Abstract: A wastewater treatment system and method for chemical precipitation and removal of metals from wastewater in a continuous or batch treatment process includes an ion-selective sulfide electrode and a reference electrode disposed in a precipitation tank for measuring an electrochemical potential therebetween in a predetermined range. A controller unit is provided which is responsive to the electrochemical potential in the predetermined range and is connected to a precipitant feed unit for automatically controlling the chemical precipitant fed into the precipitation tank.

Abstract: A method is provided for removing metals from a fluid stream containing these metals. The method involves treating the fluid stream with a water soluble ethylene dichloride ammonia polymer having a molecular weight of from 500 to 100,000 that contains at least 5 mole percent of dithiocarbamate salt groups to form a complex with the metals. Then, the fluid stream is passed through a filtering device to remove the complexes from the fluid stream.

Abstract: A hydrophobic polyelectrolyte copolymer which is useful in the removal of color in paper mill waste water. The copolymer preferably comprises diallyldimethylammonium chloride and a hydrophobic monomer selected from the group consisting of quaternized dimethylaminoethylacrylates and quaternized dimethylaminoethylmethacrylates.

Abstract: A wastewater treatment system and method for chemical precipitation and removal of metals from wastewater in a continuous or batch treatment process includes an ion-selective sulfide electrode and a reference electrode disposed in a precipitation tank for measuring an electrochemical potential therebetween in a predetermined range. A controller unit is provided which is responsive to the electrochemical potential in the predetermined range and is connected to a precipitant feed unit for automatically controlling the chemical precipitant fed into the precipitation tank.

Abstract: A hydrophobic polyelectrolyte copolymer which is useful in the removal of color in paper mill waste water. The copolymer preferably comprises diallyldimethylammonium chloride and a hydrophobic monomer selected from the group consisting of quaternized dimethylaminoethylacrylates and quaternized dimethylaminoethylmethacrylates.

Abstract: The invention provides a method for decolorizing an effluent stream from a pulp mill plant comprising the step of adding an effective amount of a decolorizing composition including a ferrous sulfate and a water-soluble cationic amine polymer.

Abstract: A process for de-oiling mill sludge employs the steps of admixing mill sludge with water and surface active agent to form a mill sludge slurry which is subjected to high shear agitation to form an oily water emulsion. Then at least 40 weight percent of the solids present in the mill sludge treated is separated from the oily water emulsion.

Abstract: A process for de-oiling mill scale which comprises(a) collecting mill scale and analyzing for oil content; and then(b) slurrying the portion of mill scale containing more than 0.5 weight percent oil in water to achieve an aqueous mill scale slurry having at least 25 weight percent solids content; and then(c) high shear agitating the aqueous mill scale slurry to form a reduced oil mill scale suspension in an oily water emulsion; and then(d) phase separating the reduced oil mill scale from the oily water emulsion forming a reduced oil mill scale and an oily water emulsion; and then(e) fresh water rinsing the reduced oil mill scale to form an oil-free mill scale and a waste wash water; and then(f) recycling the waste wash water to form at least a portion of the aqueous mill scale slurry of step b; and then(g) repeating steps (a) through (f) until the oil-free mill scale contains less than 0.

Abstract: An improved process for the production of alkaline earth, aluminum-containing spinel compositions, preferably magnesium, aluminum-containing spinel compositions and preferably further comprising at least one additional metal component, comprises combining an acidic aqueous solution and a basic aqueous solution containing an aluminum component to form a combined mass; combining the combined mass with an aqueous solution containing at least one alkaline earth metal to form a precipitate; and calcining the precipitate to form a spinel composition. The product spinel composition, preferably with included additional metal components, is particularly suited for use to reduce the amount of sulfur oxides emitted from a catalyst regeneration zone, e.g., a catalytic cracking unit regeneration zone.

Abstract: An improved process for the production of alkaline earth, aluminum-containing spinel compositions, preferably magnesium, aluminum-containing spinel compositions and preferably further comprising at least one additional metal component, comprises adding a basic aqueous solution containing at least one aluminum component to an aqueous solution containing at least one alkaline earth metal component to form a precipitate at defined pH conditions and calcining the precipitate to form a spinel composition. The product spinel composition, preferably with included additional metal components, is particularly suited for use to reduce the amount of sulfur oxides emitted from a catalyst regeneration zone, e.g., a catalytic cracking unit regeneration zone.