Tag:concentrate

№1|2014

WASTEWATER TREATMENT

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UDC 628.316:66.081.63

Pervov A. G., Matveyev N. A.

The use of membranes for surface runoff and recycling car wash water treatment

Summary

The results of investigating the technology of surface runoff and recycling car wash water treatment with the use of reverse osmosis systems equipped with specially designed membrane units with «open» channel that provide for processing water with high concentration of suspended matter are presented. For processing raw wastewater in the membrane unit two concentrating stages are used: at the first stage – reverse osmosis membranes that ensure high quality treatment, and at the second stage – nanofiltration membranes that ensure concentrating solutions with high salt content with the minimum power consumption. The specific feature of the technology is in the utilization of the reverse osmosis concentrate that is removed from the system together with wet sludge. The results of the laboratory studies of storm water membrane treatment with the use of special roll elements with «open» channel and new BLF membranes are presented. It is stated that increasing permeate output to 0.9 results in 2.5–3-fold decrease of the equipment capacity. Car wash water undergoes the same treatment. The pilot tests show that increasing salt concentration in recycling water higher than 17 000 mg/l is impractical. The relationships of the increase of pollutant concentration in permeate and membrane capacity depending on the increase of the salt content in water under treatment and the ratio of volume concentrating in a reverse osmosis unit are presented. The parameters of membrane units operating with wastewater of this type with efficient removal of oil products, detergents and other pollutants are determined. Possible utilization of concentrate is shown.

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№11|2018

WATER TREATMENT

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UDC 628.16.087

FESENKO L. N., Skryabin A. Yu., Bessarabov S. Iu., Pchel'nikov I. V., Ignatenko S. I.

Utilization of concentrate from reverse osmosis units  in the production of electrolytic sodium hypochlorite

Summary

Owing to high efficiency and minimum chemical consumption reverse osmosis and nanofiltration have been widely used in process flow schemes of drinking water demineralization and softening and water preparation for industrial use (in steam boiler-houses, recycling cooling circuits, heat network make up etc.). However, the methods of membrane separation are accompanied by concentrate generation which is very difficult to process and utilize. The data on utilization of concentrates of membrane separation units with obtaining chloride-sodium raw material for the production of electrolytic low-concentrated sodium hypochlorite is presented. Since the waste stream of reverse osmosis units contains elevated concentrations not only of chloride ions but also of Са2+, Mg2+, НCO3- and SO42- ions it would be reasonable at the first stage to reduce the amount of process concentrate by repeated concentrating as per flowchart «nanofiltration-reverse osmosis». Further on the concentrate of nanofiltration containing mainly Са2+, Mg2+ and SO42- divalent ions is subject to chemical treatment as per flowchart: at the first stage with barium compounds; at the second stage with sodium carbonate and hydroxide. This will allow separating practically insoluble BaSO4 from the solution with its precipitation in a vortex reactor or first-stage lamellar separator; then CaCO3 and Mg(OH)2 low-soluble in alkaline environment are precipitated in the second stage reactor. BaSO4, CaCO3 and Mg(OH)2  insoluble salts removed from the mass balance are dewatered in a filter-press and sold as commodity or raw products. Aqueous solution of sodium chloride is repeatedly concentrated by three-stage reverse osmosis to obtain 2–2.5% aqueous solution of table salt – high-grade raw material for the production of electrolytic sodium hypochlorite with 6–8 g/l chlorine equivalent concentration. Chlorine-containing product can be used for drinking and waste water disinfection, biocidal processing of cooling to­wers, heat exchanging units for preventing and removing biofouling, washing ultra-and microfiltration membranes, disinfecting water treatment facilities and equipment, pipelines and other components used in the production of drinking and process water.

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№1|2020

DRINKING WATER SUPPLY

DOI 10.35776/MNP.2020.01.01

UDC 628.16:62-278

Pervov A. G., Golovesov V. A., Spitsov D. V., Rudakova G. Ya.

Ways of reducing the operating costs of membrane units
for the preparation of drinking water from underground water sources

Summary

Experimental investigations have been conducted to determine the main process parameters of membrane units (filtrate yield, the rate of scaling on membrane surface). Basing on the results of the experimental studies the total costs of purification of underground water of various chemical composition were obtained. The studies were conducted on laboratory benches with the use of nanofiltration membranes with various selectivity rates. The consumption of service chemicals and operational costs for the equipment were calculated by the software designed earlier by the authors for determining the process parameters of membrane units. While designing membrane units, nanofiltration membranes with low values of selectivity, power consumption and expenditures for chemicals are preferred. The dependencies of the calcium carbonate scaling rates on membrane types and the multiplicity of volumetric concentration of source water were obtained. A comparison of costs shows that the use of membranes even for cases of water deferrization is more economical than the known traditional technologies.

