Abstract: An ion exchange process for removing arsenic from drinking water is disclosed which uses a mixed ion regenerant and generates minimal levels of waste.

Abstract: The disclosed invention is a fixed bed ion exchange system from removing arsenic from water. It employs a combination of electronically controlled process steps and specific systems configurations to duplicate the effects of moving resin beds from one operating position to another as is required in moving bed ion exchange water purification systems. The invention combines features of single fixed bed ion exchange systems with those of a moving bed system.

Abstract: The disclosed invention is a fixed bed ion exchange system from removing arsenic from water. It employs a combination of electronically controlled process steps and specific systems configurations to duplicate the effects of moving resin beds from one operating position to another as is required in moving bed ion exchange water purification systems. The invention combines features of single fixed bed ion exchange systems with those of a moving bed system.

Abstract: The disclosed invention is a fixed bed ion exchange water purification system. It employs a combination of electronically controlled process steps and specific systems configurations to duplicate the effects of moving resin beds from one operating position to another as is required in moving bed ion exchange water purification systems. The invention combines features of single fixed bed ion exchange systems with those of a moving bed system. The invention applies to the treatment of water having typical industrial and drinking water concentrations of various ions.

Abstract: A system and method for determining the concentration of nitrate ions in a nitrate ion-containing water sample which also contains chloride ions and bicarbonate ions is disclosed. The potentially interfacing chloride ions are suppressed by reaction with a cation exchange resin in the silver form. The potentially interferring bicarbonate ions are suppressed by reaction with a cation exchange resin in the hydrogen form. The sample, after having been treated with the two resins is passed into a conductivity cell with the conductivity being directly related to the nitrate ion concentration of the sample. The device and method find advantageous application in automated systems for monitoring and controlling water treatment facilities.

Abstract: The invention relates to a method for separating nitrate from waters containing a significant amount of sulfate ion. Nitrate removal is accomplished by passing the water to be treated through a bed of a strong-base anion exchange resin which is a tributyl amine derivative of a copolymer exemplified by styrene-divinyl benzene. The tributyl species has been found to have an unusually high selectivity for nitrate over sulfate and provides not only a high capacity for nitrate removal but also economies in regeneration due to the ability to operate with only a partially regenerated resin bed.

Abstract: A process for removing nitrate ions from a contaminated aqueous feed solution containing the same, and also chloride ion, by forcing the solution through a reverse osmosis membrane which permits passage of nitrate ions through the membrane and into the product water while rejecting chloride ion and other anions such as sulfate and bicarbonate, and concentrating such anions in the brine waste water. An anion exchange resin bed charged in the chloride form is placed in the product water during the reverse osmosis operation. Reverse osmosis product water containing nitrate is treated by the anion exchange resin bed to remove the nitrate ions and replace them with chloride ions. The resulting product water is essentially free of the nitrate impurity and a concentrated waste brine stream is obtained containing essentially chloride salts.

Abstract: A water purification unit particularly adapted for household use, and for operation at high pressures, including two main co-operating parts forming a chamber, with a seal positioned between such parts, and a cap compressing the seal and holding the two parts together. The interior of the chamber can contain one or more filtering elements such as a particulate matter filter, a carbon filter or a reverse osmosis filter. To withstand high internal pressures without leakage or damage, mechanical connections are provided within the chamber to form a further positive connection between the two main parts forming the chamber, so as to maintain such filter elements in position within the chamber.