) such as copolymers poly (VBBD/acrylamide) and poly (VBBD/dimethyl amino ethyl acrylate benzyl chloride quaternary salt. Poly(1,4-dimethylbenzyl-1,4-diazabicyclo[2.2.2]octane dichloride) for the same purposes is also disclosed.

Abstract: Disclosed herein is a high efficiency apparatus for treating nitrogen and phosphorous in sewage. The apparatus includes a sludge denitrification tank supplying sludge to an anaerobic tank.

Abstract: Polynucleate metal hydroxide anionic compounds and method for their production. The compounds have the formula: MaNb(OH)cXdYeZf.(H2O)g wherein M is a tri- or more valent metal ion; N is a divalent metal ion that forms a soluble salt with anions X, Y or Z; OH represents the level of basicity; X is a monovalent anion; Y is a divalent anion; Z is a trivalent anion; a is 1; b is from 0.15 to 2.0; c is from 0.3 to 5; d is from 0 to 3; e is from 0.1 to 2.25; f is from 0 to 1; and g is greater than 4 where the compound is in the form of an aqueous solution, or from 0 to 20 where the compound is not in the form of an aqueous solution. The compounds are useful for water treatment for removal of suspended solids and for various applications in the paper industry.

Abstract: A method of treating an effluent such as acid mine drainage wherein the pH of the effluent is increased by dissolving metallic ions e.g. of zinc into the effluent, and the metallic ions are allowed to react with contaminants, such as sulphates or phosphates in the effluent, to form a metal-contaminant complex which is then precipitated from the effluent.

Abstract: Methods and compositions are disclosed for treating swimming pool waters in order to remove one or more nutrients necessary for algal growth and to accelerate the breakdown of objectionable chloramines within chlorinated pool waters. The target nutrients of preference are those containing phosphorus or nitrogen. Phosphorus nutrients are preferably removed by ion-exchange with finely divided lanthanum carbonate, or by direct precipitation in the pool with liquid lanthanum chloride. Nitrogen nutrients (including, in particular, chloramines) may be removed (possibly with the aid of catalysts and in separate reactors). The same reagents used to scavenge phosphates are useful in this regard, the nitrogen being released from the pool water as a nitrogenous gas. To allow the fine lanthanum carbonates to be conveniently handled in the pool environment, they may be linked to larger carrier particles, such as those of diatomaceous earth, or they may be embedded within porous beads formed from polymers or gels.

Abstract: The present invention relates to a process for the biological purification of wastewater in which a liquid stream is fed to the aerobic biological purification stage, which liquid stream has already been freed in advance from undissolved substances using a membrane separation process.

Abstract: Phosphates and chromates are selectively removed from contaminated water by a new class of sorbent, referred to as a Polymeric Ligand Exchanger (PLE). The exchanger bed comprising a styrene-divinylbenzene or polymethacrylate matrix having an electrically neutral chelating functional group with nitrogen or oxygen donor atoms, and a Lewis-acid type metal cation, such as copper, bonded to the chelating functional group in a manner that the positive charges of the metal cation are not neutralized. PLEs are very selective toward phosphates and chromates, chemically stable, and also amenable to efficient regeneration.

Abstract: A method is disclosed for reducing the concentration of metal soaps of partially esterified phosphates from a hydrocarbon flowback fluid resulting from a hydraulic fracturing fluid operation using an alkaline aqueous-based additive solution.

Abstract: A method for treating phosphate-containing waste water comprising treating phosphate-containing waste water with a metal hydroxide complex as a phosphate adsorbent represented by formula (1):M.sub.1-x.sup.2+ M.sub.x.sup.3+ (OH.sup.-).sub.2+x-y (A.sup.n-).sub.y/n(1)wherein M.sup.2+ represents at least one divalent metal ion selected from the group consisting of Mg.sup.2+, Ni.sup.2+, Zn.sup.2+, Fe.sup.2+, Ca.sup.2+ and Cu.sup.2+, M.sup.3+ represents at least one trivalent metal ion selected from the group consisting of Al.sup.3+ and Fe.sup.3+, A.sup.n- represents n-valent anion, 0.1.ltoreq.x.ltoreq.0.5, 0.1.ltoreq.y.ltoreq.0.5 and n is 1 or 2 to adsorb phosphate is provided.

Abstract: A wastewater treatment process having improved solids separation characteristics and reduced biochemical oxygen demand (BOD) in the purified wastewater comprising the steps of: passing wastewater through a main aerobic biological oxidation zone and therein oxidizing a portion of the BOD a portion of the ammonia nitrogen content (NH.sub.