Abstract: The invention concerns a process that uses an ion exchanger resin to recover the sodium contained in industrial alkaline waste and, in particular, in the "red mud" and sodium effluents coming from the manufacture of aluminum hydrate according to the Bayer process. It includes putting the alkaline resins (1), usually "red mud" in the form of an aqueous suspension in contact with an RH.sup.+ type cationic resin, preferably, a carboxylic resin to attach the sodium selectively and quantitatively to the resin (5) and then to extract it quantitatively in the form of NaOH (8) by displacement using a lime suspension (6), preferably, lime milk. The resin (9), after attaching the calcium, is then regenerated for reuse at the beginning of the process (2) by elution of the calcium as CaCl.sub.2 (12) with a diluted hydrochloric acid solution (10).

Abstract: An apparatus and method for separating oxides of heavy isotopes of hydrogen (deuterium oxide, oxides of tritium and mixed isotope oxides) from light water (H2O) which is contaminated with these heavy hydrogen isotopes such as that currently being discharged in cooling water from nuclear power plants. A central aspect of this invention includes a plurality or bundle of elongated hollow core fibers which are positioned within an elongated enclosed housing having a feed water inlet, an exit stream outlet, and a permeate outlet. At least a portion of the hollow core fibers are at least partially filled or packed with small beads which are comprised of a porous exchange resin carrying waters of hydration. Porosity is controlled by the degree of cross-linking and bead diameter of the exchange resin which is preferably combined with aluminum sulfate or ammonium hydride to form (RSO.sub.3).sub.3 Al or RSO.sub.3 NH.sub.4.

Abstract: A fluid stream has material selected from the group consisting of radioactive matter and metals removed from it. An example material to be removed is cesium ions. A silico-titanate composition have a mole ratio of Si:Ti of 0.01:1.7 is provided in the fluid stream. The material to be removed is them permitted to bind to the silico-titanate composition. The silico-titanate composition may include a metal dopant MD present in a mole ratio of MD:Ti up to 1.0. The silico-titanate may also be a cation M present in a mole ratio of M:Ti up to 2.0.

Abstract: A process for removing lead and copper from drinking water discharged from a drinking water outlet while suppressing the concentration of phosphate ions comprising directing the water through a matrix comprising phosphate mineral with a very low phosphate solubility, and a solid carbonate mineral which is slightly soluble in water. The matrix is sized such that there is sufficient contacting between the water and the matrix to form a lead phosphate precipitate, reduce the lead concentration in the water to below 15 parts per billion, and suppress the phosphate ion concentration to 5 mg/L, preferably 3 mg/L, or below.

Abstract: A filter sheet is provided which comprises a self-supporting fibrous matrix having immobilized therein particulate filter aid and particulate ion exchange resin, wherein said particulate filter aid and particulate ion exchange resin are distributed substantially uniformly throughout a cross-section of said matrix. A process for removing ionic impurities from a photoresist solution is also provided which comprises passing the photoresist solution through said filter sheet to remove ionic impurities therefrom.

Abstract: A process for removing toxins from blood is disclosed. The process involves contacting the blood with a microporous ion exchanger to remove toxins in the blood. Alternatively, the blood can be contacted with a dialysis solution which is then contacted with the ion exchanger. The microporous ion exchangers are represented by the following empirical formulae:A.sub.p M.sub.x Zr.sub.1-x Si.sub.n Ge.sub.y O.sub.m (I)andA.sub.p M.sub.x Ti.sub.1-x Si.sub.n Ge.sub.y O.sub.

Abstract: A composite surface at which at least two materials having different isoelectric points are exposed is cleaned by an HF dip, followed immediately by a dip in a low pH surfactant, followed by an optional rinse in deionized water, followed by a dip in ammonium hydroxide, followed immediately by a dip in a high pH surfactant, and followed by a rinse in deionized water. By maintaining the relatively extreme pH levels of the immediately preceding steps, the surfactant dips significantly prevent the formation of a charge differential between the different portions of the composite surface, which charge differential would otherwise tend to cause any particles present to remain on one portion of the composite surface or the other. The surfactant properties of surfactant dips help remove any particles from the composite surface, resulting in substantial removal of particles from the composite surface.

Abstract: A filter cartridge which can be filled with granular filter material, approximately in the shape of a cup open at the top which can be closed with a lid. This filter cartridge has a base (1) with at least one outlet aperture (2), has a sieve means (12) and side walls (3) and is for filtering liquids, in particular water. In order that even small granulate particles of, for example, .ltoreq.200 .mu.m wide cannot pass through the outlet apertures (2) in the base (1), and nevertheless good through flow of the liquid to be purified is ensured, it is provided according to the invention that 1-64 outlet apertures (2) are provided, each with a fabric insert (12) with plastics frames (11), with a pore size in the fabric of 50 .mu.m to 300 .mu.m, preferably 80 to 200 .mu.m.

Abstract: A method of backwashing a filter includes a) supplying a backwash liquid via a conduit toward one end of a filter bed; b) aspirating air into the backwash liquid upstream of the bed; c) introducing a mixture of air and backwash liquid into the filter bed at the one end thereof; and d) expelling backwash water and air from an opposite end of the filter bed. A related filter system includes a filter basin having a bed of filter media material therein; a filtrate channel proximate the basin; at least one tubular underdrain header in the bed and in fluid communication with the filtrate channel; and a backwash pump having a backwash water supply conduit selectively engageable with the underdrain header for supplying backwash liquid to the bed. The backwash water supply conduit includes a nozzle for aspirating air into the supply conduit at a location between the backwash pump and the bed.