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№6|2010

ENVIRONMENTAL PROTECTION

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UDC 628.16:62-278

Pervov A. G., Andrianov A. P., Gorbunova T. P.


Development of Membrane Techniques with Reduced Water Consumption for Own Needs

Summary

Issues of the improvement of membrane techniques used in water treatment for the reduction of consumption of a concentrate at reverse osmosis plants and wash water at ultrafiltration units are considered. A change in the design of the membrane canal makes it possible to eliminate the causes of formation of sediment’s crystals. New techniques of water treatment with utilization of the concentrate and reduction of water consumption for own needs are proposed.

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№11|2011

МГСУ - 90 лет

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UDC 628.35:62-278

Pervov A. G.

Solving the problem of waste discharge of stand-alone industrial facilities

Summary

Advanced technologies of wastewater non-biological treatment with reverse osmosis are presented. Formation of concentrate in the process of reverse osmosis is a most difficult problem. The suggested technology provides for the reduction of concentrate flow to less than 1% of the total waste flow subjected to treatment (corresponding to the activated sludge flow removed to sludge beds at biological treatment facilities). Since the concentrate flow depends on the salt concentration in wastewater to be treated it is recommended to supply water with low salt concentration to the water supply system of the facilities. The comprehensive approach to the problem of reducing the discharge of industrial wastes in the environment specifies the use of membrane units for water conditioning (in boiler-houses), drinking water treatment, wastewater treatment and reuse as process water (in irrigation, in heating systems).

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№5|2014

WATER TREATMENT

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UDC 628.165:66.081.63

Removing calcium carbonate from reverse osmosis concentrate
by crystallization with seeding agent

Summary

The technology of removing calcium carbonate from reverse osmosis concentrate in the process of crystallization with seeding agent is described. Seed crystals are suspended in recycling concentrate flow. Owing to calcium carbonate depositing on the seeding agent the total salt content of concentrate decreases and high filtrate flow rate is provided that facilitates concentrate disposal. To implement the technology membrane apparatus with «open channel» are used that are resistant to the impact of membrane transfer of slightly water-soluble salts and suspended matter. Seed crystal growing is provided by dosing into concentrated caustic soda solution. Grown seed crystals were partially removed by sedimentation after hydraulic membrane wash. With the help of experimental diagrams it is possible to determine calcium carbonate crystallization rate depending on the influent water composition, the number of the seeded crystals, and filtrate yield. Process flow diagram of a continuously operating reverse osmosis plant is suggested. The methods of the process design are described: selecting the amount of recycling seed crystals, determining caustic soda consumption and tank size for calcium carbonate sludge precipitation. The estimations showed that to provide for calcium carbonate crystallization du­ring continuous operation of the reverse osmosis plant caustic soda solution in amount of less than 5% of its stoichiometric amount required for the precipitation of the same amount of calcium carbonate from the influent water shall be regularly dosed into the recycling concentrate flow.

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№6|2017

WATER TREATMENT

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UDC 628.165

Pervov A. G., Andrianov A. P., Efremov R. V., Spitsov D. V.

Utilization of reverse osmosis concentrate with removing from it calcium and magnesium ions

Summary

The possible use of pre-developed technology of removing calcium carbonate with seeding agent to reduce the consumption of concentrate from large-scale units operating at the heat power facilities was studied. Concentrate of the operating reverse osmosis units contains inhibitors that inhibit the rate of seed crystal growth and impede the process of its utilization. The correlations between the calcium carbonate growth rate in the concentrate containing inhibiting substances and the dosage of the introduced seed, pH value and permeate yield were studied. For the implementation of the technology membrane apparatus with open channels are used that are resistant to the impact of membrane transfer of low-soluble salt deposits and suspended substances on the process. The developed by the authors technology of the concentrate utilization from reverse osmosis units installed at the heat power facilities for boiler feed water preparation is described. With the help of the developed technology softened water with lowered alkalinity and salt content can be produced. Herewith no chemicals are needed, and the unit does not consume water for its own needs. The technology provides for the complete utilization of reverse osmosis concentrate by improving its quality (in terms of hardness, alkalinity and total dissolved so­lids) to the requirements that allow using it for engineering purposes (for adding into a heat supply system or a circulation water supply system). Herewith any saline discharges into the environment are eliminated.

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