Abstract: Disclosed is an economical process for the purification of water containing soluble and sparingly soluble inorganic compounds using single-stage or two-stage membrane processes that integrate membrane water purification with chemical precipitation softening and residual hardness and silica removal from the membrane concentrates using ion exchange resins and silica sequestering media, respectively.

Abstract: Disclosed is an economical process for the purification of water containing soluble and sparingly soluble inorganic compounds using single-stage or two-stage membrane processes that integrate membrane water purification with chemical precipitation softening and residual hardness and silica removal from the membrane concentrates using ion exchange resins and silica sequestering media, respectively. The purified water recovery is not adversely affected by design and/or operational deficiencies in the chemical precipitation softening system that may result in higher residual hardness and silica in the supernatant from the clarifier.

Abstract: Disclosed is an improved method for extending the useful life of a reverse osmosis membrane having a high pressure side and a low pressure side, the membrane used for separating soluble and sparingly soluble inorganic materials from an aqueous solution, the process comprising introducing an aqueous solution containing the soluble and sparingly soluble inorganic materials to the high pressure side of a reverse osmosis membrane and pressurizing the aqueous solution on said high pressure side to produce liquid on the low pressure side substantially free of said inorganic materials. Solution containing concentrated inorganic materials is transformed from the high pressure side of the reverse osmosis membrane to a high pressure side of a microfiltration membrane, and soluble inorganic materials transferred to the high pressure side of the microfiltration membrane was precipitated to provide solution containing particles of the inorganic materials.

Abstract: Provided is a method of removing carboxylic acids from effluent streams comprising the steps of pretreatment which may include chemical conditioning, clarification and filtering the effluent stream to remove suspended solid particles to provide a filtered stream. The filtered stream is subjected to membrane filtration to remove organic compounds having a molecular weight of greater than 150 while simultaneously permitting permeation of the membrane by the carboxylic acids to provide a membrane filtered stream. A reverse osmosis membrane is provided having a high pressure side and a low pressure side, and the membrane filtered stream is introduced to the high pressure side of the reverse osmosis membrane. The carboxylic acids are concentrated in the high pressure side of the reverse osmosis membrane.

Abstract: This invention discloses a cost-effective process for separating contaminants and a wide-range of fouling material from surface water, ground water and from industrial effluents. Having undergone effective pre-treatment, the water can be purified further by using high-surface area spirally wound micro-filtration (MF), ultra-filtration (UF), nano-filtration (NF) or reverse osmosis (RO) membranes. High-quality potable water free from pathogen and other contaminants is thus produced at low-cost from the pre-treated surface water and ground-water. Conversely, pre-treated industrial effluents are further purified at a relatively low-cost using NF or RO membranes, thus producing water suitable for recycle or surface discharge. The process of this invention uses cationic inorganic and/or polymeric flocculants to coagulate and flocculate the water-borne colloidal matter (e.g. clays, iron hydroxides, naturally occurring matter (NOM's), etc.

Abstract: Disclosed is an economical single stage membrane process intended to provide very high overall water recoveries from natural sources or wastewater containing high concentrations of hardness and other inorganic scale-forming compounds while preventing scale formation on the membrane and prolonging the useful life of the membrane. The water is first pre-treated in order to separate all suspended matter using a suitable oil separation device, dissolved air flotation, coagulation, flocculation, clarification, single or multi-media filtration, ultra-filtration, micro-filtration or a suitable combination of these pre-treatment steps. The pre-treated water is then purified using a simple, economical single stage membrane system operating at a suitable pressure depending on the water TDS and desired permeate recovery. In order to prevent scale formation on the membranes, the membrane concentrate is softened using a “low-cost” ion exchange softening resin with high selectivity for hardness precursors.