Abstract: An underdrain unit of the type having air and water backwash for backflushing a granular filtration system has improved retention structure for retaining folded, perforated stainless steel underdrain plates against the floor of the tank drain. The retention structure is in the form of hollow horizontal tubes which not only hold the folded plates in place but also serve to deliver backwashing air. Thus, instead of air delivery tubes being mounted above a series of brackets that hold the folded plates in place against the floor, the air delivery in the system of the invention is via the same structural element which retains the folded plates. Embodiments are described for gravel bed systems and for sand filter systems.

Abstract: A method for removing selenium from waste water is disclosed comprising reducing selenium oxide with carbohydrazide in a solution comprised of the selenium oxide to form elemental selenium.

Abstract: Water treatment plant having pretreatment means, such as in particular means of desanding, degreasing, physico-chemical pretreatment such as coagulation and flocculation and biological pretreatment, as well as means of separating the solid particles contained in the untreated water, characterized in that the solid/liquid separation means are contained within a construction of circular shape, and the untreated-water supply means as well as at least one of the pretreatment means are incorporated in a structure in the shape of an isosceles trapezoid whose projected apex lies on a diametral axis of the construction of circular shape containing the separation means, whose sides are formed by the two tangents to the circular construction leading from the said projected apex and whose base is tangent to the circular construction at the point of intersection of this construction with the diametral axis.

Abstract: A Stormwater Drain Filter for removing sediment and liquid hydrocarbons comprised of a tank having a central outlet which flows into a sewer inlet and is surrounded by a floating boom which is hydrophobic and liquid hydrocarbon absorbent.

Abstract: In a process for the partial desalination of water, especially of drinking water, with a mixture of weakly acid cation exchangers and strongly basic anion exchangers, whereby the charged ion exchangers are regenerated by CO.sub.2 -containing water, if required, with the addition of CaCO.sub.3, CaCO.sub.3 /MgO, Ca(OH).sub.2 or the like. Simultaneous with the partial desalination, the organic carbon compounds present in the water are reduced, whereby the charged ion exchangers are intermittently regenerated with HCl, NaCl, NaOH, or a mixture of NaCl and NaOH.

Abstract: A method is provided for removing contaminants from water. The method comprises contacting the contaminants in the water with an organoclay having a positive or negative charge on its surface. Using this method, organic and inorganic contaminants can be removed with such charged organoclays.

Abstract: A modular water treatment and purification system, suitable for home use, is connected to a water supply and contains a closed fluid treatment circuit extending to a water outlet. The closed fluid circuit flows through a plurality of replaceable water treatment modules each having a specific water treatment function, such as the removal of a particular material from the water by the use of filtration, carbon adsorption, ion exchange or the addition of a chemical to balance the desired water conditions. Preferably the circuit also includes traversing a radiation device, for example an ultra violet light, for the purpose of sanitizing the water.

Abstract: A septic system and method for the removal of nitrogen contaminants, such as nitrates and ammonia, from a wastewater effluent, which system and method includes employing one or more zeolite tanks, which contains a regenerable, granulated zeolite material to receive wastewater effluent from a septic tank, and to capture the nitrogen contaminants, such as nitrate and ammonia, and retain the nitrogen contaminants in the zeolite material allowing the treated, decontaminated effluent to flow out of the tank into a leach field. The system and method includes for periodically regenerating the zeolite material in the zeolite tank, after the zeolite material has become substantially exhausted, and restoring the zeolite material in the zeolite tank for reuse. The system provides for removal of the displaced nitrogen contaminants generated from the regeneration of the zeolite material in the zeolite tank.

Abstract: The surprising ability of the polysilicate microgels commonly known as "activated silica" to adsorb and to release heavy metals selectively as a function of pH is used in a novel method for separating metals from dilute aqueous solution by means of selective precipitation with and recovery from an activated silica absorbent, selected changes to the pH. The process is particularly intended for the economic purification of contaminated waste streams to recover valuable but toxic heavy metals from such effluents at a lower cost than hitherto possible, using an activated silica substrate which may be regenerated by alkali treatment.

Abstract: A filter with a horizontally fed filter chamber having loose bulk material as the filter medium has a wall on the upstream side and downstream side to hold back the loose bulk material in the filter chamber. The filter chamber includes a compressed air-lift pump disposed inside of the filter chamber for pumping the loose bulk material from a bottom area of the filter chamber, through a bottom lifter connected with a stand pipe to an upper rinse chamber, and a hopper disposed at a bottom of the filter chamber having entrance slots and surrounded by a chamber that is provided with a rinse water inlet tube connected to a raw water chamber.

Abstract: In a developing, etching and stripping apparatus, photoresist developing and stripping chemicals are drawn off into separate circulatory paths in each of which they are pumped through a heat exchanger, a series of tangential filters, an ultraviolet contactor and a collection tank. Permeate from the filters is returned to the developing or stripping stage, and solutions with high concentrations of solids are removed from the collection tanks for disposal. A similar system is used to recycle metal stripping solutions such as nitric acid-containing solutions, allowing recovery of metals.