Other

Zenon Environmental Inc.

Chemetics International Company, Ltd.

Zenon Airport Environmental, Inc.

Riad A Al-Samadi

Andrew Benedek

Cheung K Li Kwok Cheong

Disclosed is a process that uses reverse osmosis (RO) or nanofiltration (NF) membranes and ion exchange (IX) water softening resins to maximize the production of drinking water, purified industrial service water or recycled purified municipal or industrial effluents. The membrane and ion exchange units are configured in a manner that enables operation of the system at high permeate recoveries in the range 90% to 99%, thus producing purified drinking water with a minimum volume of wastewater to drains and a very low membrane cleaning or membrane replacement frequency. The process mitigates membrane fouling and scale formation and minimizes the use of water treatment chemicals including acidic and alkali solutions and sodium chloride salt that is normally required to regenerate the IX resin.

High recovery drinking water process

Disclosed is a versatile multi-use high water recovery process that integrates the use of water purification membranes including reverse osmosis and nanofiltration with ion exchange water softening resins in a number of configurations that optimize operation and achieve maximum membrane permeate recoveries while eliminating the use of fresh water, sodium chloride and other chemicals needed to regenerate the IX resin. The invention provides process mobility and flexibility that enable selection of optimum process configurations and features to address variability in the Influent Water quality.

Multi-use high water recovery process

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.

Enhanced high water recovery membrane process

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.

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 &ldquo;low-cost&rdquo; ion exchange softening resin with high selectivity for hardness precursors. The softened, suspended solids free, high TDS concentrate is recycled at a sufficient rate and blended with the high-hardness Influent Water in order to provide further, purification, thus achieving the desired high permeate recoveries while preventing scale formation. A small volume of membrane concentrate is bled out of the system in order to control the osmotic pressure.

High water recovery single stage membrane process

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.), followed by filtration using a multi-media filter, charge neutralization and reversal and final filtration using a 5-micron cartridge filter. These pre-treatment steps provides a good quality water having a low Silt Density Index and a significant negative zeta potential, thereby ensuring against irreversible chemical fouling of the spirally-wound membranes.

Water treatment process for membranes

Disclosed is a two-stage high pressure high recovery process utilizing two reverse osmosis membrane systems intended to provide very high overall water recoveries from contaminated inorganic scale-containing water in an economical manner while preventing scale formation on the membrane and prolonging the useful life of the membrane. The first stage of the process involves using a low pressure membrane system to preconcentrate scale compounds while purifying the bulk volume of the scale-containing water (using antiscalants with pH control) and combining the influent water with a recycle stream of concentrate from the second stage membrane process in order to prevent scale formation. This first stage membrane system is followed by a second stage membrane system wherein the concentrate from the first stage membrane system is treated further at higher pressure in order to provide purification of the remaining preconcentrated stream and achieve very high overall water recoveries. Scale formation in the first stage and second stage membrane systems is prevented by the recycle of 'softened' water containing a very low concentration of scale-forming compounds and containing a high concentration of soluble salts to both stages in a specific proportion that represents an economically viable process, while ensuring adequate permeate quality. The second stage membrane concentrate stream is 'softened' whereby hardness compounds such as calcium, magnesium, carbonate, sulphate, silica and other sparingly soluble compounds are removed by suitable device before it is recycled to the two membrane purifying stages.

High water recovery membrane purification process

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. In a preferred embodiment, purified liquid (permeate) is neutralized and passed to the high pressure side of a second pass reverse osmosis membrane, producing a high-purity final permeate for plant reuse or discharge to surface water.

Recovery of carboxylic acids from chemical plant effluents

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.

Microfiltration enhanced reverse osmosis for water treatment

A process for the recovery of sulphuric acid from a waste acid stream containing ammonium sulphate comprising vaporizing the waste acid and subsequently converting the ammonia and sulphur dioxide generated to nitrogen and sulphur trioxide, respectively. The process provides an economic method for the regeneration of the waste sulphuric acid from a methyl methacrylate production process.

Growing community of inventors

Burlington, Canada

Riad A Al-Samadi